WO2010137014A2 - Photocatalytically assisted electrolysis and fuel cells - Google Patents

Photocatalytically assisted electrolysis and fuel cells Download PDF

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Publication number
WO2010137014A2
WO2010137014A2 PCT/IL2010/000413 IL2010000413W WO2010137014A2 WO 2010137014 A2 WO2010137014 A2 WO 2010137014A2 IL 2010000413 W IL2010000413 W IL 2010000413W WO 2010137014 A2 WO2010137014 A2 WO 2010137014A2
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Prior art keywords
electrodes
electrode
light
npe
nanoparticles
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PCT/IL2010/000413
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French (fr)
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WO2010137014A3 (en
Inventor
Shmuel Bukshpan
Gleb Zilberstein
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H4 Ltd.
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Publication of WO2010137014A3 publication Critical patent/WO2010137014A3/en

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M14/00Electrochemical current or voltage generators not provided for in groups H01M6/00 - H01M12/00; Manufacture thereof
    • H01M14/005Photoelectrochemical storage cells
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/86Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/8647Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
    • H01M4/8657Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites layered
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/86Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88Processes of manufacture
    • H01M4/8825Methods for deposition of the catalytic active composition
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/10Process efficiency
    • Y02P20/133Renewable energy sources, e.g. sunlight

Definitions

  • the present invention relates to the fields of electrolysis and fuel cells. More specifically, the present invention pertains to electrolysis and fuel cells assisted by localized surface plasmon resonance induced by illumination of photocatalytic electrodes coated with metal nanoparticles.
  • Electrolysis of water is the decomposition of water (H 2 O) into oxygen (O 2 ) and hydrogen gas (H 2 ) due to an electric voltage generating a current through the water.
  • An electrical power source is connected to two electrodes, or two plates (typically made from some inert metal such as platinum or stainless steel) which are placed in the water.
  • hydrogen will appear at the cathode (the negatively charged electrode), and oxygen will appear at the anode (the positively charged electrode).
  • the amount of hydrogen generated is twice the number of moles of oxygen, and both are proportional to the total electrical charge conducted by the solution.
  • Electrolysis of water requires excess energy in the form of over- potential in order to overcome various activation barriers. Without the excess energy the electrolysis of pure water occurs very slowly or not at all. This is in part due to the limited self-ionization of water. Pure water has an electrical conductivity about one millionth that of seawater. Many electrolytic cells may also lack the requisite electro- catalysts. The efficacy of electrolysis is increased through the addition of an electrolyte (such as a salt, an acid or a base) and the use of electro catalysts.
  • an electrolyte such as a salt, an acid or a base
  • half reactions can also be balanced with base as listed below. Not all half reactions must be balanced with acid or base. Many do require balancing, like the oxidation or reduction of water listed here. To add half reactions they must both be balanced with either acid or base.
  • the number of hydrogen molecules produced is thus twice the number of oxygen molecules. Assuming equal temperature and pressure for both gases, the produced hydrogen gas has therefore twice the volume of the produced oxygen gas.
  • US Patent 6471 834 discloses an apparatus using the photo collector/cathode which comprises a thin layer of metal, preferably nickel, deposited by electroplating or a similar technique onto a conductive surface. During the electrolysis process, the cathode is irradiated with light, thereby reducing the amount of electrical energy necessary to separate a given quantity of electrolytic material.
  • US Patent 7271334 discloses a photocatalytic film of semiconducting iron oxide (Fe 2 O 3 ), containing an n-dopant, or a mixture of n-dopants, or a p-dopant or a mixture of p- dopants.
  • the electrode consists of a substrate, with one or more films or photocatalytic arrangements of film of semiconducting n-doped or p-doped iron oxide e.g. on the surface of one side of the substrate or on the surface of different sides.
  • the photoelectrochemical cell comprises electrodes with a film or with films of the n-doped or p-doped semiconducting iron oxide.
  • the semiconducting iron oxide film can be manufactured with a spray pyrolysis process or a sol gel process.
  • the system for the direct cleavage of water with visible light, into hydrogen and oxygen comprises one or more of the photoelectrochemical cells with photocatalytic films.
  • the system can be a tandem cell system, comprising the photoelectrochemical cell with the doped iron oxide film.
  • US Patent 7295723 discloses plasmons on a waveguide delivering energy to initiate a photocatalytic reaction.
  • the waveguide or other energy carrier may be configured to carry electromagnetic energy and generate plasmon energy at one or more locations proximate to the waveguide, where the plasmon energy may react chemically with a medium or interaction material.
  • US Patent Application 2009/0032391 discloses a photolysis-assisted electrolysis device comprising at least one fluidized bed disposed in the device's housing.
  • the fluidized bed comprises a reaction medium and photolysis-catalyzing nanoparticles suspended in the reaction medium. When the fluidized bed is exposed to light, the nanoparticles catalyzes the photolysis of the reaction medium to form donor electrons.
  • the donor electrons promote reduction of the reaction medium during an electrolysis reaction, for example, the reduction of water to form hydrogen gas.
  • US Patent 6936143 discloses a tandem cell or photoelectrochemical system for the cleavage of water to hydrogen and oxygen by visible light having two superimposed photocells, both cells being connected electrically.
  • the photoactive material in the top cell is a semiconducting oxide placed in contact with an aqueous solution. This semiconducting oxide absorbs the blue and green part of the solar emission spectrum of a light source or light sources and generates with the energy collected, oxygen and protons from water.
  • the unabsorbed yellow and red light transmits through the top cell and enters a second photocell, the bottom cell, which is mounted, in the direction of the light behind, preferably directly behind the top cell.
  • the bottom cell includes a dye-sensitized mesoporous photovoltaic film. The bottom cell converts the yellow, red and near infrared portion of the solarlight to drive the reduction of the protons, which are produced in the top cell during the photo catalytic water oxidation process, to hydrogen.
  • US Patent Application 2005/0059186 discloses a method of making a photoelectrode.
  • the photoelectrode comprises a semiconductor layer having a first and second opposite major surfaces, with the first major surface overlaid with a layer of indium tin oxide having a thickness, crystal structure, and composition sufficient for robust operation in an electrochemical cell for electrolysis of water.
  • Japanese Patent Application P2005-076268 discloses a hydrogen generation device, which has visible light responding photocatalyst in contact with water or aqueous solution containing a sacrificial agent.
  • a visible light source is capable of emitting visible light within the range of 380 to 500 nm onto said photocatalyst, and can conduct water oxidation-reduction reaction to produce hydrogen gas.
  • the visible light responding photocatalyst is loaded with cocatalyst, such as Pt, NiO, RuO 2 and IrO 2 , etc.
  • the photocatalyst is also loaded with particles absorbing Au surface plasmon polaritons or particles absorbing Ag surface plasmon polaritons.
  • a hydrogen generation method that uses said hydrogen generation device to enable visible light responding photocatalyst to contact with water or aqueous solution containing sacrificial agent and employs a visible light source to irradiate said photocatalyst to produce hydrogen gas.
  • a hydrogen generation system which has a unit for supplying water or aqueous solution containing sacrificial agent to said hydrogen generation device, and a unit for controlling hydrogen generation amount.
  • the silver nanoparticles transfer the absorbed energy to the recited catalysts.
  • NPE metal nanoparticles
  • Another object of the invention is to provide the photocatalytic reactor characterized by having at least one NPE.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a photocatalytic reactor is characterized by having at least one light-illuminated NPE.
  • the illumination by the light is provided either directly or indirectly
  • a further object of this disclosure is to disclose the abovementioned invention wherein a photocatalytic reactor is characterized by having at least one solar light-illuminated NPE.
  • the illumination by the solar light is provided either directly or indirectly.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the light-illuminated NPE is useful for inducing plasmon surface resonance (PSR).
  • PSR plasmon surface resonance
  • a further object of this disclosure is to disclose the abovementioned invention wherein the solar light-illuminated NPE is useful for inducing plasmon surface resonance (PSR).
  • PSR plasmon surface resonance
  • a further object of this disclosure is to disclose the abovementioned invention wherein a light assisted fuel cell is characterized by having at least one light-illuminated NPE.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a light assisted fuel cell is characterized by having at least one solar light-illuminated NPE.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the light induced electrolysis cell is characterized by having at least one light-illuminated NPE.
  • the illumination is provided either directly or indirectly.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the light induced electrolysis cell is characterized by having at least one solar-illuminated NPE. The solar illumination is provided either directly or indirectly.
  • a further object of this disclosure is to disclose the abovementioned invention wherein NPE is characterized by more than 5% reduction in energy consumption (KWh electric/mole H 2 ) compared with non-solar illuminated or non-nanoparticles coated electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the fuel cell characterized by at least one of the following: (a) more than 2.5% increase of electrical efficiency compared with non-illuminated electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the fuel cell further comprises diaphragm, such as polysulfone or ceramic diaphragms.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrolysis cell characterized by at least one of the following: (a) more than 5% reduction in energy consumption (KWh electric/mole H 2 ) compared with a non-light illuminated or non-nanoparticles coated electrodes;
  • a further object of this disclosure is to disclose the abovementioned invention wherein the fuel cells are characterized by (a) an electrolyte; and (b) at least one electrode in connection with said electrolyte; wherein at least one of the following is held true: (a) said electrode is at least partially coated by metal nanoparticles (NPE); (b) said electrode is characterized by light induced effect; (c) Increment (%) vs Klux plot is 0.64 or more; or, (d) said electrode performance is characterized by more than 5% reduction in energy consumption (KWh electric/mole H 2 ) compared with a non-light illuminated or non- nanoparticles coated electrodes.
  • NPE metal nanoparticles
  • Increment (%) vs Klux plot is 0.64 or more
  • said electrode performance is characterized by more than 5% reduction in energy consumption (KWh electric/mole H 2 ) compared with a non-light illuminated or non- nanoparticles coated electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the fuel cells additionally comprises illuminating means adapted to provide at least one of the following: light collector, light delivering means, and electrode light illuminator.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the illuminating means comprises at least one element selected from a group consisting of light scatterers, lenses, optic fibres, mirrors, transparent electrode's separators, semitransparent electrodes, diffractive optical elements and any combination thereof
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is accommodated in a container; said electrodes are inserted into said electrolyte and electrically connectable to a load; a space between said electrodes is divided by means of a proton exchange membrane; said electrodes are illuminated by said illuminating means; wherein the electrolysis cells are characterized by (a) an electrolyte; and (b) at least two electrodes in connection with said solution; wherein at least one of the following is being held true (a) at least one of said electrodes is at least partially coated by nanoparticles (NPE); (b) at least one of said electrodes is characterized by light induced effect; (c) Increment (%) vs Klux plot is 0.65 or more; or, (d) said electrode reduces, by more than 5%, the electrolysis cell's energy consumption (KWh electric/mole H 2 ) compared with a non- illuminated or non-nanoparticles coated electrodes;
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrolysis cells additionally comprises illuminating means adapted to provide at least one of the following: light collector, light delivering means, and electrode light illuminator.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the illuminating means comprises at least one element selected from a group consisting of light scatterers, lenses, optic fibres, mirrors, transparent electrode's separators, transparent electrodes, diffractive optical elements , multifiber scattering elements and any combination thereof
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is accommodated in a container; said electrodes are inserted into said electrolyte and electrically connectable to a voltage source; a space between said electrodes is divided by means of a proton exchange membrane; said electrodes are illuminated by said illuminating means.
  • the said metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the nanoparticals comprising metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the, per specific metal, said metal nanoparticles are distributed over sizes corresponding to maximum operability according to the spectral distribution of the induced illumination.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
  • a further object of this disclosure is to disclose the abovementioned invention, wherein said size distribution is obtained by: spraying, spin coating, ink jet, chemical deposition all characterized by pre- prepared or predetermined size distribution.
