CN117699738A

CN117699738A - Method for producing hydrogen molecules by energy radiation in combination with ultrasonic vibration

Info

Publication number: CN117699738A
Application number: CN202410021871.5A
Authority: CN
Inventors: 王琮; 霍海滨; 饶文涛; 李文武; 马志力; 孟庆章
Original assignee: Baowu Clean Energy Co ltd; Beijing Guanghe New Energy Technology Co ltd
Current assignee: Baowu Clean Energy Co ltd; Beijing Guanghe New Energy Technology Co ltd
Priority date: 2024-01-05
Filing date: 2024-01-05
Publication date: 2024-03-15

Abstract

The invention relates to a method for generating hydrogen by energy radiation, comprising: contacting a composite catalyst with at least one hydrogen-containing source in the presence of an ultrasonic field and energy irradiating the composite catalyst and the hydrogen-containing source to produce hydrogen molecules, wherein the composite catalyst comprises at least one nano-substrate structure and at least one atomic site comprising one or more chemical elements of Mn, co, fe, al, cu, ni, zn, ti, la.

Description

Method for producing hydrogen molecules by energy radiation in combination with ultrasonic vibration

Technical Field

The invention relates to a method for preparing hydrogen by combining energy radiation with ultrasonic field catalysis, in particular to a composite catalyst and application thereof in preparing hydrogen by combining energy radiation with ultrasonic field catalysis.

Background

In the field of new energy, hydrogen energy has generally been considered as an optimal, pollution-free new century green energy source, since the only product after combustion of hydrogen is water. Hydrogen is the most abundant element in nature and is widely present in water, fossil fuels and various types of carbohydrates. Hydrogen is also a main industrial raw material, and is the most important industrial gas and special gas, and is used as an important raw material for synthesizing ammonia, methanol and hydrochloric acid, as a reducing agent for metallurgy, as a hydrodesulfurizing agent for petroleum refining, and the like.

However, the traditional hydrogen production method needs to consume huge conventional energy, so that the hydrogen energy cost is too high, and the popularization and application of the hydrogen energy are greatly limited. Scientists then want to use inexhaustible and cheap solar energy as a primary energy source in the process of forming hydrogen energy, so that the hydrogen energy development shows wider prospect. Scientists have found that using photocatalytic materials as a "medium" can utilize solar energy to crack water into oxygen and hydrogen necessary for fuel cells, and that technology of producing hydrogen and oxygen from sunlight and water alone is one of the "ideal technologies for humans".

Due to the plasmonic effect, the plasmonic metal catalyst can achieve a great enhancement of localized energy on the nanostructure surface. Therefore, under the condition of mild overall reaction conditions, the catalytic reaction is efficiently promoted, so that the reaction which cannot be achieved at normal temperature and normal pressure is possible. The decomposition of water into hydrogen and oxygen has been achieved in recent years, but so far there is still a need to develop more efficient, more stable and cost effective catalysts.

The concept of monoatomic catalysis has received extensive attention and research since the recent proposal, and with the development of advanced characterization technology, monoatomic catalysts offer the possibility to elucidate the structure-activity relationship of the catalyst from the atomic and molecular level, as well as to connect heterogeneous catalysis and homogeneous catalysis. The single-atom catalyst exhibits activity, selectivity and stability different from those of the conventional nanocatalyst due to its special structure.

Therefore, by combining the advantages of the plasmon effect and the single-atom catalysis, it is possible to develop a hydrogen production catalyst which can meet the commercialization requirements in efficiency, stability and cost.

Acoustic cavitation occurs when liquids are exposed to high intensity ultrasound; cavitation refers to the formation of low-pressure cavities (also known as vacuum bubbles or cavities) in a liquid, which are changed from small to large, briefly oscillate, then implode successively, and instantaneously produce a physical phenomenon of high pressure and high temperature. The strong bursting of bubbles during cavitation can generate instantaneous high temperatures up to 5000 ℃ and instantaneous high pressures up to 1000atm, generating free radicals (containing unpaired electrons, which are very active) causing many chemical (sonogenic) reactions such as oxidation of contaminants, sterilization, polymerization, desulfurization, long chain molecular degradation, etc. At the same time, a flow current, extremely fast microfluidics (speeds up to 500 m/s) and huge shear forces are generated in the cavitation field, facilitating various physical and mechanical effects such as emulsification, particle disruption, cell disruption, homogenization, dispersion, degassing, etc. Chinese patent application CN1899954a discloses a method for preparing hydrogen from methanol under ultrasonic conditions, using copper or copper-containing alloy as catalyst. Chinese patent applications CN102089465A, CN103764875A and CN115287680a both relate to systems for assisting in hydrogen production by electrolysis of water using cavitation methods such as ultrasound. He Yeguang and the like study the influence of power density and reaction temperature under the assistance of ultrasonic waves on the hydrolysis process and hydrogen production characteristics of aluminum particles (He Yeguang and the like, study on the mechanism of hydrogen production by ultrasonic-assisted aluminum-based particle hydrolysis, solar journal, volume 38, 4 th, and 2017, 4 months). In the above documents, a great amount of external energy input is needed by adopting methanol steam reforming or adopting electrochemical mode to produce hydrogen, green energy sources such as solar energy and the like cannot be used, and the produced waste liquid and the like have certain pollution to the environment; the adopted catalyst is also a conventional metal catalyst, and the novel catalysis means such as a plasmon effect cannot be utilized, so that the requirement on the stability of the catalyst is high, the cost is high, the corresponding energy conversion rate is low, and the large-scale production is not easy.

Disclosure of Invention

Based on the technical problems underlying the prior art, the present invention illustrates a novel plasmonic catalytic technique, comprising atomic sites, e.g. monoatomic sites and/or clusters of atoms containing 2-25 atoms, providing a unique method for the preparation of hydrogen by energy radiation in combination with an ultrasonic field for decomposing a hydrogen-containing source, preferably water, in the presence of a cost-effective catalyst.

One aspect of the invention is a method of generating hydrogen by energy radiation comprising:

contacting the composite catalyst with at least one hydrogen-containing source in the presence of an ultrasonic field, and

irradiating the composite catalyst and the hydrogen-containing source with energy to produce hydrogen molecules, wherein

The composite catalyst comprises at least one nano-substrate structure and at least one atomic site comprising one or more chemical elements of Mn, co, fe, al, cu, ni, zn, ti, la, preferably one or more of Co, fe, mn.

