EP3695028A1 - Charges d'échangeurs d'anions pouvant être traversées pour une fente d'électrolyte dans l'électrolyse de co2 pour une meilleure répartition spatiale du dégagement gazeux - Google Patents

Charges d'échangeurs d'anions pouvant être traversées pour une fente d'électrolyte dans l'électrolyse de co2 pour une meilleure répartition spatiale du dégagement gazeux

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Publication number
EP3695028A1
EP3695028A1 EP18810945.8A EP18810945A EP3695028A1 EP 3695028 A1 EP3695028 A1 EP 3695028A1 EP 18810945 A EP18810945 A EP 18810945A EP 3695028 A1 EP3695028 A1 EP 3695028A1
Authority
EP
European Patent Office
Prior art keywords
salt bridge
cathode
exchange membrane
solid
bridge space
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP18810945.8A
Other languages
German (de)
English (en)
Inventor
Bernhard Schmid
Günter Schmid
Christian Reller
Dan Taroata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP3695028A1 publication Critical patent/EP3695028A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
    • C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B13/00—Diaphragms; Spacing elements
    • C25B13/02—Diaphragms; Spacing elements characterised by shape or form
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B3/00—Electrolytic production of organic compounds
    • C25B3/20—Processes
    • C25B3/25—Reduction
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B3/00—Electrolytic production of organic compounds
    • C25B3/20—Processes
    • C25B3/25—Reduction
    • C25B3/26—Reduction of carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms

Definitions

  • the present invention relates to an electrolytic cell having a multi-chamber structure, wherein a first ion exchange membrane comprising an anion exchanger adjoins a cathode space, wherein a salt bridge space adjoins this first ion exchange membrane, which comprises a solid Anione exchanger; an electrolysis plant with such an electrolysis cell; and a method for the electrolysis of CO2 using such an electrolytic cell or electro lysestrom.
  • CO2 is converted into carbohydrates by photosynthesis. This temporally and on a molecular level spatially divided into many sub-steps process is very difficult to copy on an industrial scale.
  • the currently more efficient way compared to pure photocatalysis is the electrochemical reduction of CO2.
  • a mixed form is the light-assisted electrolysis or the electrically assisted electrolysis. supported photocatalysis. Both terms are synonymous to use the, depending on the perspective of the beholder.
  • Electrolysis processes have evolved significantly in recent decades. For example, the PEM water electrolysis could be optimized to high current densities. Large electrolyzers with outputs in the megawatt range are introduced to the market.
  • the cathode compartment is usually limited by an AEM.
  • cathodically generated anions such as HCCg, CCg 2 , OH can be transported away in the direction of the anode.
  • HCCg, CCg 2 , OH can be transported away in the direction of the anode.
  • the sources mentioned vary greatly. Common to them, however, is a region between the AEM, which delimits the cathode space, and the Ano de, which contains a strongly acidic medium or protons he testifies, in which HCO3, CO3 2 are decomposed by protonation to CO2.
  • the charge transport in all these cells can be carried out in sections by different charge carriers. In contrast to other electrochemical structures, the charge carriers are usually not exchanged between the half cells, but destroyed in the additional gap between them.
  • the central gap contains only strongly acidic media.
  • the release of the CO2 is therefore usually carried out directly on the surface of the AEM, wherein in US2017037522A1 the medium of the gap is fixed, while it is liquid in DE 102017211930.6.
  • the surface of the AEM can be heavily loaded with gas bubbles, which can lead to a partial isolation of the membrane and thus to higher electrical losses in the cell.
  • a direct contact of strongly acidic solid media with the AEM should also be avoided since the solid media can not escape the CO2 released at this pH limit.
  • the inventors have found that with an additional electrolyzer component in particular the cell voltage, the operational stability and the energy efficiency can be improved.
  • this component is preferably inte grated so that in the resulting entire cell neither salt encrustations of the electrodes nor CO2 development in the anode space are possible.
  • the present invention represents a significant improvement of previously disclosed cell concepts.
  • a salt bridge space in an electrolysis cell with a solid anion exchanger which comprises at least in the vicinity of the cathode / AEM an, for example bicarbonate, carbonate and / or hydroxide conductive, for example, strongly basic Anionenaus exchanger.
  • the anion exchanger leads to the fact that a gas evolution, for example the CO 2 evolution in CO 2 electrolysis, can be distributed in the salt bridge space into the volume and does not take place only at the AEM salt bridge space interface.
  • anion exchanger and anion transporter are used interchangeably.
  • the transport function is characterized in that the anion exchange / anion cations that compensate for the charge of the anions.
  • the anion per se is, according to certain embodiments, only so easily bound that a dynamic exchange is made possible, thus providing a transport path for the anion in the electrolyte.
  • the cation is immobilized on the polymer back wheel of the anion exchange material, so that it itself can not participate in charge transport processes.
  • the present invention relates to an electrolytic cell comprising
  • a cathode compartment comprising a cathode
  • a first ion exchange membrane containing an anion exchanger and adjacent to the cathode compartment, the cathode contacting the first ion exchange membrane;
  • an anode compartment comprising an anode
  • the salt bridge space further comprising a salt bridge space, wherein the salt bridge space between the first ion exchange membrane and the first separator is arranged, wherein the salt bridge space comprises a solid anion exchanger which is at least partially in contact with the first ion exchange membrane.
  • an electrolysis plant comprising an electrolysis cell according to the invention.
  • the present invention is directed to a process for the electrolysis of CCg, wherein an electrolytic cell or an electrolysis plant according to the invention is used, wherein CCg is reduced at the cathode and at the cathode resulting bicarbonate and / or Carbo nat through the first ion exchange membrane to an electric lyten in the salt bridge space, wherein the bicarbonate and / or carbonate also by the solid anion exchanger transported in the salt bridge space away from the first ion exchange membrane.
  • Yet another aspect of the present invention relates to the use of an electrolysis cell according to the invention or an electrolysis plant according to the invention for the electrolysis of CO2 and / or CO.
  • FIGS 1 to 9 show schematically possible embodiments of an electrolytic cell according to the invention.
  • FIG. 10 schematically shows, by way of example, an electrolysis plant according to the invention.
  • Quantities in the context of the present invention are based on wt. %, unless otherwise stated or obvious from the context.
  • the weights complement each other.
  • % Shares to 100 wt. %.
  • hydrophobic is water-repellent. Hydrophobic pores and / or channels according to the invention are therefore those which repel water. In particular, hydrophobic properties are associated according to the invention with substances or molecules with nonpolar groups.
  • Gas diffusion electrodes in general are electrodes in which liquid, solid and gaseous phases are present, and where, in particular, a conductive catalyst catalyzes an electrochemical reaction between the liquid and the gaseous phase ka.
  • the embodiment can be of different nature, for example, as a porous "solid catalyst" with possibly auxiliary layers for adjusting the hydrophobicity, in which case for example a membrane-GDE composite, eg AEM-GDE composite, can be produced, as a conductive porous support, on which a catalyst can be applied in a thin layer, in which case again a membrane-GDE composite, eg AEM-GDE composite, can be produced, or as a composite porous catalyst, optionally with an additive directly on a membrane, eg AEM, can be applied and then in combination can form a catalyst coated membrane (CCM).
  • the normal pressure is 101325 Pa 1, 01325 bar.
  • Electro-osmosis is an electrodynamic phenomenon in which a force towards the cathode acts on particles in solution with a positive zeta potential and a force acts on the anode on all particles with a negative zeta potential. If conversion takes place at the electrodes, i. flows a galvanic current, so it comes also to a stream of particles with positive zeta potential for Ka method, regardless of whether the species is involved in the implementation or not. The same applies to a negative zeta potential and the anode. If the cathode is porous, the medium is also pumped through the electrode. It is also known as an electro-osmotic pump.
