Copper-based catalyst, copper-based catalytic electrode, preparation method thereof, and electrochemical electrolysis device

Abstract

The present invention belongs to the field of electrocatalytic technology, and specifically relates to a copper-based catalyst, a copper-based catalytic electrode, a preparation method thereof, and an electrochemical electrolysis device. In a CO-rich environment, the present invention forms a new copper-based catalyst, which, in addition to copper elements, also contains a regulating metal element with an atomic radius larger than that of copper. The atoms of the regulating metal element are connected to the copper lattice in an atomically homogeneous blending form through metal bonds, and most of the regulating metal element is distributed at the grain boundaries on the surface of the copper lattice, forming a copper-based catalyst component rich in defects, achieving strong *CO bonds and high surface *CO coverage on the copper surface, thereby stabilizing the *OCCO dimer and promoting the subsequent CO-OCCOH coupling to form C3 products, improving the selectivity of single multi-carbon products in the electrochemical reduction reaction of carbon dioxide / monoxide, and increasing the reaction rate, energy conversion efficiency, and reactant conversion rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical catalysis, and specifically relates to providing a copper-based catalyst, a copper-based catalytic electrode, a preparation method thereof, and an electrochemical electrolysis device. Background Art

[0002] The electrochemical reduction reaction of carbon dioxide / carbon monoxide (CO2RR / CORR) is one of the effective ways to mitigate the greenhouse effect, promote carbon cycle, reduce net carbon emissions, and ultimately achieve "carbon neutrality". At the same time, converting carbon dioxide / carbon monoxide into high-value-added raw materials (such as ethanol, n-propanol, etc.) can also efficiently store intermittent energy and increase energy utilization efficiency.

[0003] Among them, copper-based catalysts are commonly used catalysts in the electrochemical reduction reaction of carbon dioxide / carbon monoxide. By adjusting the composition, surface structure and oxidation state of copper-based catalysts, the electrochemical reduction reaction of carbon dioxide / carbon monoxide has achieved low activation energy, low overpotential, and the Faraday efficiency (FE) has been continuously improved. At present, the Faraday efficiency of carbon dioxide reduction to produce C1 and C2 products (such as carbon monoxide and formate) has reached more than 90%. However, for multi-carbon products with higher added value (C3, such as n-propanol, etc.), the product selectivity and the catalytic activity and durability of copper-based catalysts during the reaction process still need to be further improved.

[0004] For example, n-propanol, as a C3 multi-carbon product, is a promising chemical with a wide range of uses, such as feedstock and solvent in pharmaceuticals, plastics industry, and fuels. Nowadays, n-propanol is usually produced through a catalytic hydrogenation step of propionaldehyde followed by a thermal carbonylation reaction of ethylene and carbon monoxide (*CO). It can be directly produced by the electrochemical CO reduction reaction (CORR) under renewable electricity, which is a promising approach to achieve a closed carbon cycle. However, the synthesis of n-propanol using current copper-based catalysts still has limited Faradaic efficiencies (FEs < 40%) and low activities, which seriously hinders its industrial application. The root cause is that the surface *CO coverage of C2 intermediates is insufficient, and the C1-C2 coupling between C2 intermediates and surface-adsorbed *CO is weak, which cannot selectively branch the CORR from ethanol to n-propanol. Summary of the invention

[0005] An object of the present invention is to provide a copper-based catalyst and a preparation method thereof, which can improve the single product selectivity in the carbon dioxide / carbon monoxide electrochemical reduction reaction and reduce the product separation cost.

[0006] Another object of the present invention is to provide a copper-based catalytic electrode and a method for preparing the same. By using the copper-based catalyst of the present invention, the electrochemical properties of the catalytic electrode are improved, the overpotential of the electrochemical reduction reaction of carbon dioxide / carbon monoxide is reduced, and the reaction rate, energy conversion efficiency and reactant conversion rate are increased.

[0007] Another object of the present invention is to provide an electrochemical electrolysis device to reduce the full cell voltage of the carbon dioxide / carbon monoxide electrochemical reduction reaction and improve the reaction rate, energy conversion efficiency and stability.