  • the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution
  • a further object of this disclosure is to disclose the abovementioned invention, wherein the cells further comprises a proton exchange membrane, a ceramic diaphragm or other separating media like polysulphone and other membranes for separation of gases generated by the apparatus
  • a further object of this disclosure is to disclose the abovementioned invention wherein a fuel cell stack is characterized by having a plurality of n fuel cells, n is an integer equal or greater 2.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the illuminating means comprises an extraneous radiation collecting element.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said illuminating means further comprises a delivering means part adapted to deliver said solar radiation to said NPE surfaces.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said illuminating means comprises light sensing means.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said collecting system additionally comprises at least one optical element selected from the group consisting of lens, a curvilinear mirror, diffractive optical element and any combination thereof.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the collecting portion comprises an optical collimator.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said delivering portion comprises at least one selected from a taper, a light-guide , an optical fibre and a planar scattering optical element (insert) configured for placement thereof in a gap between electrodes and illumination thereof or any combination of the same.
  • the said delivering portion comprises at least one selected from a taper, a light-guide , an optical fibre and a planar scattering optical element (insert) configured for placement thereof in a gap between electrodes and illumination thereof or any combination of the same.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said delivering portion additionally comprising a scattering optical element.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said illuminating means is a transparent polymer.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the transparent polymer is selected from a group consisting of polycarbonates, poly(methyl metaacrylates) (PMMA, e.g., Lucite, or Perspex) and derivatives thereof.
  • PMMA poly(methyl metaacrylates)
  • NPE nanoparticles
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrodes are disposed at an acute angle; a scattering element is disposed so that said extraneous radiation being incident on said scattering element is scattered thereby onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a reflecting surface operable for directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a tapered conical surface reflecting operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a parabolic surface reflecting operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a diffractive optical element operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method for producing at least partially coated electrode.
  • the method comprises the steps of: (a) providing an electrode; (b) at least partially coating said electrode with by metal nanoparticles (NPE), having predetermined size distribution;
  • the size distribution of said metal nanoparticles is adapted for maximal light absorption and for optimal localized surface plasmon polarization (LSPR) with the visible optical spectrum used for illumination.
  • LSPR localized surface plasmon polarization
  • a further object of this disclosure is to disclose the abovementioned invention wherein the step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically attaching, adsorbing or otherwise adding metal nanoparticles to said electrode.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a light induced electrode.
  • the method comprises the steps of: (a) providing an electrode; (b) at least partially coating said electrode with by metal nanoparticles CNPE), having predetermined size distribution; thereby providing a light induced NPE.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a photocatalytic reactor, wherein said method comprising the steps of: (a) providing an electrode; (b) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; thereby providing a light induced NPE.
  • NPE nanoparticles
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method is useful for inducing plasmon surface resonance (PSR).
  • PSR plasmon surface resonance
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a fuel cell, comprises the steps of: (a) providing an electrolyte; (b) providing at least one electrode in connection with said electrolyte; (c) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; such that at least one of the following is held true: (1) said electrode is at least partially coated by nanoparticles (NPE); (2) said electrode is characterized by light induced effect; or, (3) * more than 2.5% increase of electrical efficiency compared with non-illuminated or non-nanoparticles coated electrodes.
  • NPE nanoparticles
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically etching, adsorbing or otherwise adding metal nanoparticles to said electrode.
  • the method additionally comprises a step of providing illuminating means for enabling at least one of the following: light collector, light delivering means, and electrode light illuminator.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a electrolysis cell comprises the steps of: (a) providing an electrolyte; (b) providing at least one electrode in connection with said solution; (c) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; such that at least one of the following is being held true: (1) said electrode is at least partially coated by nanoparticles (NPE); (2) said electrode is characterized by light induced effect; or,(3) said electrode reduces, by more than 5%, the electrolysis cell's energy consumption (KWh/mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes.
  • NPE nanoparticles
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method of photocatalysis in electrolysis cells comprises the steps of (a) providing a fuel cell further comprising (i) an electrolyte; and (ii) at least one electrode in connection with said solution; said electrode is at least partially coated by metal nanoparticles (NPE); (b) illuminating said electrodes with extraneous radiation.
  • NPE metal nanoparticles
  • the method further comprises a step of light inducing effect such that the Increment (%) vs Klux plot is 0.64 or more or said electrode performance is characterized by more than 5% reduction in energy consumption (KWh electric/mole H 2 ) compared with a non-solar illuminated or non-nanoparticles coated electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a step of illuminating is performed by illuminating means comprising at least one of the following: light collector, light delivering means, and electrode light illuminator.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is provided being accommodated in a container.
  • the electrodes are provided being inserted into said electrolyte and electrically connectable to a load; a proton exchange membrane is provided which divides a space between said electrodes; said electrodes are illuminated by said illuminating means.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method of photocatalysis in fuel cells comprises the steps of (a) providing a fuel cell further comprising (i) an electrolyte; and (ii) at least one electrode in connection with said solution; said electrode is at least partially coated by metal nanoparticles (NPE); (b) illuminating said electrodes with extraneous radiation.
  • NPE metal nanoparticles
  • the method further comprises a step of light inducing effect such that the Increment (%) vs Klux plot is 0.64 or more; or said electrode performance is characterized by more than 2.5% increase of electrical efficiency compared with non-illuminated or non-nanoparticles coated electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the step of illuminating is performed by illuminating means comprising at least one of the following: light collector, light delivering means, and electrode light illuminator.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is provided being accommodated in a container; said electrodes are provided being inserted into said electrolyte and electrically connectable to a load; a proton exchange membrane is providedwhich divides a space between said electrodes; said electrodes are illuminated by said illuminating means.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the provided metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the per specific metal, said provided metal nanoparticles are distributed over sizes corresponding to maximum operability according to the spectral distribution of the light source.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution.
  • NIPAM N-isopropyl acrylamide hydrogel
  • porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NTPAM and acrylic acid, porous Polystyrene- polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution.
  • NIPAM N-isopropyl acrylamide hydrogel
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method of manufacturing of a fuel cell stack comprising the steps of (a) providing a plurality of n fuel cells manufactured where either n is an integer equal or greater 2 and (b) integrating said cells into a monoblock unit.
  • a further object of this disclosure is to disclose the abovementioned invention wherein a method of manufacturing of a electrolysis cell stack comprising the steps of (a) providing a plurality of n electrolysis cells as aforementioned,such that n is an integer equal or greater 2 and (b) integrating said cells into a monoblock unit.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the step of illuminating said NPE comprises a step of collecting extraneous radiation.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the step of illuminating said NPE comprises a step of sensing and adjusting said illuminating means.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the said electrodes are disposed at an acute angle and illuminated by a scattering element disposed so that said extraneous radiation being incident on said scattering element is directed thereby onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation reflected by a reflecting surface operable for directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation reflected by a tapered conical surface operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation reflected by a parabolic surface operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation diffracted by a diffractive optical element operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
  • a further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation delivered by a planar diffracting element(insert) positioned adjacent to the electrode.
  • a further object of this disclosure is to disclose the abovementioned invention wherein NPE is characterized by metal nanoparticles a size distribution which is predefined to provide a maximum light induced effect in varied location, hight and time of the day.
  • Fig. 1 presentsjncrement (%) vs Klux in Electrolysis Cells (EC) & Fuel Cells (FC), according to Tables IA and IB;
  • Fig. 2 is a schematic diagram of the photocatalytic electrode assembly
  • Fig. 3 is a schematic diagram of the photocatalytic electrolytic cell
  • Fig. 4 is a schematic electric diagram of the photocatalytic electrode assembly apparatus
  • Figs 5 and 6 are microphotographs of the surfaces of the photocathalytic electrodes coated with nanoparticles of silver and platinized titanium, respectively;
  • Fig. 7 is a schematic arrangement of the scattering elongate elements placed between photocathalytic electrodes
  • Fig. 8 is a graph of the spectrum of plasmon resonance absorption of silver nanoparticles
  • Fig. 9 is a graph of the spectrum of solar radiation
  • Fig. 10 is a schematic optical arrangement of the light delivery system.
  • Figs 1 Ia to l ie, 12a-b and 13 are alternative light delivery system embodiments.
  • SPR surface plasmon resonance
  • LSPR localized surface plasmon resonance
  • This phenomenon is the basis of many standard tools for measuring adsorption of material onto planar metal (typically gold and silver) surfaces or onto the surface of metal nanoparticles.
  • SPR surface plasmon resonance
  • LSPR localized surface plasmon resonance
  • This phenomenon is the basis of many standard tools for measuring adsorption of material onto planar metal (typically gold and silver) surfaces or onto the surface of metal nanoparticles.
  • Surface plasmons also known as surface plasmon polaritons, are surface electromagnetic waves that propagate in a direction parallel to the metal/dielectric (or metal/vacuum) interface. Since the wave is on the boundary of the metal and the external medium (air or water for example), these oscillations are very sensitive to any change of this boundary, such as the adsorption of molecules to the metal surface.
  • illumination means hereinafter refers to an illuminating optical arrangement (lighter) having a portion collecting extraneous radiation and a portion delivering said solar radiation to said electrode surfaces.
  • the collecting portion can include focusing elements such as lenses, mirrors and other optical elements.
  • An optical collimator used for concentration of extraneous radiation is in the scope of the current invention.
  • the term "light induced effect” hereinafter refers to the activation of a variety of phenomenon taking place on the electrode.
  • the utilizable phenomena is excitation of surface plasmon resonance.
  • SPR surface plasmon resonance
  • LSPR localized surface plasmon resonance
  • surface plasmons e.g., surface plasmon polaritons
  • 'SPR' and 'LSPR' will interchangeably used in this patent.
  • LSPR localized surface plasmon polaritons
  • FC fuel cell'
  • the term 'fuel cell' (FC) refers hereinafter to an electrochemical cell that converts a source fuel into an electrical current.
  • the FC generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte.
  • the reactants flow into the cell, and the reaction products flow out of it, while the electrolyte remains within it.
  • Fuel cells can operate virtually continuously as long as the necessary flows are maintained. Many combinations of fuels and oxidants are possible.
  • a hydrogen fuel cell uses hydrogen as its fuel and oxygen (usually from air) as its oxidant.
  • Other fuels include hydrocarbons and alcohols.
  • Other oxidants include chlorine and chlorine dioxide.
  • the fuel cells of the present invention are typically, yet not exclusively, made up of three segments which are sandwiched together: the anode, the electrolyte, and the cathode. It is in the scope of the invention wherein two chemical reactions occur at the interfaces of the three different segments. The net result of the two reactions is that fuel is consumed, water or carbon dioxide is created, and an electrical current is created, which can be used to power electrical devices, normally referred to as the load. It is also in the scope of the invention wherein at the anode a catalyst oxidizes the fuel, usually hydrogen, fuel into is turning a positively charged ion and a negatively charged electron.
  • the electrolyte is a substance specifically designed so ions can pass through it, but the electrons cannot.
  • a proton- conducting polymer membrane (the electrolyte), separates the anode and cathode sides.
  • hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons.
  • protons may react with oxidants causing them to become what is commonly referred to as multi-facilitated proton membranes.
  • the protons are conducted through the membrane to the cathode, but the electrons are forced to travel in an external circuit (supplying power) because the membrane is electrically insulating.
  • the cathode catalyst oxygen molecules react with the electrons (which have traveled through the external circuit) and protons to form water - in this embodiment, the only waste product, either liquid or vapor.
  • hydrocarbon fuels for fuel cells including diesel, methanol and chemical hydrides.
  • the waste products with these types of fuel are carbon dioxide and water.
  • the materials used in fuel cells differ by type.
  • the electrode-bipolar plates are usually made of metal, nickel or carbon nanotubes, and are coated with a catalyst (like platinum, nano iron powders or palladium) for higher efficiency. Carbon paper separates them from the electrolyte.
  • the electrolyte could be ceramic or a membrane.