In certain embodiments, the atomic site further comprises one or more chemical elements of Ru, rh, ag, au, pt, pd, os, ir, preferably one or both of Ru and Au.

In certain embodiments, the energy radiation is selected from at least one of optical radiation and thermal radiation, preferably optical radiation. In certain embodiments, the thermal radiation is preferably infrared radiation.

In certain embodiments, the ultrasonic field is emitted by an ultrasonic generator and conducted to the reactor via a metal strip.

In certain embodiments, the use of an applied ultrasonic field to assist in the catalytic reaction increases the unit catalyst activity for the production of hydrogen molecules, wherein the ultrasonic vibration frequency is 25-300kHz, preferably 100-250kHz, most preferably 150-250kHz; the power density of the ultrasonic vibration is 80-300W/L, preferably 100-250W/L, more preferably 120-180W/L; the unit catalyst activity for producing hydrogen molecules is increased by 0 to 60% and by 30 to 60% in the preferred ultrasonic frequency and power density ranges.

In certain embodiments, the distance between the nano-substrate structure and the atomic site is less than or equal to 5nm, preferably less than or equal to 1nm, more preferably less than 0.1nm, most preferably both are in intimate contact.

In certain embodiments, the atomic sites are bound to the nano-substrate structure, e.g., physically or chemically.

In certain embodiments, the mass percentage of the atomic sites to the nano-substrate structure is 50% or less, preferably 0.01% to 30%, preferably 0.01% to 5%, more preferably 0.1% to 2%, most preferably 0.1% to 1%.

In certain embodiments, the atomic sites are supported on the surface of the nanosubstrate structure, the internal pores or are distributed in the internal lattice of the nanosubstrate structure, preferably the atomic sites are uniformly distributed, and the atomic sites are spaced apart by 0.2-500nm, preferably 1-50nm, more preferably 1-10nm.

In certain embodiments, the nano-substrate structure is selected from the group consisting of Mn, co, ce, fe, al, ca, cu, ni, ti, zn, si, mo, bi, V, C, N and oxides, nitrides, sulfides, carbides, hydroxides, chlorides, and metal-organic frameworks (MOFs), preferably metal-organic frameworks, tiO ₂ Or Al ₂ O ₃ 。

In certain embodiments, the composite catalyst is a Co and Fe supported or bonded to a metal organic framework (CoFe-MOF) catalyst, a Co and Mn supported or bonded to a metal organic framework (CoMn-MOF) catalyst, a Fe and Co supported or bonded to TiO ₂ (FeCo-TiO) ₂ ) Catalyst or Ru and Co supported on TiO ₂ Of (RuCo-TiO) ₂ ) A catalyst.

In a preferred embodiment, at least one dimension of the nano-substrate structure in length, width, height is from about 1nm to about 1000nm, preferably from about 70nm to about 1000nm, from about 100nm to about 800nm, from about 200nm to about 500nm.

In preferred embodiments, the nano-substrate structures are each independently from about 1nm to about 3000nm in length, width, height, preferably from about 100nm to about 3000nm in length, from about 500nm to about 2500nm, or from about 1000nm to about 2000nm in length, and/or from about 1nm to about 1000nm in width or height, from about 70nm to about 1000nm, from about 100nm to about 800nm, or from about 200nm to about 500nm, or the nano-substrate structures each independently have an aspect ratio of from about 1 to about 20, preferably from about 1 to about 10, or from about 2 to about 8.

In certain embodiments, the shape of the nano-substrate structure is spherical, spines, flakes, needles, grass blades, cylinders, polyhedrons, three-dimensional pyramids, cubes, flakes, hemispheres, irregular three-dimensional shapes, porous structures, or any combination thereof.

In certain embodiments, a plurality of the atomic sites are arranged in a patterned configuration, preferably a multi-layer arrangement, on the nano-substrate structure, or a plurality of the atomic sites are randomly dispersed in and/or on the nano-substrate structure.

In certain embodiments, the energy radiation causes the reaction to proceed at a temperature between about 20 ℃ to about 800 ℃, about 20 ℃ to about 500 ℃, about 50 ℃ to about 300 ℃, about 70 ℃ to about 250 ℃, about 90 ℃ to about 200 ℃, about 100 ℃ to about 180 ℃, about 110 ℃ to about 160 ℃, about 120 ℃ to about 150 ℃, about 130 ℃ to about 150 ℃, etc., and the unit catalyst activity for producing hydrogen is greater than 0.2 μmol g ^-1 h ^-1 Preferably greater than 0.5. Mu. Mol g ^-1 h ^-1 Preferably greater than 3. Mu. Mol g ^-1 h ^-1 Preferably greater than 5. Mu. Mol g ^-1 h ^-1 Greater than 7. Mu. Mol g at the preferred temperature range ^-1 h ^-1 Preferably greater than 10. Mu. Mol g ^-1 h ^-1 Preferably greater than 15. Mu. Mol g ^-1 h ^-1 Preferably greater than 18. Mu. Mol g ^-1 h ^-1 Preferably greater than 20. Mu. Mol g ^-1 h ^-1 Preferably greater than 25. Mu. Mol g ^-1 h ^-1 Preferably greater than 30. Mu. Mol g ^-1 h ^-1 Preferably greater than 40. Mu. Mol g ^-1 h ^-1 。

In certain embodiments, the reaction is initiated using an ultrasonic field in combination with optical or thermal radiation having an optical radiation power of 200-1500W/m and continued using an ultrasonic field in combination with optical or thermal radiation ² Preferably 200-1000W/m ² Most preferably 500-1000W/m ² 。

In certain embodiments, the optical radiation increases the temperature of the composite catalyst and the hydrogen-containing source, preferably the only source of increased temperature.

In certain embodiments, the hydrogen-containing source is selected from the group consisting of water, aldehydes, carboxylic acids, and phenols, and any combination thereof, preferably water.

In some embodiments, when the atomic site contains two or more chemical elements and is a single atom, the two or more elements may be arranged at intervals or randomly.

In certain embodiments, where the atomic sites are clusters, the composition of each cluster may be the same or different, e.g., each cluster may contain a different elemental composition, and/or contain a different number of atoms.