  • the material flows caused by electro-osmosis can also flow in opposite directions to concentration gradients. Diffusion-related currents that balance the concentration gradients can thereby be overcompensated.
  • the present invention relates to an electrolytic cell comprising
  • a cathode compartment comprising a cathode
  • a first ion exchange membrane containing an anion exchanger and adjacent to the cathode compartment, the cathode contacting the first ion exchange membrane;
  • an anode compartment comprising an anode
  • the salt bridge space is not particularly limited insofar as it corresponds to the first ion exchange membrane at least partially, in particular mechanically and / or ionically, to close, so that the solid anion exchanger in this can be at least partially in contact with the first ion exchange membrane.
  • the solid anion exchanger is in contact with the first ion exchange membrane at least substantially in a region in which the cathode contacts the first ion exchange membrane on an opposite side of this membrane, or in an area that is larger.
  • This allows a good Wei ter ein of anions, which are generated in the cathode and passed through the first ion exchange membrane, si cheriques.
  • the term "with the first Ionenaustau shear membrane in contact” does not exclude that the contact is not full-surface, but according to certain embodiments such that a flow of fluids, so liquids and / or gases through the solid anion exchanger possible is.
  • salt bridge space is hereby used with regard to its function to act as a "bridge" between anode arrangement and cathode arrangement and in this case to have cations and anions, which in the present case do not have to form salts, since in the present case at least one ion exchanger is present in the salt bridge space.
  • this term is not common, the space is referred to as salt bridge space according to the invention, even if there is no salt in the classical sense.
  • the dimensions of the salt bridge space are also not particularly limited, and it may for example be formed as a space or gap, for example, between the first ion exchange membrane and the first separator, which are arranged, for example, parallel zueinan of.
  • the salt bridge space does not necessarily have to be in contact with the first separator, which adjoins the anode compartment, ie more than three chambers may be present in an electrolysis cell according to the invention.
  • the term "interposed between the first ion exchange membrane and the first separator" means that the salt bridge space may be located anywhere between the first ion exchange membrane and the first separator, in so far as it comprises a solid anion exchanger which at least partially communicates with the first
  • the salt bridge space adjoins the first ion exchange membrane, which does not exclude, however, that a second separator or further separators and / or further cell spaces are present in addition to the first separator
  • the electrolysis cell according to the invention can be constructed, for example, as a multi-chamber cell, eg a three-chamber cell, as described in US 2017037522 A1, DE102017208610.6, and DE102017211930.6, and to which reference is made with respect to such cells is taken.
  • the cathode compartment, the anode compartment and salt bridge compartment are not particularly limited in the electrolytic cell according to the invention in terms of shape, material, dimensions, etc., in so far as they can accommodate the cathode, the anode and the first Ionenaustau shear membrane and the first separator.
  • the three spaces are formed in the electrolysis cell according to the invention, in which case they can be correspondingly separated, for example, by the first ion exchange membrane and the first separator, for example with the first separator between the salt bridge space and the anode space.
  • corresponding supply and discharge devices for starting materials and products for example in the form of liquid, gas, solution, suspension, etc.
  • the individual rooms can be flowed through in parallel streams or in countercurrent.
  • the individual rooms can be flowed through in parallel streams or in countercurrent.
  • in an electrolysis of CO2 - which may still contain CO, so for example, at least 20 vol.% CO2 - this solution to the cathode in solu tion, as gas, etc. are supplied - for example, in countercurrent to an electrolyte flow in the salt bridge space at a three-chamber construction.
  • the respective supply can be provided both continuously and discontinuously, for example pulsed, etc., for which pumps, valves, etc. may be provided in a fiction, contemporary electrolysis - which will also be discussed below, as well as cooling and / or Heating means to catalyze corresponding desired reactions at the anode and / or cathode can.
  • the materials of the respective rooms or the Elektrolysezel le and / or the other components of the electrolysis system can also be suitably adapted to desired reactions, reactants, products, electrolytes, etc. here.
  • at least one power source per electrolytic cell is included.
  • Also before further device parts, which are in electrolysis cells or electrolysis plants V can be provided in the electrolytic sestrom invention or the electrolytic cell according to the invention.
  • a stack is constructed from these individual cells, which comprises 2 to 1000, preferably 2 to 200 cells, and whose operating voltage is preferably in the range of 3 to 1500 V, particularly preferably 200 to 600 V.
  • a gas formed in the salt bridge which corresponds for example to the educt gas, for example CO 2 , which may also, if necessary, traces of H 2 and / or CO ent hold back to the cathode space, where for in a inventive Electrolysis an ent speaking return device can be provided.
  • the cathode according to the invention is not particularly limited and may be adapted to a desired half-reaction, for example with respect to the reaction products, insofar as it contacts the first ion exchange membrane directly, that is in direct contact with the first ion exchange membrane at at least one location, preferably wherein the cathode substantially surface is in direct contact with the first IonenMSermemb ran.
  • the cathode directly adjoins the first ion exchange membrane.
  • a cathode for the reduction of CO 2 and optionally CO may, for example, a metal such as Cu, Ag, Au, Zn, Pb, Sn,
  • the catalyst can be chosen with depending on the desired product. In the case of the reduction of CO 2 to CO, for example, the catalyst is preferably based on Ag, Au, Zn and / or their compounds such as Ag 2 0, AgO, AU 2 O, AU 2 O 3 , ZnO.
  • catalysts for C0 2 reduction can also be used, those who do not have a high overvoltage to hydrogen, eg reduction catalysts such as Pt, Pd, Ir, Os or carbonyl-forming metals such as Fe, Ni, Co, W, Mo.
  • reduction catalysts such as Pt, Pd, Ir, Os or carbonyl-forming metals such as Fe, Ni, Co, W, Mo.
  • the cathode is the electrode at which the reductive half-reaction takes place. It may be one or more parts and be as a gas diffusion electrode, porous electrode or directly with the AEM in the composite, etc.
  • a suitable ionomer for example egg nes anionic ionomer
  • the first Ionenaustau shear for example, an anion exchange membrane (AEM)
  • AEM anion exchange membrane
  • Gas diffusion electrode or porous bonded cata- sator structure which may be partially pressed according to certain embodiments in the first ion exchange membrane, for example, an AEM;
  • porous, conductive, catalytically inactive structure eg carbon-paper-GDL or carbon-paper-GDL (gas diffusion layer, gas diffusion layer), carbon cloth-GDL or carbon-cloth GDL, and / or poly merstreeter film granular glassy carbon impregnated with the catalyst of the cathode and optionally an ionomer that schermembran the connection to the first Ionenaustau, for example, an AEM, impregnated, wherein the electrode then mechanically to the first ion exchange membrane, such as an AEM, pressed or before can be pressed with the first ion exchange membrane, for example an AEM, to form a composite; Particulate catalyst, which by means of a suitable ionomer on a suitable carrier, for example a porous conductive support, is applied and, according to certain embodiments, can abut the first ion exchange membrane, for example an AEM;
  • the first ion exchange membrane for example, an AEM
  • the first ion exchange membrane for example, an AEM
  • this structure then, for example, as a so-called CCM (catalyst-Caoted membrane, catalyst-coated membrane ) can then be pressed onto a conductive, porous electrode, wherein a catalytic activity of this electrode is basically not required and, for example, carbon-based GDI / s or lattices, for example made of titanium, can be used, wherein it is not excluded that this electrode ionomers contains and / or contains the active catalyst or be it in large parts be;
  • CCM catalyst-Caoted membrane, catalyst-coated membrane
  • unfastened sheet e.g. a mesh or expanded metal, for example, consisting of or comprising a catalyst or coated with the sem and according to certain embodiments forms on the first ion exchange membrane, for example, an AEM, is applied;
  • non-ionic gas diffusion electrode which has been subsequently impregnated with a suitable ionomer, for example an anionic conductive ionomer, and according to certain embodiments is applied to the first ion exchange membrane, for example an AEM, or is attached thereto, e.g. via an ionomer.