  • the fuel cell further comprises diaphragm, such as polysulfone or ceramic diaphragms.
  • SOFC Solid oxide fuel cell
  • SOFCs can use nickel or other catalysts to break apart the methanol and create hydrogen ions and CO 2 .
  • a solid yttrium stabilized zirconium (YSZ) is used as the electrolyte.
  • the standard operating temperature is about 95O 0 C http://en.wikipedia.org/wiki/Fuel cell - cite note-sahibzada-12#cite note-sahibzada-12.
  • the term 'electrolysis cell' and 'electrolytic cell' (EC) interchangeably refers hereinafter to a cell decomposes chemical compounds by means of electrical energy, in an electrolysis process. The result is that the chemical energy is increased. It is in the scope of the invention wherein the electrolytic cell comprises three component parts: an electrolyte and two electrodes (a cathode and an anode).
  • the electrolyte is usually a solution of water or other solvents in which ions are dissolved. Molten salts such as sodium chloride are also electrolytes.
  • the electrolyte When driven by an external voltage applied to the electrodes, the electrolyte provides ions that flow to and from the electrodes, where charge-transferring, or faradaic, or redox, reactions can take place. Only for an external electrical potential (i.e., voltage) of the correct polarity and large enough magnitude can an electrolytic cell decompose a normally stable or inert chemical compound in the solution. The electrical energy provided undoes the effect of spontaneous chemical reactions. It is also in the scope of the invention wherein the cathode is the electrode to which cations flow (positively charged ions, like silver ions Ag+), to be reduced by reacting with (negatively-charged) electrons on the cathode.
  • the cathode is the electrode to which cations flow (positively charged ions, like silver ions Ag+), to be reduced by reacting with (negatively-charged) electrons on the cathode.
  • anode is the electrode to which anions flow (negatively charged ions, like chloride ions Cl-), to be oxidized by depositing electrons on the anode.
  • anions flow negatively charged ions, like chloride ions Cl-
  • the cathode is positive and the anode is negative.
  • the term "collimator” hereinafter refers to a device adapted to change a cross section of a light beam.
  • the collimator comprises at least two confocally placed focusing elements (lenses, mirrors, diffraction optical elements.
  • 'coated' or 'coating' is interchangeably refer hereinafter to a step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically attaching, adsorbing or otherwise adding metal nanoparticles to said electrode.
  • Fig. 2 presenting Increment (%) vs Klux in Electrolysis Cells (EC) & Fuel Cells (FC), according to Tables IA and IB.
  • the term 'article of manufacture refers to one or more of the following: means which provides power for base stations or cell sites; Off-grid power supply; Distributed generation; Fork Lifts; Emergency power systems are a type of fuel cell system, which may include lighting, generators and other apparatus, to provide backup resources in a crisis or when regular systems fail.
  • An uninterrupted power supply provides emergency power and, depending on the topology, provide line regulation as well to connected equipment by supplying power from a separate source when utility power is not available; Unlike a standby generator, it can provide instant protection from a momentary power interruption; Base load power plants; Electric and hybrid vehicles.; Notebook computers for applications where AC charging may not be available for weeks at a time; Portable charging docks for small electronics (e.g.
  • Smartphones with high power consumption due to large displays and additional features like GPS might be equipped with micro fuel cells; Small heating appliances; vehicle, satellite, air craft, marine and vessel, means of transportation, means of generating electricity and power source, engine, fork lifts, hydrogen fuelling stations, buildings, domestic buildings, hydrogen storage for alternative energy utilizations such as solar, wind, nuclear, hydro etc.
  • anodes 121 and cathodes 124 are separated by a separator 122 and a proton exchange membrane 123.
  • the aforesaid EC/FC 100 comprises a container 20 comparted into two compartments by a proton exchange membrane 30.
  • the photocatalytic electrodes 50 are inserted into the container 20 filled an electrolyte.
  • the electrodes 50 are barred or seperated from each other by means of separators 40.
  • a light concentrator 10 is adapted to concentrate the extraneous radiation 140.
  • the concentrated radiation is delivered to the electrodes 50 by means of optical fibers 70 and scattering elements 80.
  • the photocathalytic electrodes 50 are electrically connected to a voltage source 60.
  • the photocathalytic electrodes 50 are coated with metal nanoparticles operable for localized surface plasmon resonance induced by said illumination being incident onto electrolysis electrode surfaces coated with metal nanoparticles.
  • the photocatalytic cell includes a pair of electrodes 50 (3 cm x 100 cm).
  • the aforesaid photocatalyic cells can be grouped into an array.
  • proton exchange membrane or “polymer electrolyte membrane” (PEM) refers to a semi-permeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen. This is their essential function when incorporated into a membrane electrode assembly (MEA) of a proton exchange membrane fuel cell or of a proton exchange membrane electrolyser : separation of reactants and transport of protons.
  • MEA membrane electrode assembly
  • PEMs can be made from either pure polymer membranes or from composite membranes where other materials are embedded in a polymer matrix.
  • One of the most common and commercially available PEM materials is National, a DuPont product.
  • the membrane is a proton exchange membrane, a ceramic diaphragm or other separating media like polysulphone and other membranes for separation of gases generated by the apparatus
  • LSP are collective electronic excitations near the surface of metallic particles nanoparticles.
  • a resonance wavelength increases with a size of nanoparticles.
  • optical excitation of plasmon resonances in metallic nanoparticles results in an enhanced local electromagnetic field around the particles.
  • the field distribution depends on the particle parameters such as size, shape, optical constants and surrounding dielectric medium.
  • the disclosed approach is applied to water electrolysis. This is advantageous in that when the nanoparticle coated electrodes are illuminated by the radiation of the wavelength corresponding to LSP resonance, the same hydrogen amount will be dissociated at less energy consumption in comparison with non illuminated electrodes known in the art . In corollary the electrodes of the present invention provide a greater amount of hydrogen at the same energy consumption, compared to the prior art non illuminated electrodes.
  • FIG. 4 presenting a photocatalytic electrode assembly 115 comprising cathodes and anodes 120 and 125 connected to the voltage source 60 in parallel.
  • Figs 5 and 6 presenting electron microscope images of electrodes coated with silver nanoparticles and platinised titanium, respectively.
  • the silver nanoparticles have sizes ranging between 50 and 300 nm.
  • the metal nanoparticles are immobilized on a surface of electrode by means of a porous gel template.
  • the porous gel template is made of a gel based on agarose, polyacrylamide or other like compounds.
  • Elongate optical elements 130 are inserted into a space between the photocathalytic electrodes 120.
  • the optical elements 130 constitute rods of square or rectangular cross-section. Side surfaces of the rods are sanded such that they scatter the light provided to them. Thus, the optical elements 130 provide sufficiently uniform illumination of surfaces of the photocathalytic electrodes 120.
  • Figs 8 and 9 presenting spectrum of plasmon resonance absorption of silver nanoparticles and solar radiation spectrum.
  • illumination of the photocathalytic electrodes can be performed by collected solar radiation.
  • the aforesaid lighter 200 comprises two collimator lenses 150 and 160, fiber-optic taper 170, light-guide fiber 180 and elongate optical element 130.
  • a parallel beam of solar radiation 140 is narrowed down by the lens 150 and 160. Then, the narrowed beam is inserted into the light-guide fiber 180 by means of the taper 170.
  • the fiber 180 delivers the solar radiation to the elongate optical element 130 which is placed in the space between the photocathalytic electrodes 120 (not shown). Radiation 135 scattered on side surface of the optical element 130 is operable to excite plasmon resonance.
  • the most advantage of the current invention is that when the nanoparticle coated electrodes are illuminated by the radiation of the wavelength corresponding to LSP resonance, the same hydrogen amount will be dissociated at less energy consumption in comparison with electrodes known in the art without illumination or greater amount of hydrogen will be provided at the same energy consumption. Comparing Fig. 5 with Fig. 6, we can see that the solar radiation spectrum is very satisfactory for excitation of LSP resonance.
  • Electrodes 120 are disposed at an acute angle.
  • a scattering element 131 is disposed so that said extraneous radiation 140 being incident on the scattering element 131 is scattered thereby onto the electrodes 120.
  • a reflecting surface 132 is operable for directing said radiation onto said electrodes.
  • a tapered reflecting conical surface 133 is operable for concentrating extraneous radiation 140 and directing said radiation onto said electrodes 120.
  • a parabolic reflecting surfacel33 is operable for concentrating extraneous radiation 140 and directing said radiation onto the electrodes 120.
  • a diffractive optical element 134 is operable for concentrating extraneous radiation 140 and directing the radiation onto the electrodes 120.
  • Fig. 12a presenting an alternative embodiment of light delivering arrangement comprising a bundle of optical fibres 180 carrying the extraneous radiation to the electrodes 120 and 125.
  • Optical fibres 136 are inserted between the electrodes 120 and 125 and operable for scattering the aforesaid radiation in direction of the electrodes 120 and 125.
  • Fig. 12b is the same, wherein optical fibres 136 are set adjacent the electrode as a net or crossed array of fibres.
  • Fig. 13 presenting an alternative embodiment of spacer 40.
  • the extraneous radiation 140 enters into the spacer 40.
  • the radiation 135 scattered at side surfaces of the spacer 40 illuminates the neighbouring electrode 120.
  • a water electrolysis cell was assembled using two coated Ag electrodes (50x50mm) with a distance between electrodes of 50mm. Electrolysis of 0.1% water solution of KOH (50ml) was initiated by applying an external voltage under extraneous illumination. A Halogen -light source (30W) was employed for the illumination of the nanoparticle coated electrode.
  • Raw material is colloidal Au (SIGMA 636347). Particles of size lOOnm were deposited on a gold electrode by welding in argon atmosphere on the Au surface. Electrolysis experiments were performed in a cell consisting of two Au electrodes (50x5 Omm). The distance between electrodes was 50mm. The electrolyte was 0.1% water solution of KOH (50ml). The electrolysis initiation under illumination (3OW halogen lamp) was at the voltage of 0.8 V. EXAMPLE 3
  • FIG 1 An electrode assembly as shown in Fig 1 was photocathalytically coated with silver nano particles as described in Example 1. The particle distribution over sizes is presented in Fig 2.
  • Amounts of gas generated on the electrode assembly were measured at a number of values of the voltage applied to the electrode assembly. The amounts of the gas generated on illuminated and non-illuminated assembly are compared, as well. 15 % solution of potassium sulphate (K 2 SO 4 ) in double distilled water was used as an electrolyte. The optical arrangement shown in Fig. 7 was used for illuminating the photocathalytic electrodes. In the current example a number of halogen lamps were used as a light source instead of solar radiation. The lack of UV radiation in the emission spectrum of halogen lamps in comparison with the solar radiation should be noted.
  • the illuminance was measured at the output surface of the light guide by using a commercial photometer.
  • the illuminances used in this experiment were 60kLux and 105 kLux approximately simulating the intensity of non concentrated solar light and twice concentrated solar light intensity.
  • FIG. 1 presentsjncrement (%) vs Klux in Electrolysis Cells (EC) & Fuel Cells (FC), according to Tables IA and IB above.
  • Titanium electrodes electroplated with 2 micron thick platinum (purchased from Ti Anode Fabricators Pvt. Ltd., India) exhibited nano structured features as shown in Fig.3.
  • the electrodes lOmmxlOOmm were mounted in the photocathalytic cell.
  • An electrode-containing cell (either FC or EC), at least partially coated by metal nanoparticles (NPE), characterized by a light induced effect, comprising at least one fluidized bed located nearby at least one electrode; fluidized bed comprises said photocatalytic nanoparticles.
  • NPE metal nanoparticles
  • Optimal size distribution of the nanoparticles is obtained by various techniques, namely: gel template; chemical deposition and reduction, and spray pyrolysis.
  • the electrical efficiency of fuel cell is found to be more than 2.5% increase of electrical efficiency compared with (standard-) non-illuminated electrodes.