The catalytic reaction mentioned in the text is a multiphase reaction, and the addition of an ultrasonic field and energy radiation are combined, so that the rapid desorption of the product and the better combination of liquid and gaseous reactants and the surface active sites of the catalyst are facilitated, the speed of the catalytic reaction can be accelerated, and the purposes of improving the yield and even changing the selectivity of certain products are achieved.

Drawings

FIG. 1 shows a Transmission Electron Microscope (TEM) image of a CoFe-MOF composite catalyst.

FIG. 2 shows a schematic diagram of the light-combining ultrasonic vibration catalytic reaction system of the present invention.

FIG. 3 shows a thermal bond ultrasonic vibration catalytic reaction architecture diagram of the present invention.

Detailed Description

The present invention demonstrates that, unexpectedly, a hydrogen-containing source, preferably water, can be converted into hydrogen molecules in the presence of a composite catalyst having plasmonic effects with light radiation and/or heat radiation in combination with ultrasonic vibration as energy input.

Before further describing the present invention, certain terms used in the specification, examples, and appended claims are collected in the following sections. The definitions set forth herein should be read and understood by those skilled in the art in light of the remainder of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Definition of the definition

The term "catalyst" as used herein refers to a substance that exhibits an effect of increasing the rate of chemical reaction by decreasing the reaction activation energy. The rate-increasing effect is referred to as "catalysis". The catalyst is not consumed in the catalytic reaction so they can continue further reactions of the catalytic reactants with small amounts.

The term "plasmonic donor" as used herein refers to a conductor whose real part of the dielectric constant is negative. The plasmonic donor may provide a surface plasmon when excited by electromagnetic radiation.

The term "temperature dependence" as used herein refers to a property that can change when the temperature changes a given level. The temperature difference of the changing characteristic may be of any degree, such as 0.1 ℃, 1 ℃, 5 ℃, 10 ℃, 100 ℃, or 1000 ℃.

The term "chemical element" as used herein refers to a chemical substance consisting of atoms in the nucleus having the same number of protons. Specifically, the chemical element is an element recorded in the periodic table of chemical elements. Chemical elements include natural elements and synthetic elements. Chemical elements also include elements that have more than 118 protons in an as yet undiscovered nucleus.

The term "bonded" or "supported" as used herein refers to being physically or chemically bonded or supported in a surface, internal pore or internal lattice, wherein physical means include van der Waals forces, metallic bonds, and other conventional physical bonding means, and chemical means include ionic bonds, covalent bonds, coordination bonds, and other conventional chemical bonding means.

The term "alloy" as used herein refers to a mixture of metals or a mixture of metals and other elements. The alloy is defined by metallic bonding (metallic bonding) properties. The alloy may be a solid solution of a metallic element (single phase) or a mixture of metallic phases (two or more solutions).

The term "activity per unit catalyst" as used herein refers to the number of moles of product produced per unit time per unit mass of active catalyst under certain reaction conditions. Specifically, unit catalyst activity = moles of reaction product/active catalyst mass/reaction time.

The term "intimate contact" as used herein means that there is substantially no gap between the two, e.g., a distance of 1nm or less, 0.1nm or less, or substantially 0nm, between the two, preferably forming a metal bond or a coordination bond.

The term "aldehydes" as used herein refers to saturated hydrocarbon compounds substituted with a-C (=o) H group, e.g. C ₁ -C ₁₅ Aldehydes, preferably C ₁ -C ₈ Aldehydes, more preferably C ₁ -C ₄ Aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde.

As used herein, the term "carboxylic acid" refers to a saturated hydrocarbon compound substituted with a-COOH group, e.g., C ₁ -C ₁₅ Carboxylic acids, preferably C ₁ -C ₈ Carboxylic acids, more preferably C ₁ -C ₄ Carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid.

The term "phenols" as used herein refers to compounds comprising-OH directly attached to an aromatic ring, such as benzene, naphthalene, which is a single, double or triple ring comprising 5 to 25 carbon atoms, preferably 5 to 20 carbon atoms, most preferably 5 to 15 carbon atoms, and more preferably 6 to 12 carbon atoms.

The term "metal-organic framework (MOF)" as used herein refers to an organic-inorganic hybrid material having intramolecular pores or a metal-organic framework structure having a periodic network structure formed by self-assembly of an organic ligand and metal ions or clusters. The MOF may contain a transition metal, a rare earth metal, a main group metal such as an alkali metal and an alkaline earth metal, etc. as metal elements, for example, cu, zn, cd, fe, ti, mn, al and Co, preferably Ti, and further contain a non-metal element such as O, N, S, P, halogen (e.g., F, cl, br, I), etc. MOFs can be prepared by methods known in the art such as evaporation of solvents, diffusion, hydrothermal or solvothermal methods, ultrasonic and microwave methods, and the like.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

All numerical designations used herein, such as pH, temperature, time, concentration, content and molecular weight, including ranges, are approximations, with (+) or (-) changes occurring in 0.1 or 1.0 increments as appropriate. It will be understood that all numbers may be preceded by the term "about", although not always explicitly indicated.

As will be understood by those skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be readily identified as sufficiently descriptive, and the same range can be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each of the ranges discussed herein can be readily broken down into a lower third, a middle third, an upper third, and the like.

It will also be understood by those skilled in the art that all language, such as "up to", "at least", "above", "below", and the like, includes the recited numbers and refers to ranges that may be subsequently subdivided into subranges as discussed above.

As used herein, "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

Plasmon composite catalyst

One aspect of the present invention is a plasmonic composite catalyst that generates hydrogen molecules by light radiation and/or thermal radiation in combination with ultrasonic vibration.

Without wishing to be bound by theory, the plasmonic composite catalyst of the invention may enhance absorption of optical and/or thermal radiation near its plasmonic resonance wavelength, interact with the starting materials in the reaction to reduce the activation energy of the reaction, thereby enabling the reaction to be initiated by optical and/or thermal radiation in combination with ultrasonic vibration, and increase the reaction rate and/or alter the selectivity of the reaction products.

The plasmon composite catalyst of the present invention comprises two structures: an atomic site and a nano-substrate structure, wherein the atomic site and the nano-substrate structure are in contact with each other. In a preferred embodiment, the mass percentage of the atomic sites to the nano-substrate structure in the plasmonic composite catalyst is 50% or less, preferably 0.01% to 30%, preferably 0.01% to 5%, more preferably 0.1% to 2%, most preferably 0.1% to 1%.