[0008] The preparation method of the copper-based catalyst provided by the present invention comprises the following specific steps:

[0009] (1) preparing a first solution in which a metal salt precursor is dissolved, wherein the metal salt precursor contains at least one modifier metal element, and the modifier metal element includes at least one transition metal element or main group metal element having an atomic radius larger than copper;

[0010] (2) adding nanometer-scale powder containing copper oxide to the first solution, and further adding a first binder, and stirring to produce a uniformly dispersed mixed slurry;

[0011] (3) spraying or dripping the mixture slurry onto a conductive substrate placed on a hot plate and evaporating the solvent;

[0012] (4) placing the conductive substrate in a corresponding electrolyte, applying a reduction potential to the conductive substrate in an environment where carbon monoxide is continuously introduced, and performing an electrochemical reduction reaction, wherein the reduced copper covers the conductive substrate to form a copper electrode, and the atoms of the regulator metal element are dissolved and deposited in situ on the copper electrode, and further bonded to the copper lattice of the copper electrode, thereby forming a regulator metal element-doped copper-based catalyst, and in the copper-based catalyst, the distribution of the regulator metal element atoms at the grain boundaries of the copper lattice is more enriched than at other positions of the copper lattice;

[0013] The regulator metal element is selected from at least one of Pb, Sb, Sn, In, Au, Bi, Cd and Hg;

[0014] The atomic molar ratio of the copper element in the copper-based catalyst to the metal element of the regulator is 1:Y, wherein Y is 0.005 to 0.1;

[0015] The continuous introduction of carbon monoxide has a flow rate of not less than 20 ml / min;

[0016] The first adhesive is selected from at least one of a Nafion solution, a polyvinylidene fluoride monomer solution and a polytetrafluoroethylene monomer solution.

[0017] Optionally, the step of preparing a first solution in which a metal salt precursor is dissolved comprises:

[0018] (1) mixing water in a polar organic solvent to produce an organic-water mixed solvent;

[0019] (2) Dissolving the metal salt precursor in the organic-water mixed solvent to produce the first solution.

[0020] Optionally, the nanometer-scale powder containing copper oxide is a nanometer-scale powder of copper oxide or a nanometer-scale powder of a copper oxide-carbon carrier composite material. The steps for preparing the nanometer-scale powder of the copper oxide-carbon carrier composite material include:

[0021] (1) dissolving a copper salt precursor in water to produce a copper salt solution;

[0022] (2) mixing an alkali solution with a copper salt solution and stirring to produce a second solution;

[0023] (3) adding the carbon support to the second solution and continuously stirring to produce a uniform mixed solution;

[0024] (4) transferring the uniform mixed solution to a hydrothermal reaction kettle for hydrothermal reaction to obtain a suspension containing a copper oxide-carbon carrier composite material;

[0025] (5) centrifuging the suspension obtained in the hydrothermal reactor to obtain a powder sample;

[0026] (6) Washing, drying and grinding the powder sample to obtain nano-scale powder of copper oxide-carbon carrier composite material.

[0027] Optionally, the carbon carrier is selected from at least one of nano carbon powder, carbon nanotubes, graphene, reduced graphene oxide, conductive carbon black super P, conductive carbon black XC-72, conductive carbon black acetylene black and conductive carbon black BP2000.

[0028] Optionally, in the copper oxide-carbon carrier composite material nanoscale powder, the molar ratio of copper element to carbon element is 1:X, wherein X is 0.2 to 1.2.

[0029] The present invention also provides a copper-based catalyst obtained by the above-mentioned preparation method, which has a copper lattice and atoms of a regulator metal element connected to the copper lattice by metal bonds, wherein the regulator metal element includes at least one transition metal element or main group metal element having an atomic radius larger than that of copper, and the distribution of the atoms of the regulator metal element at the grain boundaries of the copper lattice is more enriched than at other positions of the copper lattice.

[0030] The modifier metal element is selected from at least one of Pb, Sb, Sn, In, Au, Bi, Cd and Hg.