Abstract

An apparatus and methods for improvement of photoelectrolysis and fuel cells are disclosed. The aforesaid apparatus comprises (a) a container filled by a compound to be electrolyzed; (b) photocatalytic electrodes positioned in the container; the electrodes are connectable to a source of voltage; and (c) illuminating means adapted to provide illumination to the electrodes. The electrodes are coated with metal nanoparticles operable for localized surface plasmon resonance induced by the illumination being incident onto electrolysis electrode surfaces coated with metal nanoparticles.

Description

PHOTOCATALYTICALLY ASSISTED ELECTROLYSIS AND FUEL CELLS
REFERENCE TO RELATED PUBLICATION
[01] This application claims priority from U.S. provisional application 61/180,897, dated 25 May 2009, which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to the fields of electrolysis and fuel cells. More specifically, the present invention pertains to electrolysis and fuel cells assisted by localized surface plasmon resonance induced by illumination of photocatalytic electrodes coated with metal nanoparticles.
BACKGROUND OF THE INVENTION
Electrolysis of water is the decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) due to an electric voltage generating a current through the water.
An electrical power source is connected to two electrodes, or two plates (typically made from some inert metal such as platinum or stainless steel) which are placed in the water. In a properly designed cell, hydrogen will appear at the cathode (the negatively charged electrode), and oxygen will appear at the anode (the positively charged electrode). Assuming ideal Faradaic efficiency, the amount of hydrogen generated is twice the number of moles of oxygen, and both are proportional to the total electrical charge conducted by the solution.
Electrolysis of water requires excess energy in the form of over- potential in order to overcome various activation barriers. Without the excess energy the electrolysis of pure water occurs very slowly or not at all. This is in part due to the limited self-ionization of water. Pure water has an electrical conductivity about one millionth that of seawater. Many electrolytic cells may also lack the requisite electro- catalysts. The efficacy of electrolysis is increased through the addition of an electrolyte (such as a salt, an acid or a base) and the use of electro catalysts.
In the water at the negatively charged cathode, a reduction reaction takes place, with electrons (e~) from the cathode being given to hydrogen cations to form hydrogen gas (the half reaction balanced with acid):
Cathode (reduction): 2 H+(^) + 2e~ → H2(g)
At the positively charged anode, an oxidation reaction occurs, generating oxygen gas and giving electrons to the anode to complete the circuit:
Anode (oxidation): 2 H2O(Z) → O2(g) + 4 H+(^) + 4e~
The same half reactions can also be balanced with base as listed below. Not all half reactions must be balanced with acid or base. Many do require balancing, like the oxidation or reduction of water listed here. To add half reactions they must both be balanced with either acid or base.
Cathode (reduction): 2 H2O(Z) + 2e~ → H2(g) + 2 0H(aq) Anode (oxidation): 4 OH'(aq) → O2(g) + 2 H2O(Z) + 4 e~
Combining either half reaction pair yields the same overall decomposition of water into oxygen and hydrogen:
Overall reaction: 2 H2O(Z) → 2 H2(g) + 02(g)
The number of hydrogen molecules produced is thus twice the number of oxygen molecules. Assuming equal temperature and pressure for both gases, the produced hydrogen gas has therefore twice the volume of the produced oxygen gas.
Decomposition of pure water into hydrogen and oxygen at standard temperature and pressure is not favorable in thermo dynamic terms.
Anode (oxidation): 2 H2O(Z) → O2(g) + 4 ϊ?{aq) + 4e~ Eoox = -1.23 V Cathode (reduction): 2 U+(aq) + 2e~ → H2(g) Eored = 0.00 V Thus, the standard potential of the water electrolysis cell is -1.23 V at 25 0C at pH 0 (H+ = 1.0 M). It is also -1.23 V at 25 °C at pH 7 (H+ = 1.0 x 10"7 M) based on the Nernst Equation.
The negative voltage indicates the Gibbs free energy for electrolysis of water is greater than zero for these reactions. This can be found using the G = -nFE equation from chemical kinetics, where n is the moles of electrons and F is the Faraday constant. The reaction cannot occur without adding necessary energy, usually supplied by an external electrical power source.
US Patent 6471 834 discloses an apparatus using the photo collector/cathode which comprises a thin layer of metal, preferably nickel, deposited by electroplating or a similar technique onto a conductive surface. During the electrolysis process, the cathode is irradiated with light, thereby reducing the amount of electrical energy necessary to separate a given quantity of electrolytic material.
US Patent 7271334 discloses a photocatalytic film of semiconducting iron oxide (Fe2O3), containing an n-dopant, or a mixture of n-dopants, or a p-dopant or a mixture of p- dopants. The electrode consists of a substrate, with one or more films or photocatalytic arrangements of film of semiconducting n-doped or p-doped iron oxide e.g. on the surface of one side of the substrate or on the surface of different sides. The photoelectrochemical cell comprises electrodes with a film or with films of the n-doped or p-doped semiconducting iron oxide. The semiconducting iron oxide film can be manufactured with a spray pyrolysis process or a sol gel process. The system for the direct cleavage of water with visible light, into hydrogen and oxygen comprises one or more of the photoelectrochemical cells with photocatalytic films. The system can be a tandem cell system, comprising the photoelectrochemical cell with the doped iron oxide film.
US Patent 7295723 discloses plasmons on a waveguide delivering energy to initiate a photocatalytic reaction. The waveguide or other energy carrier may be configured to carry electromagnetic energy and generate plasmon energy at one or more locations proximate to the waveguide, where the plasmon energy may react chemically with a medium or interaction material. US Patent Application 2009/0032391 discloses a photolysis-assisted electrolysis device comprising at least one fluidized bed disposed in the device's housing. The fluidized bed comprises a reaction medium and photolysis-catalyzing nanoparticles suspended in the reaction medium. When the fluidized bed is exposed to light, the nanoparticles catalyzes the photolysis of the reaction medium to form donor electrons. The donor electrons promote reduction of the reaction medium during an electrolysis reaction, for example, the reduction of water to form hydrogen gas.
US Patent 6936143 discloses a tandem cell or photoelectrochemical system for the cleavage of water to hydrogen and oxygen by visible light having two superimposed photocells, both cells being connected electrically. The photoactive material in the top cell is a semiconducting oxide placed in contact with an aqueous solution. This semiconducting oxide absorbs the blue and green part of the solar emission spectrum of a light source or light sources and generates with the energy collected, oxygen and protons from water. The unabsorbed yellow and red light transmits through the top cell and enters a second photocell, the bottom cell, which is mounted, in the direction of the light behind, preferably directly behind the top cell. The bottom cell includes a dye-sensitized mesoporous photovoltaic film. The bottom cell converts the yellow, red and near infrared portion of the solarlight to drive the reduction of the protons, which are produced in the top cell during the photo catalytic water oxidation process, to hydrogen.
US Patent Application 2005/0059186 discloses a method of making a photoelectrode. The photoelectrode comprises a semiconductor layer having a first and second opposite major surfaces, with the first major surface overlaid with a layer of indium tin oxide having a thickness, crystal structure, and composition sufficient for robust operation in an electrochemical cell for electrolysis of water.
Ewa Kowalska et al (Chem. Commun., 2 2009, 241-243) has performed action spectrum analyses which shows that visible light-induced oxidation of 2-propanol by aerated gold- modified titanium (IV) oxide (titania) suspensions is initiated by excitation of gold surface plasmon, and polychromatic irradiation experiments revealed that the photocatalytic reaction rate depends strongly on properties of titania, such as particle size, surface area and crystalline form (anatase or rutile) and on properties of gold deposits, such as size and shape.
Japanese Patent Application P2005-076268 ('268) discloses a hydrogen generation device, which has visible light responding photocatalyst in contact with water or aqueous solution containing a sacrificial agent. A visible light source is capable of emitting visible light within the range of 380 to 500 nm onto said photocatalyst, and can conduct water oxidation-reduction reaction to produce hydrogen gas. The visible light responding photocatalyst is loaded with cocatalyst, such as Pt, NiO, RuO2 and IrO2, etc. The photocatalyst is also loaded with particles absorbing Au surface plasmon polaritons or particles absorbing Ag surface plasmon polaritons. A hydrogen generation method that uses said hydrogen generation device to enable visible light responding photocatalyst to contact with water or aqueous solution containing sacrificial agent and employs a visible light source to irradiate said photocatalyst to produce hydrogen gas. A hydrogen generation system, which has a unit for supplying water or aqueous solution containing sacrificial agent to said hydrogen generation device, and a unit for controlling hydrogen generation amount.
In accordance with the '268, the silver nanoparticles transfer the absorbed energy to the recited catalysts. There is a long-felt and unmet need to use an electric field created by plasmons in the vicinity of the nanoparticle surface for increase in efficiency of electrolysis process.
SUMMARY OF THE INVENTION
It is hence one object of the invention to disclose an electrode, at least partially coated by metal nanoparticles (NPE), characterized by a light induced effect.
Another object of the invention is to provide the photocatalytic reactor characterized by having at least one NPE.
A further object of this disclosure is to disclose the abovementioned invention wherein a photocatalytic reactor is characterized by having at least one light-illuminated NPE. The illumination by the light is provided either directly or indirectly
A further object of this disclosure is to disclose the abovementioned invention wherein a photocatalytic reactor is characterized by having at least one solar light-illuminated NPE. The illumination by the solar light is provided either directly or indirectly.
A further object of this disclosure is to disclose the abovementioned invention wherein the light-illuminated NPE is useful for inducing plasmon surface resonance (PSR).
A further object of this disclosure is to disclose the abovementioned invention wherein the solar light-illuminated NPE is useful for inducing plasmon surface resonance (PSR).
A further object of this disclosure is to disclose the abovementioned invention wherein a light assisted fuel cell is characterized by having at least one light-illuminated NPE.
A further object of this disclosure is to disclose the abovementioned invention wherein a light assisted fuel cell is characterized by having at least one solar light-illuminated NPE.
A further object of this disclosure is to disclose the abovementioned invention wherein the light induced electrolysis cell is characterized by having at least one light-illuminated NPE. The illumination is provided either directly or indirectly. A further object of this disclosure is to disclose the abovementioned invention wherein the light induced electrolysis cell is characterized by having at least one solar-illuminated NPE. The solar illumination is provided either directly or indirectly.
A further object of this disclosure is to disclose the abovementioned invention wherein NPE is characterized by more than 5% reduction in energy consumption (KWh electric/mole H2) compared with non-solar illuminated or non-nanoparticles coated electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the fuel cell characterized by at least one of the following: (a) more than 2.5% increase of electrical efficiency compared with non-illuminated electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the fuel cell further comprises diaphragm, such as polysulfone or ceramic diaphragms.
A further object of this disclosure is to disclose the abovementioned invention wherein the electrolysis cell characterized by at least one of the following: (a) more than 5% reduction in energy consumption (KWh electric/mole H2) compared with a non-light illuminated or non-nanoparticles coated electrodes;
A further object of this disclosure is to disclose the abovementioned invention wherein the fuel cells are characterized by (a) an electrolyte; and (b) at least one electrode in connection with said electrolyte; wherein at least one of the following is held true: (a) said electrode is at least partially coated by metal nanoparticles (NPE); (b) said electrode is characterized by light induced effect; (c) Increment (%) vs Klux plot is 0.64 or more; or, (d) said electrode performance is characterized by more than 5% reduction in energy consumption (KWh electric/mole H2) compared with a non-light illuminated or non- nanoparticles coated electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the fuel cells additionally comprises illuminating means adapted to provide at least one of the following: light collector, light delivering means, and electrode light illuminator.