  • a suitable ionomer for example an anionic conductive ionomer
  • the corresponding cathodes may in this case also contain materials customary in cathodes, such as binders, ionomers, for example anionic ionomers, fillers, hydrophilic additives, etc., which are not particularly limited.
  • the cathode may comprise at least one ionomer, for example an anionic or ion transporting ionomer (e.g., anion exchange resin, anion transport resin), e.g. various functional groups for ion exchange, which may be the same or different, for example, tertiary amine groups, alkylammonium groups and / or phosphonium groups), e.g. conductive, support material (e.g., a metal such as titanium), and / or at least one non-metal such as carbon, Si, boron nitride (BN), boron
  • conductive oxide such as indium tin oxide (ITO), aluminum zinc oxide (AZO) or fluorinated tin oxide (FTO) - for example, as used to prepare photoelectrodes, and / or at least one polymer based on Polyacetylene, polyethoxythiophene, polyaniline or polypyrrole, such as in polymer-based electrodes; non-conductive supports such as polymer networks are possible, for example, with sufficient conductivity of the catalyst layer), binders (eg hydrophilic and / or hydrophobic polymers, eg organic binders, for example selected from PTFE (polytetrafluoroethylene), PVDF (Polyvinyliendifluorid), PFA (perfluoroalkoxy polymers), FEP (fluorinated ethylene-propylene copolymers), PFSA (perfluoro sulfonic acid polymers), and mixtures thereof, in particular PTFE), conductive oxide such as indium tin oxide (ITO),
  • the cathode in particular in the form of a gas diffusion electrode, e.g. bonded to the first ion exchange membrane, or contained in the form of a CCM, according to certain embodiments, contains ionically conductive components, in particular an anionic conductive component.
  • cathode shapes are also possible, for example cathode constructions as described in US 20160251755 A1 and US 9481939.
  • the anode according to the invention is not particularly limited and may be adapted to a desired half-reaction, for example, with respect to the reaction products.
  • the anode which is electrically verbun with the cathode by means of a power source for the provision of the voltage for the electrolysis, takes place in the anode compartment, the oxidation of a substance.
  • the material of the anode is not particularly limited and depends primarily on the desired reaction. Exemplary anode materials include platinum alloys, palladium and glassy carbon, iron, nickel, etc.
  • anode materials are also conductive oxides such as doped TiO 2, indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped Zinc oxide (AZO), iridium oxide, etc. These catalytically active compounds can only be superficially applied in thin film technology, for example, on a titanium and / or carbon support.
  • the anode catalyst is not particularly limited. As cata- capacitor for 0 2 - or Cl 2 ⁇ generation, for example, IrO x (1.5 ⁇ x ⁇ 2) or RuCg are used.
  • These may also be present as mixed oxide with other metals, eg TiCg, and / or be supported on a conductive material such as C (in the form of carbon black, activated carbon, graphite, etc.).
  • a conductive material such as C (in the form of carbon black, activated carbon, graphite, etc.).
  • catalysts based on Fe-Ni or Co-Ni for O 2 generation for this purpose, for example, the un described construction with bipolar membrane or bipolar membrane is suitable.
  • the anode is the electrode at which the oxidative half reaction takes place. It can also be designed as a gas diffusion electrode, porous electrode or solid electrode or solid electrode, etc.
  • a suitable ionomer for example egg nes cationic ionomer
  • the first separator for example a cation exchange membrane (CEM) or a diaphragm, e.g. can be glued ion-conducting and / or me chanic;
  • CEM cation exchange membrane
  • diaphragm e.g. can be glued ion-conducting and / or me chanic;
  • Gas diffusion electrode or porous bonded cata- capacitor structure which may be partially pressed into the first separator, for example a CEM or a diaphragm, according to certain embodiments;
  • particulate catalyst applied by means of a suitable ionomer to a suitable support for example a porous conductive support, and according to certain embodiments may abut the first separator, for example a CEM or a slide;
  • the gate in the first Separa for example, a CEM or a diaphragm, is pressed and, for example, lei tend connected accordingly;
  • unfastened sheet e.g. a mesh or expanded metal, for example, consisting of or comprising a catalyst or coated with the sem and according to certain embodiments forms on the first separator, for example a CEM or a diaphragm, is applied;
  • solid electrode in which case there may also be a gap between the first separator, for example a CEM or a diaphragm, and the anode;
  • porous, conductive carrier which is impregnated with a suitable catalyst and optionally an ionomer and according to certain embodiments on the first Se parator, for example a CEM or a Dia phragma, is applied;
  • non-ionic gas diffusion electrode which has subsequently been impregnated with a suitable ionomer, for example a cation-conductive ionomer, and, according to certain embodiments, is applied to the first separator, for example a CEM or a diaphragm;
  • a suitable ionomer for example a cation-conductive ionomer
  • the electrode e.g. contains an anodically stable anionic conductive material and is located directly on the anionic conductive layer of a bipolar membrane.
  • the corresponding anodes can also contain materials customary in anodes such as binders, ionomers, for example cation-conducting ionomers, for example containing sulfonic acid and / or phosphonic acid groups, fillers, hydrophilic additives, etc., which are not particularly limited for example, also described above with respect to the cathode.
  • the cathode and / or the anode is a gas diffusion electrode, a porous bound catalyst structure, as a particulate catalyst on a support, as a coating of a particulate catalyst on the first and / or second ion exchange membrane, as a porous conductive support into which a catalyst is impregnated, and / or forms out as a non-closed sheet.
  • the cathode as a gas diffusion electrode, as a porous bound catalyst structure, as a particulate catalyst on a support, as a coating of a particulate catalyst on the first and / or second ion exchange membrane, as a porous leitfä Higer carrier in which a catalyst is impregnated
  • the anode is a gas diffusion electrode, a porous bonded catalyst structure, a particulate catalyst on a support, as a coating of a particulate catalyst on the first and / or second ion exchange membrane, as a porous conductive support into which a catalyst is impregnated. and / or formed as a non-closed sheet, which (r / s) holds a cation exchange material ent and / or coupled to a bipolar membrane and / or ge is bound.
  • the anode and / or the cathode are contacted with a conductive structure on the side facing away from the salt bridge space.
  • the conductive structure is not particularly limited here.
  • the anode and / or the cathode are therefore contacted in accordance with certain embodiments of the salt bridge opposite side by leitfähi ge structures. These are not particularly limited. These may be, for example, coal flows, Metal foams, metal knits, expanded metals, Grafitstruktu ren or metal structures act.
  • the electrodes mentioned above by way of example can be combined with one another as desired.
  • electrolytes may also be present in the anode space and / or cathodes, which are also referred to as anolyte or catholyte, but it is not excluded according to the invention that no electrolytes are present in the two spaces and correspondingly, for example, only Ga se for reaction in These are supplied, for example, only CO 2 , if necessary, as a mixture with, for example, CO and / or H 2 O, which may also be liquid, for example as an aerosol, but before given to gaseous H 2 O to the cathode and / or water or HCl to the anode.
  • an anolyte is present which may differ from or correspond to an electrolyte of the salt bridge space, for example with respect to contained solvents, acids, etc.