[0031] The atomic molar ratio of the copper element in the copper-based catalyst to the regulator metal element is 1:Y, wherein Y is 0.005 to 0.1.

[0032] Optionally, the copper-based catalyst further has a nanoscale carbon carrier, and the molar ratio of the copper element in the copper-based catalyst to the carbon element in the carbon carrier is 1:X, wherein X is 0.2 to 1.2.

[0033] Optionally, the carbon carrier is selected from at least one of nano carbon powder, carbon nanotubes, graphene, reduced graphene oxide, conductive carbon black super P, conductive carbon black XC-72, conductive carbon black acetylene black and conductive carbon black BP2000.

[0034] The copper-based catalyst prepared by the invention has excellent catalytic performance.

[0035] The present invention also provides a method for preparing a copper-based catalytic electrode, which comprises the following steps:

[0036] First, the copper-based catalyst is prepared on a conductive substrate using the method for preparing the copper-based catalyst of the present invention as an electrode substrate;

[0037] Next, the electrode substrate is washed and dried to obtain a copper-based catalytic electrode; wherein the conductive substrate is selected from one of conductive glass, conductive metal sheet and stainless steel plate, the thickness of the conductive substrate is 0.5 mm to 2.0 mm, and the loading amount of the copper-based catalyst in the copper-based catalytic electrode is 0.2 mg / cm 2 ~5.0 mg / cm 2 .

[0038] The present invention also provides a copper-based catalytic electrode obtained by the method.

[0039] The present invention also provides a method for preparing a copper-based catalytic electrode as a gas diffusion electrode, which comprises the following steps:

[0040] First, the method for preparing the copper-based catalyst of the present invention is used to obtain an electrode substrate containing the copper-based catalyst;

[0041] Then, the copper-based catalyst layer in the electrode matrix is ​​peeled off from the conductive substrate, and the peeled copper-based catalyst is washed and then mixed with water, a second binder and an organic solvent to produce a catalyst slurry;

[0042] Next, the catalyst slurry is sprayed or dripped onto the conductive diffusion layer and the slurry is dried to form a gas diffusion electrode covered with a copper-based catalyst layer.

[0043] The second adhesive is selected from at least one of Nafion solution, polyvinylidene fluoride monomer solution, polytetrafluoroethylene monomer solution, polyethylene-tetrafluoroethylene copolymer monomer solution, and Dowex ion exchange resin solution, and the organic solvent is selected from at least one of ethanol, methanol, n-propanol, isopropanol, ethylene glycol, glycerol, acetone, and N,N-dimethylformamide.

[0044] The conductive diffusion layer can be selected from hydrophobic carbon paper, thermally evaporated copper PTFE film or ion beam sputtered copper PTFE film, and the thickness of the conductive diffusion layer is 0.1 mm to 2.0 mm, and the loading amount of the copper-based catalyst in the formed gas diffusion electrode is 1 mg / cm 2 ~10mg / cm 2 .

[0045] The present invention also provides a copper-based catalytic electrode obtained by the above method, namely a gas diffusion electrode.

[0046] The present invention also provides an electrochemical electrolysis device, which uses the copper catalyst described in the present invention as an electrode catalyst; or, the electrochemical electrolysis device has the copper-based catalytic electrode described in the present invention and also has an oxygen-producing electrode or a urea oxidation electrode.

[0047] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0048] 1. The copper-based catalyst and preparation method provided by the present invention form a new copper-based catalyst in a CO (carbon monoxide)-rich environment. In addition to the copper element, the catalyst also contains a regulator metal element with an atomic radius larger than that of the copper atom. The atoms of the regulator metal element are connected to the copper lattice in an atomically homogeneous mixed form through metal bonds, and most of the regulator metal element is distributed at the grain boundaries on the surface of the copper lattice, forming a copper-based catalyst component with rich defects at the grain boundaries, achieving a strong *CO bond and a high surface *CO coverage on the copper surface, which stabilizes the *OCCO dimer and promotes the subsequent CO-OCCOH coupling to form a C3 product, thereby improving the selectivity of a single multi-carbon product in the carbon dioxide / carbon monoxide electrochemical reduction reaction, and improving the reaction rate, energy conversion efficiency and reactant conversion rate;

[0049] 2. The preparation process is simple, the cost is low, and it can achieve high-activity and high-stability carbon dioxide / carbon monoxide electrochemical reduction reaction, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flow chart of a method for preparing a copper-based catalyst according to a specific embodiment of the present invention.