Atomic site

The term "atomic sites" as used herein refers to individual metal monoatoms and/or clusters of atoms comprising 2 to 25, preferably 2 to 20, metal atoms that are stably bound or supported on the surface of the nano-substrate structure and/or in the internal pores and/or internal lattice, preferably uniformly distributed on the nano-substrate structure, more preferably uniformly distributed on the surface of the nano-substrate structure. The metal monoatoms or atoms in the cluster of atoms are present in a valence state between 0 and the highest valence state in which the metal is typically present, the average valence state of the metal atoms being, for example, 0 to +4, or 0 to +3, or 0 to +2, or 0 to +1, preferably 0. The atomic distance between atoms in the atomic clusters is less than 1nm, preferably 0.1-0.5nm.

The atoms in the atomic sites are physically or chemically bound to the atoms in the nano-substrate structure, such as by van der Waals forces, metal bonds, and other conventional physical binding means, or ionic bonds, covalent bonds, coordination bonds, and other conventional chemical binding means, such as by metal bonds forming an alloy, or by coordination bonds forming a complex.

When the atomic sites are mutually independent metal monoatoms, the interaction between the metal monoatoms and atoms in the nano-substrate structure can prevent the metal monoatoms from agglomerating, so that the metal monoatoms are more stable. In some embodiments, in the single-atom sites of the catalytic metal, all the catalytic metal is present in the form of isolated atoms, i.e., the catalytic metal atoms have a dispersity of 100%, so that the catalytic metal atoms can be utilized to the maximum; preferably, all the catalytic metal atoms are directly fixed on the surface of the nano-substrate structure, and the catalytic metal atoms form 100% of interface atoms, so that the catalytic performance can be optimized by maximally utilizing the interaction between metal and substrate interface.

When the atomic sites are mutually independent metal atom clusters, the metal atom clusters are physically or chemically bound to atoms in the nano-substrate structure. The metal clusters are stably dispersed on and/or in the nano-substrate structure.

When the atomic site is a single atom of a single metal element, in some embodiments, the single metal element acts as both a plasmonic donor and a catalytic property donor, the nano-substrate structure providing physical support; in other embodiments, the single metallic element acts as a plasmonic donor, and the nano-substrate structure provides physical support and acts as a catalytic property donor.

When the atomic sites are metal clusters, in some embodiments, some of the clusters containing a particular element act as plasmonic donors and others of the clusters containing a particular element act as catalytic property donors, the nano-substrate structure providing physical support; in other embodiments, the clusters of atoms act as plasmonic donors, and the nano-substrate structure provides physical support and acts as a catalytic property donor.

In other embodiments, the atomic sites and the nano-substrate structure cooperate to provide physical support as a plasmonic donor and a catalytic property donor.

Nano-substrate structure

The term "nano-substrate structure" as used herein refers to a structure having a size range of nano-scale, i.e., at least one dimension of length, width, height, is from about 1nm to about 1000nm, preferably from about 70nm to about 1000nm, from about 100nm to about 800nm, from about 200nm to about 500nm. The nano-substrate structure can have dimensions exceeding 1000nm, for example, having a length in the micrometer scale range, such as 1 μm to 5 μm. In some cases, tubes and fibers having only two dimensions in the nanometer range are also considered nanobase structures. Materials with nano-base structures may exhibit significantly different size-related properties than those observed in bulk materials.

The nano-substrate structures of the present invention are each independently from about 1nm to about 3000nm long, wide, high. The length is preferably from about 100nm to about 3000nm, more preferably from about 500nm to about 2500nm, and still more preferably from about 1000nm to about 2000nm. The width or height thereof is preferably from about 1nm to about 1000nm, preferably from about 70nm to about 1000nm, more preferably from about 100nm to about 800nm, still more preferably from about 200nm to about 500nm.

The nano-substrate structures of the present invention each independently have an aspect ratio (i.e., ratio of length to width/height) of from about 1 to about 20, preferably from about 1 to about 10, or from about 2 to about 8. The nano-substrate structures of the present invention can also have a relatively low aspect ratio, such as about 1 to about 2.

The nano-substrate structures of the present invention each independently have the following shape: spherical, spined, flake, needle, grass leaf, cylindrical, polyhedral, three-dimensional pyramidal, cubical, flaky, hemispherical, irregular three-dimensional shape, porous structure, or any combination thereof.

The nano-substrate structure is selected from the group consisting of Mn, co, ce, fe, al, ca, cu, ni, ti, zn, si, mo, bi, V, C, N and oxides, nitrides, sulfides, carbides, hydroxides, chlorides, and metal-organic frameworks thereof.

The term "nano-substrate structure" as used herein comprises more than 25 atoms, preferably more than 30 atoms.

The plurality of the nano-substrate structures of the present invention can be arranged in a patterned configuration on a substrate, preferably a multi-layer arrangement, or the plurality of the nano-substrate structures can be randomly dispersed in a medium. For example, the nano-substrate structure may be bound to a matrix. In this case, the nano-base structures are not substantially aggregated with each other, but are arranged or stacked in a regular form. Alternatively, a plurality of nano-substrate structures can be dispersed in a liquid medium, wherein each nano-substrate structure can be freely moved relative to other nano-substrate structures.

For example, the nano-substrate structure may have a spike-like or grass-like geometry. Optionally, the nano-substrate structure is a lamellar geometry having a relatively thin thickness. Preferably, the nano-base structure has a nano-jungle, nano-grass, and/or nano-snow flake configuration. The nano-base structure may have a relatively large aspect ratio, and such a nano-base structure may be constructed in the form of nanospikes, nano-snow flakes, or nanoneedles. The aspect ratio may be from about 1 to about 20, from about 1 to about 10, or from about 2 to about 8. Preferably, the length of the nano-substrate structure may be about 100nm to about 3000nm, about 500nm to about 2500nm, or about 1000nm to about 2000nm; the width or height may be from about 1nm to about 1000nm, from about 70nm to about 1000nm, from about 100nm to about 800nm, or from about 200nm to about 500nm.

The nano-substrate structure may be bonded to a substrate. Thus, the nano-substrate structures do not substantially aggregate together, but are arranged in an orderly fashion. The matrix may be formed of a metal or polymeric material (e.g., polyimide, PTFE, polyester, polyethylene, polypropylene, polystyrene, polyacrylonitrile, etc.).