A further object of this disclosure is to disclose the abovementioned invention wherein the illuminating means comprises at least one element selected from a group consisting of light scatterers, lenses, optic fibres, mirrors, transparent electrode's separators, semitransparent electrodes, diffractive optical elements and any combination thereof
A further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is accommodated in a container; said electrodes are inserted into said electrolyte and electrically connectable to a load; a space between said electrodes is divided by means of a proton exchange membrane; said electrodes are illuminated by said illuminating means; wherein the electrolysis cells are characterized by (a) an electrolyte; and (b) at least two electrodes in connection with said solution; wherein at least one of the following is being held true (a) at least one of said electrodes is at least partially coated by nanoparticles (NPE); (b) at least one of said electrodes is characterized by light induced effect; (c) Increment (%) vs Klux plot is 0.65 or more; or, (d) said electrode reduces, by more than 5%, the electrolysis cell's energy consumption (KWh electric/mole H2) compared with a non- illuminated or non-nanoparticles coated electrodes;
A further object of this disclosure is to disclose the abovementioned invention wherein the electrolysis cells additionally comprises illuminating means adapted to provide at least one of the following: light collector, light delivering means, and electrode light illuminator.
A further object of this disclosure is to disclose the abovementioned invention wherein the illuminating means comprises at least one element selected from a group consisting of light scatterers, lenses, optic fibres, mirrors, transparent electrode's separators, transparent electrodes, diffractive optical elements , multifiber scattering elements and any combination thereof
A further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is accommodated in a container; said electrodes are inserted into said electrolyte and electrically connectable to a voltage source; a space between said electrodes is divided by means of a proton exchange membrane; said electrodes are illuminated by said illuminating means. A further object of this disclosure is to disclose the abovementioned invention wherein the said metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
A further object of this disclosure is to disclose the abovementioned invention wherein the nanoparticals comprising metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
A further object of this disclosure is to disclose the abovementioned invention wherein the, per specific metal, said metal nanoparticles are distributed over sizes corresponding to maximum operability according to the spectral distribution of the induced illumination.
A further object of this disclosure is to disclose the abovementioned invention wherein the said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
A further object of this disclosure is to disclose the abovementioned invention, wherein said size distribution is obtained by: spraying, spin coating, ink jet, chemical deposition all characterized by pre- prepared or predetermined size distribution.A further object of this disclosure is to disclose the abovementioned invention, wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution
A further object of this disclosure is to disclose the abovementioned invention, wherein the cells further comprises a proton exchange membrane, a ceramic diaphragm or other separating media like polysulphone and other membranes for separation of gases generated by the apparatus A further object of this disclosure is to disclose the abovementioned invention wherein a fuel cell stack is characterized by having a plurality of n fuel cells, n is an integer equal or greater 2.
A further object of this disclosure is to disclose the abovementioned invention wherein the illuminating means comprises an extraneous radiation collecting element.
A further object of this disclosure is to disclose the abovementioned invention wherein the said illuminating means further comprises a delivering means part adapted to deliver said solar radiation to said NPE surfaces.
A further object of this disclosure is to disclose the abovementioned invention wherein the said illuminating means comprises light sensing means.
A further object of this disclosure is to disclose the abovementioned invention wherein the said collecting system additionally comprises at least one optical element selected from the group consisting of lens, a curvilinear mirror, diffractive optical element and any combination thereof.
A further object of this disclosure is to disclose the abovementioned invention wherein the collecting portion comprises an optical collimator.
A further object of this disclosure is to disclose the abovementioned invention wherein the said delivering portion comprises at least one selected from a taper, a light-guide , an optical fibre and a planar scattering optical element (insert) configured for placement thereof in a gap between electrodes and illumination thereof or any combination of the same.
A further object of this disclosure is to disclose the abovementioned invention wherein the said delivering portion additionally comprising a scattering optical element.
A further object of this disclosure is to disclose the abovementioned invention wherein the said illuminating means is a transparent polymer.
A further object of this disclosure is to disclose the abovementioned invention wherein the transparent polymer is selected from a group consisting of polycarbonates, poly(methyl metaacrylates) (PMMA, e.g., Lucite, or Perspex) and derivatives thereof. A further object of this disclosure is to disclose the abovementioned invention wherein an article of manufacture comprising at least one electrode characterized by being at least partially coated by nanoparticles (NPE).
A further object of this disclosure is to disclose the abovementioned invention wherein the electrodes are disposed at an acute angle; a scattering element is disposed so that said extraneous radiation being incident on said scattering element is scattered thereby onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a reflecting surface operable for directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a tapered conical surface reflecting operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a parabolic surface reflecting operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the cells comprises a diffractive optical element operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein a method for producing at least partially coated electrode. The method comprises the steps of: (a) providing an electrode; (b) at least partially coating said electrode with by metal nanoparticles (NPE), having predetermined size distribution;
The size distribution of said metal nanoparticles is adapted for maximal light absorption and for optimal localized surface plasmon polarization (LSPR) with the visible optical spectrum used for illumination.
A further object of this disclosure is to disclose the abovementioned invention wherein the step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically attaching, adsorbing or otherwise adding metal nanoparticles to said electrode.
A further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a light induced electrode. The method comprises the steps of: (a) providing an electrode; (b) at least partially coating said electrode with by metal nanoparticles CNPE), having predetermined size distribution; thereby providing a light induced NPE.
A further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a photocatalytic reactor, wherein said method comprising the steps of: (a) providing an electrode; (b) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; thereby providing a light induced NPE.
A further object of this disclosure is to disclose the abovementioned invention wherein the method is useful for inducing plasmon surface resonance (PSR).
A further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a fuel cell, comprises the steps of: (a) providing an electrolyte; (b) providing at least one electrode in connection with said electrolyte; (c) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; such that at least one of the following is held true: (1) said electrode is at least partially coated by nanoparticles (NPE); (2) said electrode is characterized by light induced effect; or, (3) * more than 2.5% increase of electrical efficiency compared with non-illuminated or non-nanoparticles coated electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the said step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically etching, adsorbing or otherwise adding metal nanoparticles to said electrode. A further object of this disclosure is to disclose the abovementioned invention wherein the method additionally comprises a step of providing illuminating means for enabling at least one of the following: light collector, light delivering means, and electrode light illuminator.
A further object of this disclosure is to disclose the abovementioned invention wherein a method for producing a electrolysis cell comprises the steps of: (a) providing an electrolyte; (b) providing at least one electrode in connection with said solution; (c) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; such that at least one of the following is being held true: (1) said electrode is at least partially coated by nanoparticles (NPE); (2) said electrode is characterized by light induced effect; or,(3) said electrode reduces, by more than 5%, the electrolysis cell's energy consumption (KWh/mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the method of photocatalysis in electrolysis cells comprises the steps of (a) providing a fuel cell further comprising (i) an electrolyte; and (ii) at least one electrode in connection with said solution; said electrode is at least partially coated by metal nanoparticles (NPE); (b) illuminating said electrodes with extraneous radiation.
The method further comprises a step of light inducing effect such that the Increment (%) vs Klux plot is 0.64 or more or said electrode performance is characterized by more than 5% reduction in energy consumption (KWh electric/mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes..
A further object of this disclosure is to disclose the abovementioned invention wherein a step of illuminating is performed by illuminating means comprising at least one of the following: light collector, light delivering means, and electrode light illuminator.
A further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is provided being accommodated in a container. The electrodes are provided being inserted into said electrolyte and electrically connectable to a load; a proton exchange membrane is provided which divides a space between said electrodes; said electrodes are illuminated by said illuminating means. A further object of this disclosure is to disclose the abovementioned invention wherein a method of photocatalysis in fuel cells comprises the steps of (a) providing a fuel cell further comprising (i) an electrolyte; and (ii) at least one electrode in connection with said solution; said electrode is at least partially coated by metal nanoparticles (NPE); (b) illuminating said electrodes with extraneous radiation. The method further comprises a step of light inducing effect such that the Increment (%) vs Klux plot is 0.64 or more; or said electrode performance is characterized by more than 2.5% increase of electrical efficiency compared with non-illuminated or non-nanoparticles coated electrodes.
****
A further object of this disclosure is to disclose the abovementioned invention wherein the step of illuminating is performed by illuminating means comprising at least one of the following: light collector, light delivering means, and electrode light illuminator.
A further object of this disclosure is to disclose the abovementioned invention wherein the electrolyte is provided being accommodated in a container; said electrodes are provided being inserted into said electrolyte and electrically connectable to a load; a proton exchange membrane is providedwhich divides a space between said electrodes; said electrodes are illuminated by said illuminating means.
A further object of this disclosure is to disclose the abovementioned invention wherein the provided metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
A further object of this disclosure is to disclose the abovementioned invention wherein the per specific metal, said provided metal nanoparticles are distributed over sizes corresponding to maximum operability according to the spectral distribution of the light source.
A further object of this disclosure is to disclose the abovementioned invention wherein the said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template. A further object of this disclosure is to disclose the abovementioned invention wherein the size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
A further object of this disclosure is to disclose the abovementioned invention wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution. Similarly, a further object of this disclosure is to disclose the abovementioned wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NTPAM and acrylic acid, porous Polystyrene- polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution.
A further object of this disclosure is to disclose the abovementioned invention wherein a method of manufacturing of a fuel cell stack comprising the steps of (a) providing a plurality of n fuel cells manufactured where either n is an integer equal or greater 2 and (b) integrating said cells into a monoblock unit.
A further object of this disclosure is to disclose the abovementioned invention wherein a method of manufacturing of a electrolysis cell stack comprising the steps of (a) providing a plurality of n electrolysis cells as aforementioned,such that n is an integer equal or greater 2 and (b) integrating said cells into a monoblock unit.
A further object of this disclosure is to disclose the abovementioned invention wherein the step of illuminating said NPE comprises a step of collecting extraneous radiation.
A further object of this disclosure is to disclose the abovementioned invention wherein the step of illuminating said NPE comprises a step of sensing and adjusting said illuminating means.
A further object of this disclosure is to disclose the abovementioned invention wherein the said electrodes are disposed at an acute angle and illuminated by a scattering element disposed so that said extraneous radiation being incident on said scattering element is directed thereby onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation reflected by a reflecting surface operable for directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation reflected by a tapered conical surface operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation reflected by a parabolic surface operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation diffracted by a diffractive optical element operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
A further object of this disclosure is to disclose the abovementioned invention wherein the method comprises a step of illuminating said electrodes by radiation delivered by a planar diffracting element(insert) positioned adjacent to the electrode.
A further object of this disclosure is to disclose the abovementioned invention wherein NPE is characterized by metal nanoparticles a size distribution which is predefined to provide a maximum light induced effect in varied location, hight and time of the day.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to understand the invention and to see how it may electrical electric be implemented in practice, a plurality of embodiments is adapted to now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which
Fig. 1 presentsjncrement (%) vs Klux in Electrolysis Cells (EC) & Fuel Cells (FC), according to Tables IA and IB;
Fig. 2 is a schematic diagram of the photocatalytic electrode assembly
Fig. 3 is a schematic diagram of the photocatalytic electrolytic cell;
Fig. 4 is a schematic electric diagram of the photocatalytic electrode assembly apparatus;
Figs 5 and 6 are microphotographs of the surfaces of the photocathalytic electrodes coated with nanoparticles of silver and platinized titanium, respectively;
Fig. 7 is a schematic arrangement of the scattering elongate elements placed between photocathalytic electrodes;
Fig. 8 is a graph of the spectrum of plasmon resonance absorption of silver nanoparticles;
Fig. 9 is a graph of the spectrum of solar radiation;
Fig. 10 is a schematic optical arrangement of the light delivery system; and
Figs 1 Ia to l ie, 12a-b and 13 are alternative light delivery system embodiments.
DETAILED DESCRIPTION OF THE INVENTION
The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, are adapted to remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide an surface Plasmon resonance assisted photocatalytic apparatus and process.