[0051] Figure 2 This is a scanning electron microscope (SEM) photograph of nanometer-scale powder particles of a copper oxide-carbon carrier composite material used in the method for preparing a copper-based catalyst according to a specific embodiment of the present invention.

[0052] Figure 3 It is a schematic diagram of atomic-level changes of substances in the method for preparing a copper-based catalyst according to a specific embodiment of the present invention.

[0053] Figure 4 This is a scanning electron microscope (SEM) photograph of the copper-based catalyst powder particles obtained in a specific embodiment of the present invention.

[0054] Figure 5 This is a scanning transmission electron microscope high-angle annular dark field (STEM-HAADF) photograph of the copper-based catalyst powder obtained in a specific embodiment of the present invention, wherein Figure a is a STEM-HAADF photograph, and Figures b and c are STEM photographs at different atomic-level resolutions, respectively.

[0055] Figure 6 It is an energy spectrum (EDX) distribution diagram with a scale of 100 nm, wherein Figure a is an energy spectrum distribution diagram of the entire copper-based catalyst obtained in a specific embodiment of the present invention, Figure b is an energy spectrum distribution diagram of the copper-lead alloy in the copper-based catalyst; Figure c is an energy spectrum distribution diagram of copper in the copper-based catalyst; Figure d is an energy spectrum distribution diagram of lead in the copper-based catalyst.

[0056] Figure 7 This is the in-situ X-ray absorption spectrum of the copper-based catalyst obtained in a specific embodiment of the present invention in the electrochemical reduction reaction of carbon monoxide, wherein Figure a is the X-ray absorption fine structure spectrum (EXAFS) of the Cu K edge; Figure b is the X-ray absorption near edge spectrum (XANES) of the Pb L3 edge.

[0057] Figure 8 The electrochemical performance of the copper-based catalytic electrode obtained in the specific embodiment 1 of the present invention in the electrochemical reduction reaction of carbon monoxide, wherein Figure a shows the C 2+ Product distribution; Figure b shows the Faraday efficiency and partial current density of n-propanol at different potentials; Figure c shows the current curve and Faraday efficiency of n-propanol in the stability test using constant potential mode. The electrolyte is 1 M KOH aqueous solution, and the potential of the constant voltage test is -0.68 V (relative to the reversible hydrogen electrode, RHE).

[0058] Fig. 9 The copper-based catalytic electrode obtained in the specific embodiment of the present invention is used as a cathode in an alkaline system polymer anion exchange membrane carbon monoxide reduction reaction device, and the voltage curve and the Faraday efficiency of all products obtained by stability testing in constant current mode are shown in the figure. The current density is 200 mA / cm2 .

[0059] Fig.10 The electrochemical performance of the copper-based catalytic electrode obtained in the specific embodiment 2 of the present invention in the electrochemical reduction reaction of carbon monoxide, wherein a is the product distribution at different potentials, and b is the partial current density of n-propanol at different potentials.

[0060] Fig.11 The electrochemical performance of the copper-based catalytic electrode obtained in the specific embodiment 3 of the present invention in the electrochemical reduction reaction of carbon monoxide. Wherein, a is the product distribution at different potentials, and b is the partial current density of n-propanol at different potentials.

[0061] Fig.12 The electrochemical performance of the copper-based catalytic electrode obtained in the specific embodiment 4 of the present invention in the electrochemical reduction reaction of carbon monoxide is shown in FIG. DETAILED DESCRIPTION

[0062] At present, the copper-based catalysts for the electrochemical reduction reaction of carbon dioxide / carbon monoxide (CO2RR / CORR) that have been successfully developed still face challenges in the selectivity for single multi-carbon products such as n-propanol, as well as the activity and long-term stability of the catalyst due to the random adsorption of reaction intermediates on their surfaces and the phase separation phenomenon during the reaction, which limits the development of the industry.