  • a catholyte is in this case the electrolyte flow to the cathode or at the cathode and is used according to certain embodiments forms the supply of the cathode with substrate or reactant.
  • the catholyte can be used, for example, as a solution of the substrate (CO 2) in a liquid carrier phase (eg water) and / or as a mixture of the substrate with other gases (eg CO + CO 2, water vapor + CO 2, N 2 and / or also) certain proportions of O 2 , SO 2 , SO 3, etc.) are present. Also can be present by a recirculation intimidge led gases such as CO and / or H 2 .
  • the substrate can also be in the form of a pure phase, for example CO 2 . If uncharged liquid products are formed during the reaction, they can be washed out by the catholyte and can then optionally be separated off as required.
  • An anolyte is an electrolyte stream around the anode or at the anode and, according to certain embodiments, serves to supply the anode with substrate or starting material and, if appropriate, from the anode products.
  • the anolyte is an aqueous electrolyte, wherein the corresponding anolyte may optionally be added to the anolyte, which are reacted at the anode.
  • the educt addition is not particularly limited here.
  • the educt addition in the supply to the cathode space is not limited.
  • CO 2 may be added to water outside the cathode compartment, or may also be added through a gas diffusion electrode, or may be supplied only as a gas to the cathode compartment.
  • the anode compartment depending on the reactant used, for example water, HCl, NaCl, KCl, etc., and the desired product.
  • the first ion exchange membrane which contains an anion exchanger and / or anion transporter or an anion transport material and which adjoins the cathode compartment is not particularly limited in the present invention. It separates in the electrolytic cell according to the invention as well as in the inventions to the invention process, the cathode of the salt bridge space, so that from the direction of the cathode space in the direction of the electrolyte, the order of cathode / first ion exchange membrane / salt bridge space results.
  • the first ion exchange membrane is an anion exchange membrane and / or anion transporter membrane.
  • the first ion exchange membrane may have a hydrophobic layer, for example on the cathode side for better gas contacting.
  • the anion exchange membrane and / or Anionentrans portermembran also acts as cation (albeit in traces, for example), in particular proton, blocker.
  • an anion exchanger and / or anion transporter with tightly bound Ka tions can represent a blockade for mobile cations by Coulombabcircung what a Salzausschei tion, in particular within the cathode, in addition can counteract entge.
  • MEA membrane electrode assembly
  • a concentration gradient can not be easily degraded on the electrode side, since a catalyst-based cathode, which is designed as set out above, e.g. ei ne gas diffusion electrode or a CCM, optionally only has a very poor Anionenleitein, depending on the anion and a selected electrolyte.
  • a catalyst-based cathode which is designed as set out above, e.g. ei ne gas diffusion electrode or a CCM, optionally only has a very poor Anionenleitposition, depending on the anion and a selected electrolyte.
  • ion transport agents in particular anion transport resins, can be used as binder material or additive in the electrode itself
  • anion exchanger layer which rests against the cathode in order, for example, to quickly dissipate or partly buffer off OH ions which are formed, so that the action with CO 2 and the associated formation of hydrogencarbonates and / or carbonates can be reduced or the anion transport resins HCCg or CCg 2- direct self.
  • an anion transport can take place by Anionenaus exchanger.
  • an integrated anion exchanger again provides a blockage for cations, e.g. Metallkationpuren, what a Salzaus divorce and contamination of the electrode can additionally counteract entge.
  • cations e.g. Metallkationpuren
  • protons for example, the formation of hydrogen can be suppressed.
  • the first ion exchange membrane may thus contain, for example, an anion exchanger and / or anion transporter in the form of an anion exchanger and / or transporter layer, in which case further layers such as hydrophobicizing
  • the first ion exchange membrane is an anion exchange membrane and / or anion transporter membrane, ie, for example, an ion-conducting membrane (or also a membrane having an anion exchange layer and / or anion transport layer) with positively charged functionalizations, which is not particularly limited , A preferred charge transport takes place in the Anionenaus exchanger layer and / or Anionentransporter für or an anion exchange membrane and / or Anionentransportermembran by anions.
  • the first ion exchange membrane and / or an anion exchanger layer and / or anion transport layer or an anion exchange membrane and / or anion transport membrane serves to provide an anion transport along fixed fixed positive charges.
  • an electrolyte for example proton-containing electrolyte
  • the ion exchanger contained in the membrane may, according to certain embodiments, be in particular in operation in the carbonate / hydrogen carbonate form and thereby suppress the passage of protons through the membrane to the cathode.
  • a suitable first ion exchange membrane for example anion exchange membrane and / or anion transporter membrane, exhibits, according to certain embodiments, a good wettability by water and / or acids, in particular aqueous acids, a high ionic conductivity, and / or a tolerance of the functional groups contained therein to high pH values. Values, in particular shows no Hoffmann elimination.
  • An exemplary AEM according to the present invention is the A201-CE membrane marketed by Tokuyama, the "Sustainion" marketed by Dioxide Materials, or an anion exchange membrane sold by Fumatech, such as Fumase FAS-PET or Fumasep FAD-PET.
  • the first separator is not particularly limited.
  • the first separator for example according to certain embodiments, seen from the anode side adjacent to the salt bridge space, selected from an ion exchange membrane containing a cation exchanger, a bipolar membrane, wherein in the bi-polar membrane preferably the cation conductive layer toward the cathode is oriented and the anions conductive layer towards the anode, and a diaphragm.
  • the first separator is a cation exchange membrane, a bipolar membrane or a diaphragm.
  • a suitable first separator for example a cation exchange membrane or a bipolar membrane, contains, for example, a cation exchanger which can be in contact with the salt bridge space. It may, for example, contain a cation exchanger in the form of a cation exchanger layer, in which case further layers, such as hydrophobicizing layers, may be contained. It may also be designed as a bipolar membrane or as a cation exchange membrane (CEM).
  • the cation exchange membrane or cation exchange layer is, for example, an ion-conductive membrane or ion-conductive layer with negatively charged functionalities. Exemplary charge transport into the salt bridge space takes place in such a first separator by means of cations.
  • Nafion® membranes are suitable as CEM, or even the Fumatech-driven Fumapem-F membranes, the Asahi Kasei-marketed Aciplex, or the Flemion membranes marketed by AGC.
  • the first separator prevents the passage of anions, in particular HCO3-, into the anode compartment.
  • the first separator may be formed as a diaphragm, whereby the cell less complex and cheaper can be designed.
  • the diaphragm essentially separates the anode space and the salt bridge space, for example more than 70%, 80% or 90%, based on the interface between anode space and salt bridge space, or separates the anode space and the salt bridge space, that is to say 100%, based on the boundary surface between anode space and salt bridge space.
  • Particularly preferred are embodiments which effect gas separation, e.g. the CO2 in the salt bridge space and the O2 in the anode space.
  • the diaphragm is not particularly limited in this case and may be based, for example, on a ceramic (e.g., ZrO 2 or Zr 3 (PO 4) 3) and / or a swellable functionalized polymer, e.g. PTFE, be.
  • a ceramic e.g., ZrO 2 or Zr 3 (PO 4)
  • a swellable functionalized polymer e.g. PTFE
  • binders e.g., hydrophilic and / or hydrophobic polymers, e.g., organic binders, e.g., selected from PTFE (polytetrafluoroethylene), PVDF
  • conductive fillers eg carbon
  • non-conductive fillers eg glass
  • hydrophilic additives eg AI2O3, MgCg, hydrophilic materials like
  • Polysulfones e.g. Polyphenylsulfones (PPSU), polyimides,
  • Polybenzoxazoles or polyether ketones or in general Elekt rolyten electrochemically stable polymers may be present.