The excitation of surface plasmons by light is denoted as a surface plasmon resonance (SPR) for planar surfaces or localized surface plasmon resonance (LSPR) for nanometer- sized metallic structures. This phenomenon is the basis of many standard tools for measuring adsorption of material onto planar metal (typically gold and silver) surfaces or onto the surface of metal nanoparticles. Surface plasmons, also known as surface plasmon polaritons, are surface electromagnetic waves that propagate in a direction parallel to the metal/dielectric (or metal/vacuum) interface. Since the wave is on the boundary of the metal and the external medium (air or water for example), these oscillations are very sensitive to any change of this boundary, such as the adsorption of molecules to the metal surface.
The term "illuminating means" hereinafter refers to an illuminating optical arrangement (lighter) having a portion collecting extraneous radiation and a portion delivering said solar radiation to said electrode surfaces.
The collecting portion can include focusing elements such as lenses, mirrors and other optical elements. An optical collimator used for concentration of extraneous radiation is in the scope of the current invention.
The term "light induced effect" hereinafter refers to the activation of a variety of phenomenon taking place on the electrode. Hence, in a non-limiting manner, the utilizable phenomena is excitation of surface plasmon resonance. It is thus in the scope of the invention wherein the excitation of surface plasmons by light is referring to a surface plasmon resonance (SPR) for planar surfaces or localized surface plasmon resonance (LSPR) for nanometer-sized metallic structures. It is acknowledged in this respect that surface plasmons (e.g., surface plasmon polaritons) are electromagnetic waves resonantly excited in surface or volume of metallic nano particles. The terms 'SPR' and 'LSPR' will interchangeably used in this patent. Since the wave is on the boundary of the metal and the external medium (air or water for example), these oscillations are very sensitive to any change of this boundary, such as the adsorption of molecules to the metal surface. It is further in the scope of the invention wherein localized surface plasmon polaritons (LSPR), are collective electron charge oscillations in metallic nanoparticles when excited by light. They are associated with enhanced near field at resonance and such a field is localized at the nanoparticle and decays away from the nanoparticle/dieletric interface into the dielectric background. Light intensity enhancement is a very important aspect of LSPR and localization means LSPR has very high spatial resolution (subwavelength) limited only by the size of nanoparticles. Some other physical properties such as magneto-optical effect are also enhanced by LSPR.
The term 'fuel cell' (FC) refers hereinafter to an electrochemical cell that converts a source fuel into an electrical current. The FC generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. The reactants flow into the cell, and the reaction products flow out of it, while the electrolyte remains within it. Fuel cells can operate virtually continuously as long as the necessary flows are maintained. Many combinations of fuels and oxidants are possible. A hydrogen fuel cell uses hydrogen as its fuel and oxygen (usually from air) as its oxidant. Other fuels include hydrocarbons and alcohols. Other oxidants include chlorine and chlorine dioxide. The fuel cells of the present invention are typically, yet not exclusively, made up of three segments which are sandwiched together: the anode, the electrolyte, and the cathode. It is in the scope of the invention wherein two chemical reactions occur at the interfaces of the three different segments. The net result of the two reactions is that fuel is consumed, water or carbon dioxide is created, and an electrical current is created, which can be used to power electrical devices, normally referred to as the load. It is also in the scope of the invention wherein at the anode a catalyst oxidizes the fuel, usually hydrogen, fuel into is turning a positively charged ion and a negatively charged electron. The electrolyte is a substance specifically designed so ions can pass through it, but the electrons cannot.. According to an embodiment of the invention, namely the archetypal hydrogen-oxygen proton exchange membrane fuel cell (PEMFC) design, a proton- conducting polymer membrane, (the electrolyte), separates the anode and cathode sides. On the anode side, hydrogen diffuses to the anode catalyst where it later dissociates into protons and electrons. These protons may react with oxidants causing them to become what is commonly referred to as multi-facilitated proton membranes. The protons are conducted through the membrane to the cathode, but the electrons are forced to travel in an external circuit (supplying power) because the membrane is electrically insulating. On the cathode catalyst, oxygen molecules react with the electrons (which have traveled through the external circuit) and protons to form water - in this embodiment, the only waste product, either liquid or vapor. In addition to this pure hydrogen type, there are hydrocarbon fuels for fuel cells, including diesel, methanol and chemical hydrides. The waste products with these types of fuel are carbon dioxide and water. The materials used in fuel cells differ by type. In a typical membrane electrode assembly (MEA), the electrode-bipolar plates are usually made of metal, nickel or carbon nanotubes, and are coated with a catalyst (like platinum, nano iron powders or palladium) for higher efficiency. Carbon paper separates them from the electrolyte. The electrolyte could be ceramic or a membrane. It is also in the scope of the invention wherein the fuel cell further comprises diaphragm, such as polysulfone or ceramic diaphragms.
It is in the scope of the invention wherein high temperature fuel cells are used. Hence for example, an NPE-based Solid oxide fuel cell (SOFC) is provided useful. SOFC is advantageous because of a possibility of using a wide variety of fuel". Below are the chemical equations for the reaction:
Anode Reaction: CH3OH + H2O → CO2 + 6H+ + 6e-
Cathode Reaction: 3/2 O2 + 6H+ + 6e- → 3H2O
Overall Reaction: CH3OH + 3/2 O2 → CO2 + 2H2O + electrical energy
At the anode SOFCs can use nickel or other catalysts to break apart the methanol and create hydrogen ions and CO2. A solid yttrium stabilized zirconium (YSZ) is used as the electrolyte.. The standard operating temperature is about 95O0C http://en.wikipedia.org/wiki/Fuel cell - cite note-sahibzada-12#cite note-sahibzada-12.
The term 'electrolysis cell' and 'electrolytic cell' (EC) interchangeably refers hereinafter to a cell decomposes chemical compounds by means of electrical energy, in an electrolysis process. The result is that the chemical energy is increased. It is in the scope of the invention wherein the electrolytic cell comprises three component parts: an electrolyte and two electrodes (a cathode and an anode). The electrolyte is usually a solution of water or other solvents in which ions are dissolved. Molten salts such as sodium chloride are also electrolytes. When driven by an external voltage applied to the electrodes, the electrolyte provides ions that flow to and from the electrodes, where charge-transferring, or faradaic, or redox, reactions can take place. Only for an external electrical potential (i.e., voltage) of the correct polarity and large enough magnitude can an electrolytic cell decompose a normally stable or inert chemical compound in the solution. The electrical energy provided undoes the effect of spontaneous chemical reactions. It is also in the scope of the invention wherein the cathode is the electrode to which cations flow (positively charged ions, like silver ions Ag+), to be reduced by reacting with (negatively-charged) electrons on the cathode. Likewise, anode is the electrode to which anions flow (negatively charged ions, like chloride ions Cl-), to be oxidized by depositing electrons on the anode. Thus positive electric current flows from the cathode to the anode. To an external wire connected to the electrodes of a battery, thus forming an electric circuit, the cathode is positive and the anode is negative.
The term "collimator" hereinafter refers to a device adapted to change a cross section of a light beam. The collimator comprises at least two confocally placed focusing elements (lenses, mirrors, diffraction optical elements.
The term 'coated' or 'coating' is interchangeably refer hereinafter to a step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically attaching, adsorbing or otherwise adding metal nanoparticles to said electrode. Reference is now made to Fig. 2, presenting Increment (%) vs Klux in Electrolysis Cells (EC) & Fuel Cells (FC), according to Tables IA and IB. The term 'article of manufacture" refers to one or more of the following: means which provides power for base stations or cell sites; Off-grid power supply; Distributed generation; Fork Lifts; Emergency power systems are a type of fuel cell system, which may include lighting, generators and other apparatus, to provide backup resources in a crisis or when regular systems fail. They find uses in a wide variety of settings from residential homes to hospitals, scientific laboratories, data centres, telecommunication equipment and modern naval ships; An uninterrupted power supply (UPS) provides emergency power and, depending on the topology, provide line regulation as well to connected equipment by supplying power from a separate source when utility power is not available; Unlike a standby generator, it can provide instant protection from a momentary power interruption; Base load power plants; Electric and hybrid vehicles.; Notebook computers for applications where AC charging may not be available for weeks at a time; Portable charging docks for small electronics (e.g. a belt clip that charges your cell phone or PDA); Smartphones with high power consumption due to large displays and additional features like GPS might be equipped with micro fuel cells; Small heating appliances; vehicle, satellite, air craft, marine and vessel, means of transportation, means of generating electricity and power source, engine, fork lifts, hydrogen fuelling stations, buildings, domestic buildings, hydrogen storage for alternative energy utilizations such as solar, wind, nuclear, hydro etc.
Reference is now made to Fig. 2, presenting different embodiments of the electrode arrangement . Specifically, anodes 121 and cathodes 124 are separated by a separator 122 and a proton exchange membrane 123.
Reference is now made to Fig. 3, presenting a schematic diagram of the EC/FC 100. The aforesaid EC/FC 100 comprises a container 20 comparted into two compartments by a proton exchange membrane 30. The photocatalytic electrodes 50 are inserted into the container 20 filled an electrolyte. The electrodes 50 are barred or seperated from each other by means of separators 40. A light concentrator 10 is adapted to concentrate the extraneous radiation 140. The concentrated radiation is delivered to the electrodes 50 by means of optical fibers 70 and scattering elements 80. The photocathalytic electrodes 50 are electrically connected to a voltage source 60. The photocathalytic electrodes 50 are coated with metal nanoparticles operable for localized surface plasmon resonance induced by said illumination being incident onto electrolysis electrode surfaces coated with metal nanoparticles.
In an unlimited manner, the photocatalytic cell includes a pair of electrodes 50 (3 cm x 100 cm). The aforesaid photocatalyic cells can be grouped into an array.
The term " proton exchange membrane" or "polymer electrolyte membrane" (PEM) refers to a semi-permeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen. This is their essential function when incorporated into a membrane electrode assembly (MEA) of a proton exchange membrane fuel cell or of a proton exchange membrane electrolyser : separation of reactants and transport of protons. PEMs can be made from either pure polymer membranes or from composite membranes where other materials are embedded in a polymer matrix. One of the most common and commercially available PEM materials is Nation, a DuPont product. While Nafion is an ionomer with a perfluorinated backbone like Teflon, there are many other structural motifs used to make ionomers for proton exchange membranes. Many use polyaromatic polymers while others use partially fluorinated polymers. Hence for example, the membrane is a proton exchange membrane, a ceramic diaphragm or other separating media like polysulphone and other membranes for separation of gases generated by the apparatus
LSP are collective electronic excitations near the surface of metallic particles nanoparticles. A resonance wavelength increases with a size of nanoparticles. It is known that optical excitation of plasmon resonances in metallic nanoparticles results in an enhanced local electromagnetic field around the particles. The field distribution depends on the particle parameters such as size, shape, optical constants and surrounding dielectric medium.
Excitation of LSP near the resonance wavelength generates a large enhancement of the local electric field in the vicinity of the metal particle. The enhancement of the order of 105 has been reported for the silver particles of 100 nm size.
When a molecule of the compound to be electrolyzed is in vicinity of the surface of the nanoparticle in which LSPs are excited, electromagnetic interaction between molecular dipole and LSP resonance field will results in more effective electrolysis. Specifically, the disclosed approach is applied to water electrolysis. This is advantageous in that when the nanoparticle coated electrodes are illuminated by the radiation of the wavelength corresponding to LSP resonance, the same hydrogen amount will be dissociated at less energy consumption in comparison with non illuminated electrodes known in the art . In corollary the electrodes of the present invention provide a greater amount of hydrogen at the same energy consumption, compared to the prior art non illuminated electrodes.
Reference is now made to Fig. 4, presenting a photocatalytic electrode assembly 115 comprising cathodes and anodes 120 and 125 connected to the voltage source 60 in parallel.
Reference is now made to Figs 5 and 6, presenting electron microscope images of electrodes coated with silver nanoparticles and platinised titanium, respectively. The silver nanoparticles have sizes ranging between 50 and 300 nm.