[0063] The core of the technical solution of the present invention is to provide a copper-based catalyst, an electrode and a preparation method thereof and an electrochemical electrolysis device. A new copper-based catalyst is formed in a CO (carbon monoxide)-rich environment. In addition to the copper element, the catalyst also contains a regulator metal element with an atomic radius larger than that of copper. The atoms of the regulator metal element are connected to the copper lattice in an atomically homogeneous mixed form through metal bonds, and most of the atoms of the regulator metal element are distributed at the grain boundaries on the surface of the copper lattice, forming a copper-based catalyst component with rich defects at the grain boundaries, achieving a strong *CO bond and a high surface *CO coverage on the copper surface, which stabilizes the *OCCO dimer and promotes the subsequent CO-OCCOH coupling to form a C3 product, thereby improving the selectivity of a single multi-carbon product in the carbon dioxide / carbon monoxide electrochemical reduction reaction, and improving the reaction rate, energy conversion efficiency and reactant conversion rate. The copper-based catalyst of the present invention is detected by experimental detection techniques such as XRD, TEM, and XAFS. There is interaction between copper atoms, between copper atoms and atoms of the regulator metal element, and between the copper alloy and the carbon carrier, which is conducive to regulating the adsorption energy of the intermediate of the carbon dioxide / carbon monoxide electrochemical reduction reaction, thereby improving the activity of the catalyst in the carbon dioxide / carbon monoxide electrochemical reduction reaction. And the interaction between the copper alloy and the carbon carrier overcomes the phase separation problem of the metal solid solution in the catalytic reaction process, promotes the atoms of the regulator metal element to be stably present in the copper-based catalyst in the form of atomic-level homogeneous blending, and effectively improves the stability of the copper-based catalyst. This copper-based catalyst has excellent carbon dioxide / carbon monoxide electrochemical reduction reaction performance and excellent stability.

[0064] In order to make the purpose and features of the present invention more obvious and understandable, the specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. However, the present invention can be implemented in different forms and should not be limited to the implementation cases described. Unless otherwise specified, all applied voltages in this work refer to the reversible hydrogen electrode (RHE) without iR compensation.

[0065] Please refer to Figure 1 An embodiment of the present invention provides a method for preparing a copper-based catalyst, which comprises the following steps:

[0066] S1, preparing a first solution in which a metal salt precursor is dissolved, wherein the metal salt precursor contains at least one modifier metal element J, and the modifier metal element J includes at least one transition metal element or main group metal element having an atomic radius larger than copper;

[0067] S2, adding nanometer-scale powder containing copper oxide to the first solution, and further adding a first binder D and stirring to produce a uniformly dispersed mixed slurry;

[0068] S3, spraying or dripping the mixture slurry onto a conductive substrate E placed on a hot stage and evaporating the solvent;

[0069] S4, placing the conductive substrate E in a corresponding electrolyte F, applying a reduction potential to the conductive substrate in an environment where carbon monoxide is continuously introduced, performing an electrochemical reduction reaction, and the reduced copper covers the conductive substrate to form a copper electrode, and the atoms of the regulator metal element are dissolved and deposited in situ on the copper electrode and further bonded to the copper lattice of the copper electrode, thereby forming a regulator metal element-doped copper-based catalyst, and in the copper-based catalyst, the distribution of the regulator metal element atoms at the grain boundaries of the copper lattice is more enriched than at other positions of the copper lattice.

[0070] In step S1, the step of preparing a first solution in which a metal salt precursor is dissolved comprises:

[0071] S1.1, mixing a certain amount of water in a polar organic solvent A to produce an organic-water mixed solvent B, wherein the polar organic solvent A includes at least one of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, glycerol, and acetone. When a certain amount of water is mixed in the polar organic solvent A to produce the organic-water mixed solvent B, the amount of water required is determined by the solubility of the metal precursor salt of the regulator metal element in the mixed solvent;

[0072] S1.2, fully dissolving a metal salt precursor containing at least one modifier metal element in an organic-water mixed solvent B by ultrasonic technology to produce a first solution. The modifier metal element J includes at least one transition metal element or main group metal element with an atomic radius larger than copper Cu, and the modifier metal element J is selected from at least one of Pb, Sb, Sn, In, Au, Bi, Cd and Hg. The metal salt precursor C includes one or at least two of metal halides, metal nitrates, metal sulfates, metal phosphates, metal alkoxides and metal esters.