  • the diaphragm is porous and / or hydrophilic. Since it is not ion-conductive itself, it should preferably be able to swell in an electrolyte, such as an acid. Furthermore, it is a physical barrier to gases and can not be penetrated by gas bubbles. For example, it is a porous polymer structure wherein the base polymer is hydrophilic (eg PPSU). In contrast to the CEM or bipolar membrane, the polymer does not contain charged functionalities. Furthermore, the diaphragm may further preferably comprise hydrophilic structuring components such as metal oxides (eg, ZrO 2 and / or other materials such as particles over the top of which flies) or ceramics as set forth above.
  • hydrophilic structuring components such as metal oxides (eg, ZrO 2 and / or other materials such as particles over the top of which flies) or ceramics as set forth above.
  • a suitable first separator for example, a cation exchange membrane, a bipolar membrane and / or a diaphragma, exhibits, according to certain embodiments, good wettability by water and / or acids, high ionic conductivity, stability to reactive species generated at the anode can be (for example ge give perfluorinated polymers), and / or stability in the required pH regimes, for example, to an acid in the salt bridge space.
  • the first ion exchange membrane and / or the first separator are hydrophobic, in particular so that they form a CCM with the electrodes, at least on the side facing the electrodes, so that the starting materials of the electrodes are present in gaseous form.
  • the anode and / or cathode are at least partially hydrophilic.
  • the first ion exchange membrane and / or the first separator are wettable with water. In order to ensure a good ionic conductivity of ionomers, it is preferable to swell with water. The experiment has shown that poorly wettable membranes or separators can lead to a significant deterioration of the ionic bonding of the electrodes.
  • the anode and / or cathode also have sufficient hydrophilicity. Possibly. This can be adjusted by hydrophilic additives such as Ti0 2 , A1 2 0 3 , or other electrochemically inert metal oxides, etc.
  • At least one of the following first separators is used:
  • a diaphragm is preferably used when the salt bridge (the electrolyte in the salt bridge space) and the anolyte ne identical, preferably inert, acid or consist of this, in which case the diaphragm serves to keep gases separated so that carbon dioxide is not in the anode space crossing, and / or if at the anode 0 2 is produ ed, in particular to save costs.
  • a cation exchange membrane or a membrane with a cation exchange layer are used in particular when an electrolyte in the salt bridge space - also referred to in the context of the invention as "salt bridge", and the anolyte are not identical, and / or in particular when the anolyte HCl, HBr and / or HI contains, and / or if a Chlorproduk tion at the anode takes place.
  • the cation exchange membrane the passage of anions from the anolyte into the salt bridge prevented and in contrast to the diaphragm has no open Po rosity, the anode can be designed freely. In principle, in such an embodiment, it is preferable for the anode reaction to release no mobile cations except protons that can pass into the salt bridge through the CEM.
  • the anode compartment can be designed independently of the salt bridge and the cathode compartment, which allows a multiplicity of anode reactions with desired products, and in particular when using bases, cheaper anodes or anode catalysts, for example nickel, can also be used or iron based anode catalysts for oxygen evolution.
  • a bipolar membrane may, for example, be designed as a sandwich of a CEM and an AEM. In this case, but usually not two superimposed membranes before present, but it is a membrane with at least two layers. These membranes are almost impassable for both anions and cations.
  • the conductivity of a bipolar membrane is therefore not based on the ability to transport ions. Instead, ion transport usually occurs by acid-base dissociation of water in the middle of the membrane. As a result, two opposite gela dene charge carriers are generated, which are ported by the E-field abtrans. Since the conductivity of the bipolar membrane is based on the separation of charges in the membrane, however, is usually expected with a higher voltage drop.
  • a bipolar membrane as the first separator membrane
  • bases e.g. a hydroxide base
  • the anode contacts the first separator, as already described above by way of example.
  • a good connection to the salt bridge space is possible, please include.
  • no charge transport through the anolyte is necessary in this case and the charge transport path is shortened.
  • electrical shading effects by supporting structures between the anode and the first separator can be bypassed so.
  • the solid anion exchanger which is at least partially in contact with the first ion exchange membrane and is included in the salt bridge space, according to the invention is not limited FITS, if it is present as a solid - so not in solution, can exchange anions, and at least partially with the first ion exchange membrane in Contact is.
  • the solid anion exchanger is hydrophilic.
  • the solid anion exchanger at least in the region of the cathode on the opposite side of the first ion exchange membrane, is substantially in contact therewith, that is to say more than 50% of the area of the first ion exchange membrane, preferably more than 60 %, more preferably more than 70%, in particular more than 80%, are in contact with the solid anion exchanger - that is, touching it, based on the area of the first ion exchange membrane which is in contact with the cathode.
  • the solid anion exchanger is not in full contact with the first ion exchange membrane, especially not in the region where the cathode on the opposite side of the first ion exchange membrane contacts it to provide a fluid transfer between the first anion exchange membrane and the solid ion exchange membrane To ensure anion exchangers.
  • the further mechanical design of the solid Anionenaus exchanger which can also be understood as a filling medium, is not particularly limited, and it may be formed, for example, as a bed of solid anion exchange particles, which are not particularly limited, as a porous structure, for example, spongy, and / or as, for example, regular, porous self-supporting structure.
  • the particles preferably have a particle size between 5 ⁇ m and 2 mm, more preferably between 100 ⁇ m and 1 mm, it being possible to determine the particle size for example with sieve analysis.
  • the particles are adapted to the size of the cell and / or to the corresponding flow regime.
  • the solid anion exchanger is present as a bed and / or a porous structure.
  • the solid Anionenaus exchanger optionally with other solid constituents, such as neutral particles or cation exchangers, in Salz viten space forms a filling.
  • a regularly porous self-supporting structure as it can be, for example, by casting around polymer beads with a solution of the anion exchange material of the solid Anionenaus exchanger and subsequent dissolution of the template balls he can be.
  • the structure should be at least partially open or open in order to ensure an electrolyte and gas flow can.
  • porous carrier beats (latex beads) can also be impregnated with an anion exchange ionomer and thus function as anion exchange particles.
  • the bonding of a particle bed of any, for example neutral and / or uncharged, for example polymeric, particles with an anion exchange ionomer is in accordance with certain Embodiments preferred.
  • the advantage of this method is a higher number of exchanger groups available for the transport of anions.
  • the solid anion exchanger serves as an open extension of the first ion exchange membrane, for example an AEM, into the volume of the salt bridge space (eg referred to as the gap volume if the salt bridge space is formed as a gap).
  • the surface of anion-conducting constituents of the electrolysis cell for example of bicarbonate and / or carbonate-conducting constituents of the electrolytic cell in a C0 2 -electrolyte, can be greatly increased.
  • the solid anion exchanger has an intrinsic ionic conductivity, which can produce an additional conduction path through the salt bridge space by only solid electrolytes.
  • the first separator for example, not only HCCg and / or CO3 2 but also or only one anion of the electrolyte used in the salt bridge space, for example a used acid, can serve as a mobile charge carrier in the solid ion exchanger.
  • the solid anion exchanger should preferably be selected such that it also has a good SCY 2- conductance in addition to good HCCG and / or C0 3. 2
  • the material of the solid anion exchanger can be adapted not only to an anion such as HCCy and / or CCy 2 , which is cathodically generated, but also to further anions, for example in the salt bridge space.
  • the material of the solid anion exchanger is not limited insofar as it is adapted to the first ion exchange membrane and / or an electrolyte in the salt bridge space except that it is capable of anion exchange and / or anion transport.