In other examples, the nano-substrate structure has a shape of sphere, cylinder, polyhedron, three-dimensional cone, cube, platelet, hemisphere, irregular three-dimensional shape, porous structure, or any combination thereof. Such nano-substrate structures are each independently from about 1nm to about 1000nm long, wide, high, about 70nm to about 1000nm, about 100nm to about 800nm, or about 200nm to about 500nm.

In addition, the plasmonic atomic catalyst of the invention can function in various states, such as dispersed, aggregated, or attached/grown on other material surfaces. In a preferred embodiment, the plasmonic atomic catalyst is dispersed in a medium, preferably a reactant of the reaction, such as water.

By energyMethod for generating hydrogen molecules by combining radiation with ultrasonic field

Another aspect of the invention is a method for generating hydrogen molecules by optical and/or thermal radiation in combination with ultrasonic vibration, comprising the steps of:

Contacting a plasmonic composite catalyst with at least one hydrogen containing source; and

light radiation and/or heat radiation in combination with ultrasonic vibration acts on the plasmonic composite catalyst, the hydrogen-containing source, to generate hydrogen molecules.

Under the catalysis of the plasmon composite catalyst, energy radiation, namely optical radiation and/or thermal radiation, is combined with ultrasonic vibration to trigger the reaction of the hydrogen-containing source. The reaction of decomposing a hydrogen-containing source, preferably water, to produce hydrogen molecules is an endothermic reaction. Without wishing to be bound by theory, the plasmonic composite catalyst is capable of converting and transmitting the energy of optical/thermal radiation and ultrasonic vibration, thereby allowing the reaction of the present invention to continue. Within a specific temperature range, increasing the temperature may result in a higher energy conversion for producing hydrogen molecules.

The term "ultrasonic vibration" as used herein refers to the action of high-frequency vibrations generated when ultrasonic waves propagate in a medium. In the reaction of the present invention, the ultrasonic vibration frequency is 25 to 300kHz, preferably 100 to 250kHz, and most preferably 150 to 250kHz; the power density of the ultrasonic vibration is 80 to 300W/L, preferably 100 to 250W/L, more preferably 120 to 180W/L. Without wishing to be bound by theory, in the invention, the energy of ultrasonic vibration induces cavitation effect in the reaction system, and the generated instant high temperature, high pressure and shearing force can promote the dissociation of molecules and the formation of free radicals, which is beneficial to the occurrence of chemical reaction for generating hydrogen molecules.

In certain embodiments of the invention, the ultrasonic vibrations are emitted by an ultrasonic generator and conducted to the reactor via a metal strip. Specifically, the ultrasonic generator is adjusted to the required frequency and power, and the metal strip is directly contacted with the outer surface of the reactor to generate a conduction effect. It should be understood that the manner of application of the ultrasonic field is not limited thereto, as long as ultrasonic vibrations of a desired frequency and power can be transmitted to the reactor.

The photoirradiation and/or heat radiation step is performed at a temperature between about 20 ℃ to about 800 ℃, about 20 ℃ to about 500 ℃, about 50 ℃ to about 300 ℃, about 70 ℃ to about 250 ℃, about 90 ℃ to about 200 ℃, about 100 ℃ to about 180 ℃, about 110 ℃ to about 160 ℃, about 120 ℃ to about 150 ℃, about 130 ℃ to about 150 ℃, and the like. At the above temperature, the unit catalyst activity for producing hydrogen is greater than 0.2. Mu. Mol g ^-1 h ^-1 Preferably greater than 0.5. Mu. Mol g ^-1 h ^-1 Preferably greater than 3. Mu. Mol g ^-1 h ^-1 Preferably greater than 5. Mu. Mol g ^-1 h ^-1 Greater than 7. Mu. Mol g at the preferred temperature range ^-1 h ^-1 Preferably greater than 10. Mu. Mol g ^-1 h ^-1 Preferably greater than 15. Mu. Mol g ^-1 h ^-1 Preferably greater than 18. Mu. Mol g ^-1 h ^-1 Preferably greater than 20. Mu. Mol g ^-1 h ^-1 Preferably greater than 25. Mu. Mol g ^-1 h ^-1 Preferably greater than 30. Mu. Mol g ^-1 h ^-1 Preferably greater than 40. Mu. Mol g ^-1 h ^-1 。

The term "heat" as used herein refers to thermal energy transferred from one system to another as a result of heat exchange. The thermal energy may be transferred from an external heat source to the reaction system or may be carried by one reaction component to the other reaction component. In other words, the reaction components carrying thermal energy prior to reaction are also referred to as internal heat sources. In certain embodiments, the thermal radiation increases the temperature of the plasmonic composite catalyst and the hydrogen-containing source in the reactions of the invention.

In the reaction of the present invention, the optical radiation mimics the wavelength composition and intensity of sunlight, so that it can raise the temperature of the catalyst and reactants being irradiated. When the radiation intensity reaches a certain specific level, the temperature of the plasmon composite catalyst and the hydrogen-containing source is increased by light radiation. Preferably, the optical radiation is the only source of elevated temperature.

In the reaction of the present invention, after the reaction starts, the reaction proceeds under irradiation of light in combination with ultrasonic vibration. The term "light" as used herein refers to electromagnetic waves having wavelengths between about 250nm and about 2000 nm. In other words, light refers to visible lightAnd (3) radiating. Preferably, in the reaction of the present invention, the optical radiation power is lower than the solar radiation power (i.e., solar constant). For example, the optical radiation power is 200-1500W/m ² Preferably 200-1000W/m ² Most preferably 500-1000W/m ² . The optical radiation may be sunlight or light emitted by an artificial light source, the optical radiation having a wavelength between about 250nm and about 2000 nm.

The optical radiation of the invention itself can raise the reaction temperature to the desired temperature without additional heating.

The heat radiation of the invention is similar to light radiation, and is derived from blackbody radiation generated by a high-temperature heating element, and the radiation intensity has specific wavelength distribution according to the Planck law; the heat radiation employed in the present invention has its strongest wavelength in the infrared wavelength region ranging from about 2 μm to 10 μm; the catalytic reaction effect of the plasmon composite catalyst under the action of heat radiation is related to the adopted heat radiation wavelength. Without wishing to be bound by theory, the thermal radiation excitation mode used in the invention is different from the direct thermal conduction adopted by traditional thermal catalysis, but the plasmon catalyst directly absorbs the thermal radiation wave (or optical radiation wave) close to the resonance wavelength, so as to excite the catalytic reaction and promote the catalytic effect. In the present invention, the heat radiation is preferably infrared radiation.