[0073] In step S2, the nano-scale powder containing copper oxide is a nano-scale powder of copper oxide or a nano-scale powder of a copper oxide-carbon carrier composite material. The steps for preparing the nano-scale powder of the copper oxide-carbon carrier composite material include:

[0074] S2.1, dissolving a copper salt precursor G in water to produce a copper salt solution, wherein the copper salt precursor is selected from at least one of copper halide, copper nitrate, copper sulfate, copper phosphate and copper perchlorate;

[0075] S2.2, mixing an alkali solution H with the copper salt solution and stirring the mixture with ultrasound to produce a second solution, wherein the alkali solution H is a potassium hydroxide solution or a sodium hydroxide solution or a mixture of the two solutions;

[0076] S2.3, adding a carbon carrier C to the second solution, and continuously stirring with ultrasound to produce a uniform mixed solution, wherein the carbon carrier is selected from at least one of nano carbon powder, carbon nanotubes, graphene, reduced graphene oxide, conductive carbon black super P, conductive carbon black XC-72, conductive carbon black acetylene black and conductive carbon black BP2000;

[0077] S2.4, transferring the uniform mixed solution to a hydrothermal reactor for hydrothermal reaction to obtain a suspension containing a copper oxide-carbon carrier composite material;

[0078] S2.5, centrifuging the suspension obtained in the hydrothermal reactor to obtain a powder sample;

[0079] S2.6, soaking the powder sample in water for washing to remove unreacted copper salt precursor G from the powder sample, and then drying and grinding the powder sample without annealing to obtain a copper oxide-carbon carrier composite material nano-scale powder, wherein the copper oxide-carbon carrier composite material nano-scale powder has a molar ratio of copper element to carbon element of 1:X, wherein X is 0.2 to 1.2. The particles of the prepared copper oxide-carbon carrier composite material nano-scale powder present a flaky structure with a particle size of about 300 nm, such as Figure 2 shown.

[0080] Among them, the carbon carrier can provide the voltage of the final copper-based catalyst in the actual carbon monoxide / carbon dioxide reduction reaction, thereby improving the output efficiency of multi-carbon products.

[0081] In step S2, after the required copper oxide-carbon carrier composite material nanopowder is prepared, it is added to the first solution prepared in step S1, and a first binder D is further added for ultrasonic stirring to produce a uniformly dispersed mixed slurry. The first binder D is selected from one of Nafion solution, polyvinylidene fluoride monomer solution and polytetrafluoroethylene monomer solution.

[0082] In step S3, the mixture slurry obtained in step S2 is sprayed or dripped onto a conductive substrate E placed on a hot stage and the organic solvent in the mixture slurry is fully evaporated. The conductive substrate E is selected from conductive glass, conductive metal sheet or stainless steel plate. The thickness of the conductive substrate is 0.5 mm to 2.0 mm.

[0083] In step S4, the acidity and alkalinity of the selected electrolyte F needs to be determined by the solubility of the metal ions of the regulator metal element. The electrolyte F includes at least one of potassium hydroxide solution, sodium hydroxide solution, cesium hydroxide solution, sulfuric acid, perchloric acid, hydrochloric acid, potassium bicarbonate solution, and potassium carbonate solution. The flow rate of continuous introduction of carbon monoxide is not less than 20 ml / min. Apply the required reduction potential (relative to the potential of the reversible hydrogen electrode RHE) to the conductive substrate E, and control the reaction time to perform an electrochemical reduction reaction, please refer to Figure 3 , copper Cu reduced from copper oxide CuO forms a copper electrode on the conductive substrate E, and atoms of the modifier metal element J are dissolved and deposited in situ on the copper electrode and further bonded to the copper lattice of the copper electrode, thereby forming a copper-based catalyst doped with the modifier metal element J. The formed copper-based catalyst powder is in the form of nanoparticles with a size of about 200 nm. The doping of modifier metal element J atoms causes a slight lattice expansion of the Cu lattice, and the Cu lattice doped with modifier metal element J atoms is slightly larger than the standard lattice constant in the pure Cu catalyst, and the distribution of modifier metal element J atoms at the grain boundaries of the copper lattice of the copper-based catalyst is more enriched than other positions of the copper lattice.