  • the solid anion exchanger may comprise an anion exchanger resin in which cations, preferably alkali and / or alkaline earth metal cations, eg by complex formation, and / or ammonium ions and / or derivatized ammonium ions such as quaternary ammonium ions, more preferably alkali metal cations and / or ammonium ions and / or derivatized ammonium ions such as quaternary ammonium ions are immobilized.
  • phosphonium preferably alkali and / or alkaline earth metal cations, eg by complex formation, and / or ammonium ions and / or derivatized ammonium ions such as quaternary ammonium ions,
  • the solid anion exchanger in the salt bridge space comprises cations immobilized in a polymeric backbone, which cations can exchange for example hydrogen carbonate ions and / or carbonate ions, these hydrogen carbonate ions and / or carbonate ions preferably being transportable through the solid anion exchanger to provide suitable conductivity in the salt bridge space.
  • Anion exchangers are usually in acidic (eg in the HSO 4 -form, where they can also be present as solid acids), neutral (eg as TFO or Cl salt) or basic form (eg HC0 3 form weakly basic, OH form strongly basic) in solid form.
  • acidic eg in the HSO 4 -form, where they can also be present as solid acids
  • neutral eg as TFO or Cl salt
  • basic form eg HC0 3 form weakly basic, OH form strongly basic
  • various such anion exchangers may be present side by side in a cell according to the invention, where basic anion exchangers are preferably used in the vicinity and / or on the first ion exchange membrane.
  • the solid anion exchanger is basic, preferably strongly basic.
  • the immobilized cations of the anion exchange exchanger are such that an ion pair formed by them is always completely dissociated, which can be controlled, for example, by the pH.
  • the solid anion exchanger Hydrogencarbonate, carbonate and / or OH ions and / or Anio NEN of the electrolyte used in the salt bridge space electrolyte, such as an acid, as counterions. This can improve the transport of bicarbonate and / or carbonate from the first ion exchange membrane by means of ion hopping (as opposed to "tunneling" as in the Grotthus mechanism).
  • the solid anion exchanger is hydrophilic. As a result, it is easier to wet with an aqueous medium, so that an aqueous medium, such as an aqueous acid, can be used in the salt bridge space.
  • an aqueous medium such as an aqueous acid
  • the water can also serve as an additional starting material in the reduction of carbon dioxide, as stated above, and allow a good conductivity.
  • the first anion exchanger and / or a Fül treatment comprising the solid anion exchanger, optionally with wide ren solid components, such as neutral particles or Kat ion exchangers, in the salt bridge space also for supporting separators and / or membranes, for example, the first Ionenaustau shear membrane and the first separator, against each other. Since the filling has its own ion conductivity, the shape of the support does not lead to the isolation of electrode rich. When assembling a cell stack or cell stack, the bed can also be used for power transmission (adhesion) through the entire stack or total stack.
  • the filling contains at least in the area of the cathode / AEM a solid, e.g. strongly basic, anion exchangers.
  • the filling may also be made entirely of a solid, e.g. strong basic, anion exchangers best hen.
  • Both components can also be constructed, for example, on the same polymer base, although, for example, the chain length and / or the degree of crosslinking may differ.
  • the salt bridge space comprises only one solid anion exchanger
  • the first separator is shown to be in contact with the anode.
  • the separator may also be present separately from the anode, so that an anode space can also form, for example, between the separator and the anode and, if appropriate, the anode also on an opposite side of such an anode space Space for the supply of substrate, eg of a gas.
  • the solid anion exchanger 4 for example, a strongly basic anion exchanger, arranged in the salt bridge space II, which is located between an anion exchange membrane AEM as the first ion exchange membrane based on egg nes, eg strong base, anion exchange material 1 and a cation exchange membrane CEM as the first separator Base of a, for example, strongly acidic cation exchange material 3 is located.
  • the AEM is followed by the cathode K and the cathode compartment I
  • the CEM is followed by the anode A and the anode compartment III.
  • the fixed Anione 4 are penetrated by fluids such as gases and / or electrolytes. For each of the three rooms I, II, III, a supply and an exhaustion are provided.
  • FIG. 2 An alternative embodiment can be found in Fig. 2, wherein the electrolytic cell largely corresponds to that of Fig. 1, except that the CEM was replaced by a diaphragm D, for example in the form of a hydrophilic gas separator 5.
  • Fig. 3 which also largely corresponds to the embodiment of Fig. 1, wherein the CEM was replaced by a Bipolarmembran BPM set in which a cation exchange layer based on, for. strongly acidic, cation exchange material 3 is directed towards the salt bridge space II, while an anion exchange layer based on a, e.g. strongly basic, AnionenSermaterials 1 is directed towards the anode.
  • the filling may e.g. next to one, e.g. strongly basic and / or weakly basic, anion exchangers, non-ionic ion exchangers, e.g. Poly-alcohols, and / or cation exchangers, e.g., weak and / or strong, include acidic cation exchangers, which are not particularly limited.
  • strongly basic and / or weakly basic, anion exchangers, non-ionic ion exchangers, e.g. Poly-alcohols, and / or cation exchangers e.g., weak and / or strong, include acidic cation exchangers, which are not particularly limited.
  • acidic cation exchangers which are not particularly limited.
  • Fig. 4 shows schematically an exemplary embodiment in which such a filling in the salt bridge space II with a mixed ion exchange material 2 containing e.g. strongly basic, anion exchange material, which may be homogeneously mixed in example, is provided.
  • a mixed ion exchange material 2 containing e.g. strongly basic, anion exchange material, which may be homogeneously mixed in example.
  • the further embodiment of the cell in FIG. 4 corresponds to that of FIG. 1.
  • FIGS. 5 and 6 A comparison of these two cell concepts with, e.g. strongly basic, anion exchange material 4 ( Figure 5) and mixed ion exchange material 2 containing e.g. strongly basic, anion-exchange material (FIG. 6) is also shown in FIGS. 5 and 6 with a generic separator S made of a generic material 6, which may be constructed in one or more layers. The further construction corresponds to that in FIG. 1
  • the solid salt bridge space further comprises non-ionic and / or unfunctionalized particles, nonionic ion exchangers and / or cation exchangers, preferably the non-ionic and / or unfunctionalized particles, nonionic ion exchangers and / or cation exchangers, Furthermore, the non-ion-conducting and / or unfunctionalized particles and / or non-ionic ion exchangers prefer to be in an area adjacent to the first ion exchange membrane in an amount of up to 20% by volume, preferably up to 17% by volume, more preferably up to 14% by volume, still more preferably up to 10% by volume or up to 5% by volume, based on the total amount of solid anion exchanger and uncharged particles, nonionic ion exchanger and / or cation exchanger.
  • the mixture of the solid Anionenaus exchanger with the uncharged particles, the nonionic ion exchanger and / or the cation exchanger is not particularly limited, and may be homogeneous or heterogeneous, eg in the form of layers, etc., be.
  • the uncharged particles, nonionic ion exchangers and / or cation exchangers are not particularly limited.
  • these layers are preferably parallel to the first ion exchange membrane and / or the first separator, wherein the layer adjacent to the first ion exchange membrane contains the uncharged particles, nonionic ion exchangers and / or cation exchangers in an amount of up to 20% by volume, preferably up to 17% by volume, more preferably up to 14% by volume, even more preferably up to 10% by volume or up to 5% by volume, based on the layer, of or only comprises or contains the solid anion exchanger.
  • a layer adjacent to the first separator may, for example, contain the solid anion exchanger in an amount of up to 20% by volume, preferably up to 17% by volume, more preferably up to 14% by volume, even more preferably up to 10% by volume. % or up to 5% by volume, based on the layer, and according to certain embodiments, the balance may be a solid cation exchanger.