The reaction time varies depending on the size of the reaction, the intensity of the radiation, the temperature and other factors, and the reaction is continued using a well-established apparatus with continuous addition of a hydrogen-containing source. The reaction time may be 0.1 hours or more, preferably 0.1 hours to 1000 hours, preferably 0.1 hours to 500 hours, preferably 0.5 hours to 100 hours, preferably 1 hour to 50 hours, preferably 2 hours to 30 hours, most preferably 4 hours to 20 hours.

The reaction may be carried out at low, normal or high pressure, and an appropriate reaction pressure may be selected according to the size of the reaction, the intensity of radiation, the temperature and other factors, for example, the reaction pressure may be at least 1bar, for example, 1bar to 30bar, preferably 1bar to 20bar, preferably 1bar to 10bar, more preferably 1.5bar to 5bar.

Reaction raw materials

In the reaction of the present invention, the reaction raw material includes a hydrogen-containing source such as water, aldehydes, carboxylic acids and phenols, preferably water such as pure water or hard water, and the water may be in a gaseous state or a liquid state.

Reaction product

The reaction of the present invention is capable of generating hydrogen molecules. Without wishing to be bound by theory, the reaction mechanism of the present invention may include the decomposition and recombination of various reactant feedstock molecules at the atomic sites and nano-substrate structures of the plasmonic composite catalyst.

Examples

Example 1 preparation of composite catalyst

CoFe-MOF (Co and Fe supported or bound to MOF) composite catalyst and CoMn-MOF (Co and Mn supported or bound In MOF) the composite catalyst is prepared by the following method:

4.2mL of isopropyl titanate and 7.06g of terephthalic acid were added to a mixed solution containing 108mL of N, N-dimethylformamide and 12mL of methanol. The mixture was stirred at 25 ℃ for 30min using magnetic force until a clear homogeneous solution was obtained. This solution was transferred to a 200mL stainless steel autoclave, which was placed in an oven and heated to 150℃for 16 hours. After cooling to room temperature, washing with methanol for 3 times, centrifuging, and drying in an oven at 80 ℃ for 16 hours to obtain the MOF substrate for later use. The morphology of the MOF substrate is characterized by SEM and is columnar nano particles with the diameter of 700nm and the height of 200 nm.

In a 250mL beaker, 2g of MOF substrate and 100mL of methanol were added and stirred well using magnetic force. Another 100mL beaker was weighed and 8.8mg of ferric nitrate nonahydrate (Fe (NO) ₃ ) ₃ ·9H ₂ O) and 12mg of cobalt nitrate hexahydrate (Co (NO) ₃ ) ₂ ·6H ₂ O), adding 20mL of methanol, stirring and dissolving. The mixture was poured into the MOF dispersion. After stirring for 1h, washing with methanol, filtering and separating by using a Buchner funnel, and drying in an oven at 80 ℃ for 16 hours, the CoFe-MOF composite catalyst is obtained.

With 8.8mg MnCl ₂ The CoMn-MOF composite catalyst can be obtained by replacing ferric nitrate nonahydrate in the process.

The chemical bonding (coordination bonding) of Co, fe, mn and atoms in the MOF substrate in the obtained composite catalyst is characterized by XPS.

₂ ₂ ₂ FeCo-TiO (Fe and Co supported or bonded to TiO) composite catalyst and RuCo-TiO (Ru and Co supported or bonded) ₂ The catalyst is combined with TiO) composite catalyst is prepared by the following method:

0.2g of titanium dioxide (TiO ₂ Anatase, 5-10nm, hydrophilic) was placed in a 500mL beaker, 200mL deionized water was then added thereto, and 100mL of 1mol/L ammonium carbonate ((NH) was added thereto after 15 minutes of magnetic stirring ₄ ) ₂ CO ₃ ) The solution was stirred for an additional 5min and labeled as solution A. 0.0014g of cobalt nitrate hexahydrate (Co (NO) ₃ ) ₂ ·6H ₂ O) and 0.0015g of ferric nitrate nonahydrate (Fe (NO) ₃ ) ₃ ·9H ₂ O) was dissolved in 100mL deionized water and sonicated for 10min, which was slowly added dropwise to the solution A above. After the formed suspension is aged for 2.5 hours at room temperature, the formed precipitate is centrifugally washed for 3 times by deionized water with the rotating speed of 12500rpm, and then is dried for 12 hours at 60 ℃ in an oven to obtain FeCo-TiO ₂ A composite catalyst.

The mixed solution of cobalt nitrate and ferric nitrate was treated with a solution containing 0.0020g of ruthenium trichloride hydrate (RuCl) ₃ ·xH ₂ O) and 0.0014g of cobalt nitrate hexahydrate (Co (NO) ₃ ) ₂ ·6H ₂ The mixed solution of O) can be replaced by RuCo-TiO ₂ A composite catalyst.

₂ ₃ ₂ ₃ ₂ ₃ ₂ ₃ Ru-AlO (Ru supported or bound to AlO) composite catalyst and Au-AlO (Au supported or bound to AlO) composite The catalyst is prepared by the following steps:

17.6mg of ruthenium trichloride (RuCl) ₃ ) Dissolving in 5mL deionized water, and ultrasonic mixing at room temperature for 60 minutes; then adding 2g of activated alumina, and mixing with ultrasound at 40 ℃ for 60 minutes to obtainCollecting the obtained dry solid, washing with deionized water for five times to obtain Ru-Al ₂ O ₃ A precursor. 20mL of sodium hydroxide pre-conditioned to pH 12.0 was combined with 0.4g of sodium borohydride solid (NaBH ₄ ) Slowly adding the mixed solution into the precursor, stirring uniformly, performing suction filtration, washing the obtained solid with deionized water for three times, and drying under nitrogen atmosphere at 80 ℃ to obtain Ru-Al ₂ O ₃ A composite catalyst. With 3.4mg chloroauric acid (HAuCl) ₄ ) Instead of RuCl in the above process ₃ Thus obtaining Au-Al ₂ O ₃ A composite catalyst.