[0084] The present invention also provides a copper-based catalyst, which can be prepared by the method for preparing the copper-based catalyst of this embodiment. The copper-based catalyst has a copper lattice and a modifier metal element J atom connected to the copper lattice by a metal bond, the modifier metal element J includes at least one transition metal element or main group metal element having an atomic radius larger than that of copper, and the distribution of the modifier metal element J atoms at the grain boundary of the copper lattice is more enriched than at other positions of the copper lattice.

[0085] Optionally, the modifier metal element J is selected from at least one of Pb, Sb, Sn, In, Au, Bi, Cd and Hg.

[0086] Optionally, the atomic molar ratio of the copper element in the copper-based catalyst to the regulator metal element is 1:Y, wherein Y is 0.005 to 0.1.

[0087] Optionally, the copper-based catalyst further comprises a nanoscale carbon carrier, and the molar ratio of the copper element in the copper-based catalyst to the carbon element in the carbon carrier is 1:X, wherein X is 0.2 to 1.2. The carbon carrier is selected from at least one of nano-carbon powder, carbon nanotubes, graphene, reduced graphene oxide, conductive carbon black super P, conductive carbon black XC-72, conductive carbon black acetylene black, and conductive carbon black BP2000.

[0088] The present invention also provides a method for preparing a copper-based catalytic electrode, which comprises the following steps:

[0089] First, the method for preparing the copper-based catalyst of the present invention is used to obtain an electrode substrate containing the copper-based catalyst;

[0090] Next, the electrode substrate is washed and dried to obtain a copper-based catalytic electrode; wherein the conductive substrate E is selected from one of conductive glass, conductive metal sheet and stainless steel plate, the thickness of the conductive substrate E is 0.5 mm to 2.0 mm, and the loading amount of the copper-based catalyst in the copper-based catalytic electrode is 0.2 mg / cm 2 ~5.0 mg / cm 2 .

[0091] The present invention also provides a copper-based catalytic electrode, which can be prepared by the above-mentioned method for preparing a copper-based catalytic electrode. The copper-based catalytic electrode comprises a conductive substrate E and a copper-based catalyst covered on the conductive substrate E as described in the present invention.

[0092] The present invention also provides a method for preparing a copper-based catalytic electrode as a gas diffusion electrode, which comprises the following steps:

[0093] First, the method for preparing the copper-based catalyst of the present invention is used to obtain an electrode substrate containing the copper-based catalyst;

[0094] Then, the copper-based catalyst layer in the electrode matrix is ​​peeled off from the conductive substrate E, and the peeled copper-based catalyst is washed and then mixed with water, a second adhesive and an organic solvent to produce a catalyst slurry, wherein the second adhesive is selected from at least one of a Nafion solution, a polyvinylidene fluoride monomer solution, a polytetrafluoroethylene monomer solution, a polyethylene-tetrafluoroethylene copolymer monomer solution, and a Dowex ion exchange resin solution, and the organic solvent is selected from at least one of ethanol, methanol, n-propanol, isopropanol, ethylene glycol, glycerol, acetone and N,N-dimethylformamide;

[0095] Next, the catalyst slurry is sprayed or dripped onto the conductive diffusion layer and the slurry is dried to form a gas diffusion electrode covered with a copper-based catalyst layer. The conductive diffusion layer can be selected from hydrophobic carbon paper, a PTFE film with thermal evaporation copper, or a PTFE film with ion beam sputtering copper, and the thickness of the conductive diffusion layer is 0.1 mm to 2.0 mm. The loading amount of the copper-based catalyst in the formed gas diffusion electrode is 1 mg / cm 2 ~10mg / cm 2 .