In accordance with one embodiment of the current invention, the metal nanoparticles are immobilized on a surface of electrode by means of a porous gel template. The porous gel template is made of a gel based on agarose, polyacrylamide or other like compounds.
Reference is now made to Fig. 7, presenting an arrangement of the EC/FC. Elongate optical elements 130 are inserted into a space between the photocathalytic electrodes 120. The optical elements 130 constitute rods of square or rectangular cross-section. Side surfaces of the rods are sanded such that they scatter the light provided to them. Thus, the optical elements 130 provide sufficiently uniform illumination of surfaces of the photocathalytic electrodes 120.
Reference is now made to Figs 8 and 9, presenting spectrum of plasmon resonance absorption of silver nanoparticles and solar radiation spectrum. One can readily see correspondence between the aforesaid spectra. In other words, illumination of the photocathalytic electrodes can be performed by collected solar radiation.
Reference is now made to Fig. 10, presenting an optical arrangement of the lighter 200. The aforesaid lighter 200 comprises two collimator lenses 150 and 160, fiber-optic taper 170, light-guide fiber 180 and elongate optical element 130. A parallel beam of solar radiation 140 is narrowed down by the lens 150 and 160. Then, the narrowed beam is inserted into the light-guide fiber 180 by means of the taper 170. The fiber 180 delivers the solar radiation to the elongate optical element 130 which is placed in the space between the photocathalytic electrodes 120 (not shown). Radiation 135 scattered on side surface of the optical element 130 is operable to excite plasmon resonance. As described above, the most advantage of the current invention is that when the nanoparticle coated electrodes are illuminated by the radiation of the wavelength corresponding to LSP resonance, the same hydrogen amount will be dissociated at less energy consumption in comparison with electrodes known in the art without illumination or greater amount of hydrogen will be provided at the same energy consumption. Comparing Fig. 5 with Fig. 6, we can see that the solar radiation spectrum is very satisfactory for excitation of LSP resonance.
Reference is now made to Figs 11a to l ie, presenting alternative embodiments of the light delivery arrangements. Specifically, in Fig 11a, electrodes 120 are disposed at an acute angle. A scattering element 131 is disposed so that said extraneous radiation 140 being incident on the scattering element 131 is scattered thereby onto the electrodes 120.
In Fig. l ib, a reflecting surface 132 is operable for directing said radiation onto said electrodes. In Fig. l ie, a tapered reflecting conical surface 133 is operable for concentrating extraneous radiation 140 and directing said radiation onto said electrodes 120.
In Fig Hd, a parabolic reflecting surfacel33 is operable for concentrating extraneous radiation 140 and directing said radiation onto the electrodes 120.
In Fig. l ie, a diffractive optical element 134 is operable for concentrating extraneous radiation 140 and directing the radiation onto the electrodes 120.
Reference is now made to Fig. 12a, presenting an alternative embodiment of light delivering arrangement comprising a bundle of optical fibres 180 carrying the extraneous radiation to the electrodes 120 and 125. Optical fibres 136 are inserted between the electrodes 120 and 125 and operable for scattering the aforesaid radiation in direction of the electrodes 120 and 125. Fig. 12b is the same, wherein optical fibres 136 are set adjacent the electrode as a net or crossed array of fibres. Reference is now made to Fig. 13, presenting an alternative embodiment of spacer 40. The extraneous radiation 140 enters into the spacer 40. Then, the radiation 135 scattered at side surfaces of the spacer 40 illuminates the neighbouring electrode 120.
EXAMPLE 1
Silver metal electrodes were coated by colloidal Ag with particles size 50-300nm by means of photocathalytic deposition from 0.1% solution Of AgNO3 under the following conditions: cathode - Ag; anode - Ag; Voltage = 4V; Current = 0.1A; time = 3min
A water electrolysis cell was assembled using two coated Ag electrodes (50x50mm) with a distance between electrodes of 50mm. Electrolysis of 0.1% water solution of KOH (50ml) was initiated by applying an external voltage under extraneous illumination. A Halogen -light source (30W) was employed for the illumination of the nanoparticle coated electrode.
A comparison of the onset of electrolysis by measuring the electrolysis current and observing the onset of gas bubble generation on the electrode surface under illumination as compared to non-illuminated electrode showed that under illumination gas bubbles were generated at a voltage of 0.75 volt vs. 1.3 V without illumination.
EXAMPLE 2
Raw material is colloidal Au (SIGMA 636347). Particles of size lOOnm were deposited on a gold electrode by welding in argon atmosphere on the Au surface. Electrolysis experiments were performed in a cell consisting of two Au electrodes (50x5 Omm). The distance between electrodes was 50mm. The electrolyte was 0.1% water solution of KOH (50ml). The electrolysis initiation under illumination (3OW halogen lamp) was at the voltage of 0.8 V. EXAMPLE 3
An electrode assembly as shown in Fig 1 was photocathalytically coated with silver nano particles as described in Example 1. The particle distribution over sizes is presented in Fig 2.
Amounts of gas generated on the electrode assembly were measured at a number of values of the voltage applied to the electrode assembly. The amounts of the gas generated on illuminated and non-illuminated assembly are compared, as well. 15 % solution of potassium sulphate (K2SO4) in double distilled water was used as an electrolyte. The optical arrangement shown in Fig. 7 was used for illuminating the photocathalytic electrodes. In the current example a number of halogen lamps were used as a light source instead of solar radiation. The lack of UV radiation in the emission spectrum of halogen lamps in comparison with the solar radiation should be noted.
The illuminance was measured at the output surface of the light guide by using a commercial photometer. The illuminances used in this experiment were 60kLux and 105 kLux approximately simulating the intensity of non concentrated solar light and twice concentrated solar light intensity.
The results are presented in Table Ia and Ib.
Table Ia. Gas generation with silver coated electrode at the illuminance of 60 kLux,
Figure imgf000029_0001
Table Ib. Gas generation with silver coated electrodes at the illuminance of 105 kLux,
Figure imgf000030_0001
Reference is made now to Fig. 1 which presentsjncrement (%) vs Klux in Electrolysis Cells (EC) & Fuel Cells (FC), according to Tables IA and IB above.
EXAMPLE 4
Titanium electrodes electroplated with 2 micron thick platinum (purchased from Ti Anode Fabricators Pvt. Ltd., Chennai, India) exhibited nano structured features as shown in Fig.3. The electrodes lOmmxlOOmm were mounted in the photocathalytic cell.
The results obtained at illuminance 100 kLux and without illumination are presented in Table 2.
Table 2. Gas generation with titanium coated electrodes
Figure imgf000031_0001
EXAMPLE 5
An electrode-containing cell (either FC or EC), at least partially coated by metal nanoparticles (NPE), characterized by a light induced effect, comprising at least one fluidized bed located nearby at least one electrode; fluidized bed comprises said photocatalytic nanoparticles.
EXAMPLE 6
Optimal size distribution of the nanoparticles is obtained by various techniques, namely: gel template; chemical deposition and reduction, and spray pyrolysis.
EXAMPLE 7
The electrical efficiency of fuel cell is found to be more than 2.5% increase of electrical efficiency compared with (standard-) non-illuminated electrodes.

Claims

Claims:
1. An electrode, at least partially coated by metal nanoparticles (NPE), characterized by a light induced effect.
2. A photocatalytic reactor characterized by having at least one NPE of claim 1.
3. A photocatalytic reactor characterized by having at least one light- illuminated NPE of claim 1, said illumination provided either directly or indirectly.
4. A photocatalytic reactor characterized by having at least one solar light- illuminated NPE of claim 1, said illumination provided either directly or indirectly.
5. The light-illuminated NPE of claim 3, useful for inducing plasmon surface resonance (PSR).
6. The solar light -illuminated NPE of claim 4, useful for inducing plasmon surface resonance (PSR).
7. A light assisted fuel cell characterized by having at least one light- illuminated NPE of claim 1.
8. A solar light assisted fuel cell characterized by having at least one solar- illuminated NPE of claim 1.
9. A light assisted electrolysis cell characterized by having at least one light- illuminated NPE of claim 1, said illumination provided either directly or indirectly
10. A solar light assisted electrolysis cell characterized by having at least one solar-illuminated NPE of claim 1, said illumination provided either directly or indirectly.
11. NPE of claim 1, characterized by more than 5% reduction in energy consumption (KWh electric/mole H2) compared with a non-light illuminated or non-nanoparticles coated electrodes.
12. A fuel cell of claim 7, characterized at least one of the following: (α) more than 2.5% increase of electrical efficiency compared with a non- illuminated electrodes.
13. A electrolysis cell of claim 9, characterized by at least one of the following: (a) more than 5% reduction in electric energy consumption (KWh /mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes.
14. A electrolysis cell of claim 9, characterized by at least one of the following: (a) more than 5% reduction in electric energy consumption (KWh /mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes; The fuel cell of claim 7 characterized by:
(a) an electrolyte; and
(b) at least one electrode in connection with said electrolyte; wherein at least one of the following is being held true:
(1) said electrode is at least partially coated by metal nanoparticles (NPE);
(2) said electrode is characterized by light induced effect;
(3) Increment (%) vs Klux plot as defined in Fig. 1 is 0.1 or more; or,
(4) said electrode increases more than 2.5% electrical power generation compared with a non-illuminated or non-nanoparticles coated electrodes.
15. The fuel cells of claim 14, additionally comprising illuminating means adapted to provide at least one of the following: light collector, light delivering means, and electrode illuminator.
16. The fuel cells of claim 11, wherein said illuminating means comprises at least one element selected from a group consisting of scatterers, lenses, optic fibres, stripped optic fibers, light guide, mirrors, transparent electrode's separators, semitransparent electrodes, diffractive optical elements and any combination thereof.
17. The fuels cells of claim 14 wherein said electrolyte is accommodated in a container; said electrodes are inserted into said electrolyte and electrically connectable to a load; a space between said electrodes is divided by means of a separating membrane; said electrodes are illuminated by said illuminating means.
18. The electrolysis cells of claim 6, characterized by:
(a) an electrolyte; and
(b) at least two electrodes in connection with said solution; wherein at least one of the following is being held true:
(1) at least one of said electrodes is at least partially coated by nanoparticles (NPE);
(2) at least one of said electrodes is characterized by light induced effect;
(3) Increment (%) vs Klux plot as defined in Fig. 1 is 0.1 or more; or,
(4) said electrode reduces, by more than 5%, the electrolysis cell's energy consumption (KWh/mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes;
19. The electrolysis cells of claim 18, additionally comprising illuminating means adapted to provide at least one of the following: light collector, light delivering means, and electrode light illuminator.
20. The electrolysis cells of claim 19, wherein said illuminating means comprises at least one element selected from a group consisting of scatterers, lenses, optic fibres, stripped optic fibers, light guide, mirrors, transparent electrode's separators, transparent electrodes, diffractive optical elements and any combination thereof.
21. The electrolysis cells of claim 18wherein said electrolyte is accommodated in a container; said electrodes are inserted into said electrolyte and electrically connectable to a voltage source; a space between said electrodes is divided by means of a separating membrane; said electrodes are illuminated by said illuminating means.
22. The NPE of claim 1, wherein said metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
23. The cells according to either one of claims 13-22, wherein said metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
24. The NPE according to claim 22, wherein, per specific metal, said metal nanoparticles are distributed over sizes corresponding to maximum operability according to the spectral distribution of the light source.
25. The cells according to either one of claims 13-22, wherein, per specific metal, said metal nanoparticles are distributed over sizes corresponding to maximum operability according to the spectral distribution of the light, source.
26. An NPE according to claim 22 wherein said size distribution is obtained by: spraying, spin coating, ink jet, chemical deposition all characterized by pre prepared size distribution.