  • a layer adjoining the first separator may also comprise or only contain only the solid cation exchange.
  • the salt bridge space further comprises a solid cation exchanger which is at least partially in contact with the first separator.
  • the solid cation exchanger it is preferred in this case for the solid cation exchanger to be in contact at least in the region of the anode on the opposite side of the first separator, ie for example more than 50% of the area of the first separator more than 60%, more preferably more than 70%, in particular more than 80%, that touch this, based on the area of the first separator, which is in contact with the anode.
  • the solid cation exchanger is not in full contact with the first separator, especially not in the region where the anode on the opposite side of the first separator contacts it, to provide fluid transport between the first separator and the solid cation exchanger to be able to guarantee.
  • the first ion exchange membrane e.g. an AEM
  • the first ion exchange membrane e.g. an AEM
  • the composition of the filling must in particular be e.g. not homogeneous along the cathode-anode junction.
  • the filling may also be layered, for example with a, e.g. strong base, solid anion exchanger or a mixture comprising the solid anion exchanger in the region of the cathode and the first ion exchange membrane, e.g. an AEM, and egg nem, e.g. strong-acid, solid cation exchanger or a mixture comprising the solid cation exchanger in the region of the anode and the first separator.
  • a, e.g. strong base, solid anion exchanger or a mixture comprising the solid anion exchanger in the region of the cathode and the first ion exchange membrane e.g. an AEM, and egg nem, e.g. strong-acid, solid cation exchanger or a mixture comprising the solid cation exchanger in the region of the anode and the first separator.
  • first ion exchange shear membrane such as an AEM
  • adjacent material contains one, for example, strongly basic, anion exchanger.
  • two or more layers may be present in such a multilayer construction of the filling, as shown by way of example in FIGS. 7 to 9 for two layers.
  • the cell structure with cathode K, anode A, AEM and separator S and the cathode compartment I and anode compartment III here corresponds to that of FIG. 5, and only the structure of the filling in the salt bridge space II differs.
  • a layer having a, e.g. strongly basic, anion exchange material 4 adjacent to the AEM is a layer having a, e.g. strongly basic, anion exchange material 4, while to the separator S a layer comprising a mixed ion exchange material 2 containing e.g. strongly basic, anion exchange material borders on.
  • the material attached to the AEM is contained by a mixed ion exchange material 2 containing e.g. strongly basic, anion exchange material has been replaced.
  • the filling even if it consists only of the solid anion exchanger, not ge closed, so that they can be traversed by an electrolyte and / or a liquid-gas bubbles mixture, so, for example. Pores or structured open spaces.
  • Another aspect of the present invention relates to an electrolysis system comprising an electrolyte cell according to the invention.
  • the corresponding embodiments of the electrolytic cell as well as other exemplary components of an inventive electrolysis system he have been discussed above and thus are also applicable to the inventive electrolyte sestrom.
  • summarizes an electrolysis plant according to the invention a plurality of electrolysis cells according to the invention, which is not excluded concluded that next to other electrolysis cells are present.
  • the electrolytic system according to the invention further comprises a recycling device, which is connected to a discharge of the salt bridge space and a supply of the cathode space, which is adapted to chuck a starting material of the cathode reaction, which can be formed in the salt bridge space, again in the cathode space ren.
  • An electrolysis cell according to the invention is shown by way of example in Fig. 10, in which case the electrolytic cell with the Ka thodenraum I, the salt bridge space II and the anode space III, the anode A, the separator S, the cathode K and the first ion exchange membrane as AEM, for example, according to the structure can be constructed in Fig. 5 or Fig. 6.
  • CO2 is supplied to the cathode space and CO2 removed from the cathode space, product P and possibly water are removed, the water being separated off.
  • CO2 generated in salt bridge space and possibly CO2 transferred into the salt bridge space can be recycled via a return to the cathode space after the electrolyte j is separated from the salt bridge space, which can also be recycled.
  • the electrolytic system according to the invention further comprises an external device for electrolyte treatment, in particular a device for removing dissolved gases from an acid, with which in particular the anolyte and / or the electrolyte are treated in the salt bridge space, for example gases such as CO2 or O2 too remove, and so allow a return of anolyte and / or the electrolyte in the salt bridge space.
  • an external device for electrolyte treatment in particular a device for removing dissolved gases from an acid, with which in particular the anolyte and / or the electrolyte are treated in the salt bridge space, for example gases such as CO2 or O2 too remove, and so allow a return of anolyte and / or the electrolyte in the salt bridge space.
  • the electrolytic system according to the invention comprises two separate circuits for anolyte and electrolyte in the salt bridge space, which may optionally have separate devices for electrolyte treatment, in particular devices for removing dissolved gases from an acid, or only the circuit for the Elekt rolyt in the salt bridge space a corresponding device has.
  • the present inven tion relates to the use of an electrolysis cell according to the invention or an electrolysis plant according to the invention, which can also include a plurality of electrolysis cells according to the invention, for the electrolysis of CO 2 and / or CO.
  • a method for the electrolysis of CO 2 wherein an electrolysis cell according to the invention or an inven tion proper electrolysis plant is used, wherein CO 2 is reduced at the cathode and at the cathode resulting bicarbonate and / or carbonate through the first Ionenaus exchange membrane to an electrolyte in Salt bridge space wan changed, wherein the hydrogen carbonate and / or carbonate is also transported by the solid anion exchanger in the salt bridge space away from the first ion exchange membrane.
  • the cathode compartment, the cathode, the first ion exchange membrane, the anode compartment, the anode, the separator, the salt bridge compartment and the solid anion exchanger, as well as other components, have already been discussed with regard to the electrolysis cell according to the invention and the electrolysis plant according to the invention.
  • the corresponding features can thus be carried out according to the inventions to the invention process.
  • CCg is electrolyzed with the process according to the invention, although it is not excluded that on the cathode side in addition to CCg another reactant such as CO is present, wel Ches can also be electrolyzed, ie a mixture is present, which includes CO2, and CO, for example.
  • a mixture is present, which includes CO2, and CO, for example.
  • the electrolysis cell according to the invention can also implement pure CO, wherein then, however, no CO2 is released in the salt bridge area.
  • the filling comprising the solid anion exchanger or consisting of the solid An ion exchanger of an electrolyte, that is, a liquid medium, flows through.
  • the electrolyte is not particularly However, according to certain embodiments, it is still aqueous.
  • the salt bridge space comprises an aqueous electrolyte. It may be the anolyte and / or catholyte, if present, ent speak or different from these.
  • the electrolyte of the salt bridge space comprises an acid, preferably a water-soluble or water-miscible acid.
  • the electrolyte contains at least 10 -6 mol / l H + and / or its hydrated variants, preferably at least 10 -4 mol / l, more preferably at least 10 -3 mol / l, even more preferably at least 10 -2 mol /1.
  • the electrolyte of the salt bridge space comprises substantially no mobile cations other than H + and / or its hydrated variants.
  • the electrolyte does not comprise any mobile cation except protons, apart from mobile cations in a quantity of common impurities. The electrolyte serves to discharge the C02 and to keep the filling moist.
  • the at least one acid in the electrolyte in the salt bridge space is not particularly limited, but is preferably a water-soluble and / or water-miscible acid, such as HCl, HBr, HI, H2SO4, H3PO4, HTfO (trifluoromethanesulfonic acid), etc.
  • a water-soluble and / or water-miscible acid such as HCl, HBr, HI, H2SO4, H3PO4, HTfO (trifluoromethanesulfonic acid), etc.