₂ ₂ The Au-CeO (Au loaded or combined with CeO) composite catalyst is prepared by the following method:

1.73g of cerium nitrate hexahydrate (CeNO) ₃ ·6H ₂ O) and 0.0068g of tetrachloroauric acid (HAuCl) ₄ ·3H ₂ O) is dissolved in 10mL of deionized water, slowly and dropwise added into 70mL of 6mol/L sodium hydroxide (NaOH) solution after complete dissolution, and after continuous stirring for 30min at room temperature, the suspension is transferred into a 100mL stainless steel reaction kettle with polytetrafluoroethylene lining, and the temperature is kept at 120 ℃ for 12h. After the reaction was completed, naturally cooled to room temperature, the precipitate was collected by centrifugation and washed with deionized water until the washing solution ph=7, and then dried in an oven at 60 ℃ for 12 hours. Grinding the dried sample fully, placing the ground sample in a tube furnace, heating to 400 ℃ at 5 ℃/min under the air atmosphere, and keeping the temperature for 2 hours to obtain the catalyst Au-CeO used in the experiment ₂ A composite catalyst.

EXAMPLE 2 photocatalytic Hydrogen generating reaction

The catalyst used was a CoFe-MOF composite catalyst prepared according to example 1, the MOF (metal organic framework) being of a nano-substrate structure, the MOF comprising mainly Ti metal elements, characterized by SEM, the MOF substrate being cylindrical nanoparticles with a diameter of 700nm and a height of 200 nm; the atomic sites comprise Co and Fe, are clusters formed by 2-4 metal atoms and are distributed on the surface of the MOF, the distance between the clusters is 5-20nm, and a transmission electron microscope diagram of the CoFe-MOF catalyst is shown in figure 1. The circles in the figure mark the atomic sites (only partially marked) prepared on the nano-substrate, and it can be seen that the atomic sites are more uniformly distributed on the substrate, and the atomic sites are spaced about 1-10nm apart.

Into a sealable pressure-bearing glass tube of 35mL volume was charged 1g of CoFe-MOF composite catalyst and 6mL of ultrapure water, and 4bar Ar was charged with Ar exhaust though the inside air. The glass tube is horizontally placed on the glass wool, so that the catalyst and water are uniformly spread, and the catalyst and water are vertically irradiated from above by using a halogen lamp with controllable voltage. The incident light intensity was about 1000W/m ² . A thermocouple was attached to the lower half of the glass tube to monitor temperature. The temperature of the glass tube is controlled to be 50+/-10 ℃, and the light is continuously irradiated for 18 hours to perform photocatalysis reaction.

After the photocatalytic reaction, the hydrogen content of the gas in the reaction tube was characterized by Thermal Conductivity Detector (TCD) gas chromatography.

The product analysis was performed by gas chromatography of the product after the photocatalytic reaction using a CoFe-MOF composite catalyst. The hydrogen content was 1024ppm. It was calculated that the unit catalyst activity for hydrogen generation was about 10.5. Mu. Mol g ^-1 h ^-1 . After the above reaction was continuously carried out for 10 cycles (180 hours), the catalytic activity of the catalyst for catalyzing the production of hydrogen was not lowered.

Example 3 photo-coupled ultrasonic vibration catalyzed reaction to Hydrogen Generation

A photo-coupled ultrasonic vibration catalytic reaction was performed in the same manner as in example 2 except that ultrasonic vibration was applied using the same CoFe-MOF composite catalyst as in example 2. The ultrasonic vibration is conducted in a mode of connecting a screen frame on the surface of the reactor, connecting a metal plate type connection and conducting ultrasonic waves, wherein the ultrasonic vibration frequency is 150kHz, and the ultrasonic power density is 150W/L.

The reaction system used in example 3 is shown in FIG. 2. After the reaction, the gas after the reaction was subjected to gas chromatography characterization in the same manner as in example 2. The hydrogen content was 2634ppm. Calculated to be 16.2. Mu. Mol g per unit catalyst activity for hydrogen generation ^-1 h ^-1 。

Example 4 thermocatalytic reaction to Hydrogen production

The catalyst used was the same CoFe-MOF composite catalyst as in example 2.

Into a sealable pressure-bearing glass tube of 35mL volume was charged 1g of CoFe-MOF composite catalyst and 6mL of ultrapure water, and 4bar Ar was charged with Ar exhaust though the inside air. The reaction tube is tightly wound by the heating belt and then is horizontally placed on the glass wool. The temperature of the heating belt is controlled to be 130+/-10 ℃, and the reaction is continuously carried out for 18 hours to carry out the thermocatalytic reaction.

The gas after the reaction was gas chromatographically characterized in the same manner as in example 2. Calculated to have a hydrogen content of 5148ppm, a unit catalyst activity for generating hydrogen of about 25.35. Mu. Mol g ^-1 h ^-1 。

Example 5 thermally bonded ultrasonic vibration-catalyzed reaction to Hydrogen Generation

With the same catalyst as in example 4, a thermally bonded ultrasonic vibration catalytic reaction was performed in the same manner as in example 4, except that ultrasonic vibration was applied. The ultrasonic vibration frequency is 150kHz, and the ultrasonic power density is 150W/L.

The reaction system used in example 5 is shown in FIG. 3. After the reaction, the gas after the reaction was subjected to gas chromatography characterization in the same manner as in example 2. The hydrogen content was 8503ppm. Calculated to be 33.73. Mu. Mol g per unit catalyst activity for hydrogen generation ^-1 h ^-1 。

The results of examples 2 to 5 show that the process of the present invention is capable of directly converting readily available raw materials into hydrogen gas with high efficiency using a cost-effective catalyst under mild overall reaction conditions, for example, under light irradiation power lower than that of solar light, as compared to catalytic reactions without applying ultrasonic vibration; in combination with ultrasonic vibration, the rate of hydrogen generation increases.

Example 6 photo-coupled ultrasonic vibration catalyzed reaction to Hydrogen Generation

In this example, the photo-coupled ultrasonic vibration catalytic reaction was performed in a similar manner to example 3 with the catalyst composition and reaction parameters changed. The reaction conditions and the results are shown in Table 1.