27. An NPE according to claim 22 wherein said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
28. The cells according to claim 23, wherein said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
29. The NPE according to claim 24, wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution.
30. The cells according to claim 25, wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution.
31. A fuel cell stack characterized by having a plurality of n fuel cells according to either one of claims 14 or 15, n is an integer equal or greater
2.
32. An electrolysis cell stack characterized by having a plurality of n fuel cell according to either one of claims 17 or 18 n is an integer equal or greater 2.
33. The cells according to either one of claims 15 or 18, wherein said illuminating means comprising a collecting extraneous radiation portion.
34. The cells according to claim 27, wherein said illuminating means further comprising a delivering means portion adapted to deliver said solar radiation to said NPE surfaces.
35. The cells according to either one of claims 32 or 33 wherein said illuminating means comprising light sensing means
36. The cells according to claim 33, wherein said collecting portion additionally comprising at least one optical element selected from the group consisting of lens, reflecting element, a curvilinear mirror, diffractive optical element and any combination thereof.
37. The cells according to claim 33, wherein said collecting portion comprises an optical collimator.
38. The cells according to claim 33, wherein said delivering means comprises at least one selected from a taper, a light-guide, fibres.
39. The cells according to claim 33, wherein said electrode illuminator comprises scattering optical element, planar light scattering insert and a multifiber scatteing element.
40. The cells according to either one of claims 15 or 17, wherein said illuminating means is a transparent polymer.
41. The cells according to claim 40, wherein said transparent polymer is selected from a group consisting of polycarbonates, poly(methyl metaacrylates) (PMMA, e.g., Lucite, or Perspex) and derivatives thereof.
42. An article of manufacture comprising at least one electrode characterized by being at least partially coated by nanoparticles (NPE).
43. The cells according to either one of claims 12-22, wherein said electrodes are disposed at an acute angle; a scattering element is disposed so that said extraneous radiation being incident on said scattering element is scattered thereby onto said electrodes.
44. The cells according to either one of claims 12-22, comprising a reflecting surface operable for directing said radiation onto said electrodes.
45. The cells according to either one of claims 12-22, comprising a tapered conical reflecting surface operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
46. The cells according to either one of claims 12-22, comprising a parabolic reflecting surface operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
47. The cells according to either one of claims 12-22, comprising a diffractive optical element operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
48. The article of manufacture refers hereinafter vehicle, satellite, air craft, marine and vessel, means of transportation, means of generating electricity and power source, engine, fork lifts, hydrogen fuelling stations, buildings, domestic buildings, hydrogen storage for alternative energy utilizations such as solar, wind, nuclear, hydro etc.
49. A method for producing at least partially coated electrode, wherein said method comprising steps of:
(a) providing an electrode;
(b) at least partially coating said electrode with by metal nanoparticles (NPE), having predetermined size distribution; wherein said size distribution of said metal nanoparticles is adapted for maximal light absorption and for optimal localized surface plasmon polarization (LSPR) with the visible optical spectrum used for illumination.
50. The method of claim 44, wherein said step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically attaching, adsorbing or otherwise adding metal nanoparticles to said electrode.
51. A method for producing a light induced electrode, wherein said method comprising steps of:
(a) providing an electrode; and
(b) at least partially coating said electrode with by metal nanoparticles (NPE), having predetermined size distribution; thereby providing a light induced NPE.
52. The method of claim 51, wherein said step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically etching, adsorbing or otherwise adding metal nanoparticles to said electrode.
53. A method for producing a photocatalytic reactor, wherein said method comprising steps of: (a) providing an electrode;
(b) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; thereby providing a light induced NPE.
54. The method of claim 53, wherein said step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically attaching, adsorbing or otherwise adding metal nanoparticles to said electrode.
55. The method of claim 54, useful for inducing plasmon surface resonance (PSR).
56. A method for producing a fuel cell, wherein said method comprising steps of:
(a) providing an electrolyte;
(b) providing at least one electrode in connection with said solution;
(c) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; such that at least one of the following is being held true: wherein at least one of the following is being held true:
(1) said electrode is at least partially coated by nanoparticles (NPE);
(2) said electrode is characterized by light induced effect; or,
(3) said electrode increases, by more than 2.5%, the electrical power generation compared with a non-solar illuminated or non-nanoparticles coated electrodes.
57. The method of claim 56, wherein said step of coating is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically etching, adsorbing or otherwise adding metal nanoparticles to said electrode.
58. The method of claim 56, additionally comprising step of providing illuminating means for enabling at least one of the following: light collector, light delivering means, and electrode light illuminator.
59. A method for producing a electrolysis cell, wherein said method comprising steps of:
(a) an electrolyte;
(b) providing at least one electrode in connection with said electrolyte;and
(c) at least partially coating said electrode with by nanoparticles (NPE), having predetermined size distribution; such that at least one of the following is being held true: wherein at least one of the following is being held true:
(1) said electrode is at least partially coated by nanoparticles (NPE);
(2) said electrode is characterized by light induced effect; or,
(3) said electrode reduces, by more than 5%, the electrolysis cell's electric energy consumption (KWh/mole H2) compared with a non-solar illuminated or non-nanoparticles coated electrodes.
60. The method of claim 59, wherein said step of coating is is further characterized by step or steps selected from a group consisting of doping, immersing, gluing, depositing, soaking, adding, precipitating, seeding, sintering, covalently or ionically etching, adsorbing or otherwise adding metal nanoparticles to said electrode.
61. The method of claim 60, additionally comprising step of providing illuminating means for enabling at least one of the following: light collector, light delivering means, and electrode light illuminator.
62. A method of photocatalysis in electrolysis cells comprising the steps of (a) providing a fuel cell further comprising i. an electrolyte; and ii. at least one electrode in connection with said solution; said electrode is at least partially coated by metal nanoparticles (NPE);
(b) illuminating said electrodes with extraneous radiation; wherein said method further comprises a step of light inducing effect do that Increment (%) vs Klux plot as defined in Fig. 1 is 0.1 or more; or said electrode reduces, by more than 5%, of the electrolysis cell's electrical energy consumption kWh/mole H2 compared with a non-solar illuminated or non- nanoparticles coated electrodes.
63. The method of claim 62, wherein said step of illuminating is performed by illuminating means comprising at least one of the following: light collector, light delivering means, and electrode light illuminator.
64. The method of claim 63, wherein said illuminating means comprises at least one element selected from a group consisting of scatterers, lenses, optic fibres, mirrors, transparent electrode's separators, semitransparent electrodes, diffractive optical elements and any combination thereof
65. The method of claim 62 wherein said electrolyte provided being accommodated in a container; said electrodes are are provided being inserted into said electrolyte and electrically connectable to a load; a proton exchange membrane is provided being divides a space between said electrodes; said electrodes are illuminated by said illuminating means.
66. A method of photocatalysis in fuel cells comprising the steps of (a) providing a fuel cell further comprising i. an electrolyte; and ii. at least one electrode in connection with said solution; said electrode is at least partially coated by metal nanoparticles (NPE); and (b) illuminating said electrodes with extraneous radiation; wherein said method further comprises a step of light inducing effect do that Increment (%) vs Klux plot as defined in Fig. 1 is 0.1 or more; or said electrode increases by more than 2.5%, the fuel cell's energy output compared with a non-solar illuminated or non-nanoparticles coated electrodes.
67. The method of claim 66, wherein said step of illuminating is performed by illuminating means comprising at least one of the following: light collector, light delivering means, and electrode light illuminator.
68. The method of claim 67, wherein said illuminating means comprises at least one element selected from a group consisting of scatterers, lenses, optic fibres, mirrors, transparent electrode's separators, semitransparent electrodes, diffractive optical elements and any combination thereof
69. The method of claim 66 wherein said electrolyte provided being accommodated in a container; said electrodes are are provided being inserted into said electrolyte and electrically connectable to a load; a proton exchange membrane is provided being divides a space between said electrodes; said electrodes are illuminated by said illuminating means.
70. The method of claim 49, wherein said provided metal nanoparticles are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
71. The method according to either one of claims 62-69, wherein said provided nanoparticals comprise metal nanoparticles which are selected from the group consisting of gold, silver, platinum, copper, titanium, chromium and any combination thereof.
72. The method according to claim 49 wherein, per specific metal, said provided metal nanoparticles are distributed over sizes according to a spectral distribution required for inducing illumination such that a maximum operability is provided.
73. The method according to either one of claims 62-69, wherein, per specific metal, said provided metal nanoparticles are distributed over sizes according to a spectral distribution required for inducing illumination such that a maximum operability is provided.
74. An method according to claim 73, wherein said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
75. The method according to claim 74, wherein said size distribution is obtained by chemical deposition of said nano particles on or within a porous gel template.
76. The method according to claim 75, wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution.
77. The method according to claim 76, wherein the porous gel template is made of a gel based on agarose, polyacrylamide,copolymer of agarose and polyacrylamide, N-isopropyl acrylamide hydrogel (NIPAM), mixture of NIPAM and acrylic acid, porous Polystyrene-polybutadiene block copolymer, Polystyrene-divinyl benzene and other porous structures with nanometer pore distribution
78. A method of manufacturing of a fuel cell stack comprising the steps of
(a) providing a plurality of n fuel cells manufactured according claim 57 to either n is an integer equal or greater 2 and
(b) integrating said cells into a monoblock unit.
79. A method of manufacturing of a electrolysis cell stack comprising the steps of (a) providing a plurality of n electrolysis cells manufactured according claim 57 to either n is an integer equal or greater 2 and
(b) integrating said cells into a monoblock unit.
80. The method according to either one of claims 57 or 61, wherein said step of illuminating said NPE comprises a step of collecting extraneous radiation.
81. The method according to claim 80, wherein said illuminating means further comprising a delivering means portion adapted to deliver said solar radiation to said NPE surfaces.
82. The method according to either one of claims 80 or 81, wherein said step of illuminating said NPE comprises a step of phototropically adjusting said illuminating means.
83. The method according to claim 82, wherein said collecting portion additionally comprising at least one optical element selected from the group consisting of lens, a curvilinear mirror, diffractive optical element and any combination thereof.
84. The method according to claim 83, wherein said collecting portion comprises an optical collimator.
85. The method according to claim 82, wherein said delivering portion comprises at least one selected from a taper, a light-guide fibre and an elongate surface scattering optical element configured for placement thereof in a gap between electrodes and illumination thereof or any combination of the same.
86. The method according to claim 82 wherein said delivering portion additionally comprising a scattering optical element.
87. The method according to either one of claims 63 or 67, wherein said illuminating means is a transparent polymer.
88. The method according to claim 87, wherein said transparent polymer is selected from a group consisting of polycarbonates, poly(methyl metaacrylates) (PMMA, e.g., Lucite, or Perspex) and derivatives thereof.
89. An article of manufacture comprising at least one electrode characterized by being at least partially coated by nanoparticles (NPE).
90. The method according to either one of claims 12-22, wherein said electrodes are disposed at an acute angle; a scattering element is disposed so that said extraneous radiation being incident on said scattering element is scattered thereby onto said electrodes.
91. The method according to either one of claims 62-69, comprising a reflecting surface operable for directing said radiation onto said electrodes.
92. The method according to either one of claims 62-69, comprising a tapered conical surface reflecting operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
93. The method according to either one of claims 62-69, comprising a parabolic surface reflecting operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
94. The method according to either one of claims 62-69, comprising a diffractive optical element operable for concentrating extraneous radiation and directing said radiation onto said electrodes.
95. The NPE according to claim 1, wherein the size distribution of the metal nanoparticles is predefined to provide a maximum light induced effect in varied location, high and time of the day.
96. The fuel cell according to claim 9 wherein the size distribution of the metal nanoparticles is predefined to provide a maximum light induced effect in varied location, high and time of the day.
97. The electrolysis cell according to claim 10, wherein the size distribution of the metal nanoparticles is predefined to provide a maximum light induced effect in varied location, high and time of the day.
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