  • improved gas release in the salt bridge space can be achieved by using more layered fillings, as described above, can be achieved. It is also possible, of course, in the salt bridge room
  • the first separator and possibly other separators contained and / or ion exchange membranes, for example, with multiple electro lytzu Adjusten to the salt bridge space or layers of Grein conditions , where, if necessary, laminar flows for creating sol cher electrolyte gradients are possible.
  • the filling comprising the solid anion exchanger or consisting of the solid anion exchanger is preferably ion-conductive in order to improve the charge transport through the electrolyte.
  • the first separator is preferably designed as an ion exchanger membrane comprising a cation exchanger, for example as a cation exchange membrane (CEM), or as a bipolar membrane (BPM).
  • the solid filling in addition to the solid anion exchanger then also contains acidic components, e.g. Cation exchanger.
  • acidic components e.g. Cation exchanger.
  • the electrolyte in the salt bridge space comprises at least one acid, since the diaphragm is not intrinsically ion-conducting.
  • the Elekt electrolyte of the salt bridge space may in this case for example correspond to the anolyte, but also be different.
  • a particularly preferred embodiment of the method according to the invention results from the use of the solid anion exchanger, if appropriate in a mixture with further constituents in the filling of the salt bridge space, in combination with an acidic electrolyte.
  • This can be compared to Prior art, the contact area between the Anione exchanger of the first ion exchange membrane and acidic media are greatly increased.
  • solutions according to the prior art for example in US 2017037522 Al and DE
  • the surface of the first Ionenaustau shear membrane is always the transition to the acidic medium.
  • the water transition is moved according to the invention in the volume of Salzbrue ckenraums and thereby the surface massively magnification ßert.
  • the insulating effect of emerging gas bubbles in C0 2 electrolysis has a less negative effect on the cell voltage.
  • the effect of the anion exchanger / transporter contained in the first ion exchange membrane as a transporter for anions can be continued by filling in the salt bridge space.
  • the anode compartment comprises an anolyte which comprises a liquid and / or dissolved acid, preferably wherein the anolyte and / or the acid in the salt bridge space or the electrolyte in the salt bridge space no mo bile cations except protons and / or deuterons, in particular no metal cations.
  • an acid in the salt bridge space does not comprise mobi len cations except protons and / or deuterons, in particular no metal cations.
  • the anolyte does not encompass mobile cations except protons and / or deuterons, especially no metal cations.
  • Mo bile cations here are cations which are not bound by a chemical bond to a support, and / or in particular an ion mobility of more than
  • H + " especially metal cations, released or he witnesses.
  • Anolyte or reagent may be suitable for halogen generation at the anode.
  • the halogen-hydrogen acids HCl, HBr and / or HI suitable, for example halide salts are not suitable when using a diaphragm as the first separator membrane, but used when using a bi-polar membrane as the first separator membrane can be.
  • SCg in the anolyte for the production of sulfuric acid, or H 2 O for the production of H 2 O 2 , etc. is possible.
  • the cathode space I is separated from the salt bridge space II by a composite of a CO 2 reducing cathode K and an AEM.
  • the cathode compartment I is flowed through by, for example moistened, CO 2 , which is thereby reduced, for example, to CO, C 2 H 4 .
  • the moistened C0 2 stream represents the substrate supply of the cathode. In the sense of a classic three-chamber cell, it represents the catholyte.
  • the salt bridge space II is separated from the anode space III by the first separator S (eg diaphragm, bipolar membrane, cation-conducting membrane) in combination with the anode A, wherein - as stated above, it is also possible for the anodization space III to be direct connects to the first separator.
  • the salt bridge space II is packed with a permeable solid filling which contains a, e.g. contains strongly basic, Anionenaus exchanger, and is flowed through by an electrolyte flow, which may include an acid in addition to water.
  • the first separator can be made freely from, for example, a cation exchange membrane (CEM), a non-intrinsically ion-conducting hydrophilic gas separator (diaphragm) or a bipolar Membrane (BPM), in which preferably the anion-conducting layer is oriented towards the anode, to be selected.
  • CEM cation exchange membrane
  • diaphragm non-intrinsically ion-conducting hydrophilic gas separator
  • BPM bipolar Membrane
  • the electrolyte in the anode compartment III and the liquid electrolyte in the salt bridge compartment II are preferably identical and conductive.
  • the anode compartment III is flowed through by the anolyte, eg aqueous HCl, aqueous H 2 SO 4 , H 2 O, etc., which can supply the anode A with substrate.
  • the electrolyte of the salt bridge space and the anolyte have been selected to be identical, they can also be obtained from a common reservoir, but in particular suitable devices are provided to prevent carryover of dissolved gases (degassing), for example when the electrolyte is returned.
  • the Ano denraum III also be located between the anode A and the first Separa tor S. In such a case, however, the anolyte must be conductive.
  • the cathode space I and the anode space III may also include, for example, electrically conductive, eg not closed, structures that serve to contact the electrodes. If the anode is not at the first separator, the requirement of conductivity can be omitted here.
  • the anolyte contains only salts and thus mobile "non H + " cations, when the first separator is a bipolar membrane.
  • the electrochemical conversion at the anode is not further limited, wherein it preferably leads to the transfer of H + from (Bi polar membrane) or through (diaphragm or CEM) the first separator in the electrolyte of the salt bridge space.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

La présente invention concerne une cellule d'électrolyse présentant une construction à plusieurs chambres, une première membrane échangeuse d'ions, comprenant un échangeur d'anions, étant reliée à une chambre de cathode, une chambre de pont de sel, comprenant un échangeur d'anions solide, se raccordant à cette première membrane échangeuse d'ions ; une installation d'électrolyse présentant une telle cellule d'électrolyse ; ainsi qu'un procédé pour l'électrolyse de CO2 utilisant une telle cellule d'électrolyse ou une telle installation d'électrolyse.
EP18810945.8A 2017-12-21 2018-11-19 Charges d'échangeurs d'anions pouvant être traversées pour une fente d'électrolyte dans l'électrolyse de co2 pour une meilleure répartition spatiale du dégagement gazeux Withdrawn EP3695028A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102017223521.7A DE102017223521A1 (de) 2017-12-21 2017-12-21 Durchströmbare Anionentauscher-Füllungen für Elektrolytspalte in der CO2-Elektrolyse zur besseren räumlichen Verteilung der Gasentwicklung
PCT/EP2018/081741 WO2019120812A1 (fr) 2017-12-21 2018-11-19 Charges d'échangeurs d'anions pouvant être traversées pour une fente d'électrolyte dans l'électrolyse de co2 pour une meilleure répartition spatiale du dégagement gazeux

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EP3695028A1 true EP3695028A1 (fr) 2020-08-19

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WO (1) WO2019120812A1 (fr)

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DE102018202184A1 (de) 2018-02-13 2019-08-14 Siemens Aktiengesellschaft Separatorlose Doppel-GDE-Zelle zur elektrochemischen Umsetzung
DE102018210303A1 (de) 2018-06-25 2020-01-02 Siemens Aktiengesellschaft Elektrochemische Niedertemperatur Reverse-Watergas-Shift Reaktion
CN115956138A (zh) * 2020-06-09 2023-04-11 十二益公司 电解装置输出中高浓度多电子产物或co的系统和方法
US20230010993A1 (en) * 2021-07-12 2023-01-12 Dioxycle Carbon dioxide extraction electrolysis reactor
DE102021214631A1 (de) 2021-12-17 2023-06-22 Siemens Energy Global GmbH & Co. KG Zellkonzept zur Nutzung nicht-ionisch leitfähiger Extraktionsmedien
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US20210180196A1 (en) 2021-06-17
CN111556908A (zh) 2020-08-18
DE102017223521A1 (de) 2019-06-27

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