TABLE 1

Example 7 thermally bonded ultrasonic vibration-catalyzed reaction to Hydrogen Generation

In this example, a thermally bonded ultrasonic vibration catalytic reaction was carried out in a similar manner to example 5 with the catalyst composition and reaction parameters changed. The reaction conditions and results are shown in Table 2.

TABLE 2

From the above experimental results, it was found that the activity per catalyst for generating hydrogen gas can be improved by applying ultrasonic vibration of a certain intensity under other reaction conditions.

In summary, the present invention provides a method for improving the reaction yield of a plasmon catalyst for catalytic hydrogen production using energy radiation by applying an ultrasonic field. In the invention, the application of the ultrasonic field can improve the reaction yield under various reaction conditions, has the effect of improving the catalytic activity of various plasmon catalysts, and is beneficial to the commercial development and application of catalytic hydrogen production.

The methods described herein may be performed in any order that is logically possible, except the specific order disclosed.

The representative examples are intended to aid in the description of the invention and are not intended, nor should they be construed, to limit the scope of the invention. Indeed, many modifications of the invention and many other embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art, including the examples and the scientific and patent literature references cited herein. The embodiments contain important additional information, exemplifications and guidance that can be employed by the practice of the invention in its various embodiments and equivalents.

Claims

1. A method of generating hydrogen by energy radiation, comprising:

2. The method of claim 1, wherein

The ultrasonic field is emitted by an ultrasonic generator, preferably conducted to the reactor via a metal strip.

3. The method of claim 1 or 2, wherein

The ultrasonic vibration frequency is 25-300kHz, preferably 100-250kHz, most preferably 150-250kHz, and/or

The power density of the ultrasonic vibration is 80 to 300W/L, preferably 100 to 250W/L, more preferably 120 to 180W/L.

4. A method as claimed in any one of claims 1 to 3, wherein

The atomic site also contains one or more chemical elements of Ru, rh, ag, au, pt, pd, os, ir, preferably one or both of Ru and Au.

5. The method of any one of claims 1 to 4, wherein

The energy radiation is selected from at least one of optical radiation and thermal radiation, preferably optical radiation.

6. The method of claim 5, wherein

The thermal radiation is infrared radiation.

7. The method of any one of claims 1 to 6, wherein

The distance between the nano-substrate structure and the atomic site is less than or equal to 5nm, preferably less than or equal to 1nm, more preferably less than 0.1nm, most preferably both are in intimate contact.

8. The method of any one of claims 1 to 7, wherein

The atomic sites are bound to the nano-substrate structure, for example physically or chemically.

9. The method of any one of claims 1 to 8, wherein

The mass percentage of the atomic sites to the nano-substrate structure is 50% or less, preferably 0.01% to 30%, preferably 0.01% to 5%, more preferably 0.1% to 2%, and most preferably 0.1% to 1%.

10. The method of any one of claims 1 to 9, wherein

The atomic sites are supported on the surface, the internal pore canal, or distributed in the internal lattice of the nano-substrate structure, preferably the atomic sites are uniformly distributed, and

The space between the atomic sites is 0.2-500nm, preferably 1-50nm, more preferably 1-10nm.

11. The method of any one of claims 1 to 10, wherein

The nano-substrate structure is selected from the group consisting of Mn, co, ce, fe, al, ca, cu, ni, ti, zn, si, mo, bi, V, C, N and oxides, nitrides, sulfides, carbides, hydroxides, chlorides, and Metal Organic Frameworks (MOFs), preferably metal organic frameworks, tiO ₂ Or Al ₂ O ₃ 。

12. The method of any one of claims 1 to 11, wherein

The composite catalyst is a catalyst of Co and Fe supported or combined with a metal organic framework, a catalyst of Co and Mn supported or combined with a metal organic framework, and a catalyst of Fe and Co supported or combined with TiO ₂ Is supported on or combined with TiO by Ru and Co ₂ Is a catalyst of (a).

13. The method of any one of claims 1 to 12, wherein

At least one dimension of the nano-substrate structure in length, width, and height is from about 1nm to about 1000nm, preferably from about 70nm to about 1000nm, from about 100nm to about 800nm, and from about 200nm to about 500nm.

14. The method of any one of claims 1 to 13, wherein

The nano-substrate structures are each independently from about 1nm to about 3000nm long, wide, high, preferably from about 100nm to about 3000nm long, from about 500nm to about 2500nm, or from about 1000nm to about 2000nm long, and/or from about 1nm to about 1000nm wide or high, from about 70nm to about 1000nm, from about 100nm to about 800nm, or from about 200nm to about 500nm, or

The nano-substrate structures each independently have an aspect ratio of about 1 to about 20, preferably about 1 to about 10, or about 2 to about 8.

15. The method of any one of claims 1 to 14, wherein

The shape of the nano-substrate structure is spherical, spiny, thin sheet, needle-like, grass leaf, cylindrical, polyhedral, three-dimensional cone, cube, flake, hemispherical, irregular three-dimensional shape, porous structure or any combination thereof.

16. The method of any one of claims 1 to 15, wherein

A plurality of said atomic sites are arranged in a patterned configuration, preferably a multi-layer arrangement, or

A plurality of the atomic sites are randomly dispersed in and/or on the nano-substrate structure.

17. The method of any one of claims 1 to 16, wherein

The energy radiation causes the reaction to proceed at a temperature of between about 20 ℃ and about 500 ℃, preferably between about 50 ℃ and about 300 ℃, between about 70 ℃ and about 250 ℃, between about 90 ℃ and about 200 ℃, between about 100 ℃ and about 180 ℃, between about 110 ℃ and about 160 ℃, between about 120 ℃ and about 150 ℃, between about 130 ℃ and about 150 ℃.

18. The method of any one of claims 1 to 17, wherein

Initiating a reaction using an ultrasonic field in combination with light or heat radiation and allowing the reaction to proceed using the ultrasonic field in combination with light or heat radiation, wherein

The optical radiation power of the optical radiation is 200-1500W/m ² Preferably 200-1000W/m ² Most preferably 500-1000W/m ² 。

19. The method of any one of claims 5 to 18, wherein

The optical radiation increases the temperature of the composite catalyst and the hydrogen-containing source, preferably the only source of increased temperature.

20. The method of any one of claims 1 to 19, wherein

The hydrogen-containing source is selected from the group consisting of water, aldehydes, carboxylic acids and phenols, and any combination thereof, preferably water.