[0096] The present invention also provides a copper-based catalytic electrode, which is a gas diffusion electrode and can be prepared using the above-mentioned method for preparing a copper-based catalytic electrode as a gas diffusion electrode. The copper-based catalytic electrode may include a conductive diffusion layer and a copper-based catalyst as described in the present invention covering the conductive diffusion layer.

[0097] Example 1, using Pb as a regulator metal element to form a copper-based catalyst and a copper-based catalytic electrode, and its technical effect.

[0098] 1. Preparation of Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) and copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode)

[0099] (1) Preparation of copper oxide-carbon carrier composite nanopowder: Weigh 2.40 g of sodium hydroxide, 1.02 g of copper salt, and 50 mg of nanocarbon powder, dissolve them in 30 ml of deionized water, stir them thoroughly, and transfer the mixed solvent to a hydrothermal reactor; place the reactor in a high-temperature oven and keep it at a constant temperature of 130 °C for 12 h; centrifuge, wash, dry, and grind the obtained samples, respectively. Figure 2 As shown, the particles of the prepared copper oxide-carbon carrier composite nanopowder present a flaky structure, and the particle size is about 300 nm;

[0100] (2) Preparation of Pb(NO3)2 methanol solution: weigh 3 mg Pb(NO3)2, dissolve it in 1 ml methanol, and sonicate for 0.5 h to fully dissolve it;

[0101] (3) Preparation of copper oxide suspension: Weigh 15 mg of the copper oxide-carbon carrier composite nanopowder, add it to 1 ml of the prepared Pb(NO3)2 methanol solution, and add 50 μl of perfluorosulfonic acid resin monomer solution (5wt%), and ultrasonicate the mixed liquid for 60 min until it is evenly dispersed;

[0102] (4) Preparation of Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) and electrode (i.e., Cu-Pb catalytic electrode): 1 ml of the above suspension was dropped onto a 4 cm 2 The gas diffusion layer (Freudenberg H23C9) was placed on a hot plate at 50 °C to evaporate the methanol. -1 In potassium hydroxide solution, at a rate of 20 ml min -1 A carbon monoxide environment was introduced at a flow rate of 0.28 V (relative to the reversible hydrogen electrode, RHE) and the reaction time was controlled to be 100 s. 2+ After dissolution, the Pb-doped copper-based catalyst is in-situ deposited on the surface of the copper electrode obtained by electroreduction at a reduction potential to obtain a gas diffusion electrode loaded with a Pb-doped copper-based catalyst. Figures 4 to 5As shown, the Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) is in the form of nanoparticles with a size of about 200 nm. The lattice of the Pb-doped Cu-based catalyst is slightly larger than the standard lattice constant of the Cu catalyst, proving that Pb doping causes a slight expansion of the Cu lattice.

[0103] 2. Performance analysis of the prepared Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) and copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode);

[0104] We have analyzed the relevant technical means for the prepared Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) and copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode), as follows:

[0105] Among them, please refer to Figure 6 and Figure 7 The X-ray diffraction (XRD) patterns of the Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) and the copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode) show that there is no crystalline Pb feature inside the Cu lattice, which is similar to the pure copper lattice. The XRD characteristic peak corresponding to the (111) plane slightly shifts to the low-angle region, indicating a slight lattice expansion of the Pb-doped copper-based catalyst sample. This is because Pb doping causes a slight lattice expansion of Cu, making the lattice of the Pb-doped Cu-based catalyst slightly larger than the standard lattice constant of the pure Cu catalyst. Figure 7 a and Figure 7 From the analysis in b, we can see that Pb is doped into the Cu lattice at the atomic level, and both Cu and Pb exist in a metallic valence state during the CORR process.

[0106] Analysis of high-resolution TEM (HRTEM) images (not shown) and corresponding SAED patterns (not shown) revealed that the surface of the Pb-doped copper-based catalyst Cu-Pb exhibited a denser band structure and grain boundaries (GBs), which indicated that the Pb-doped copper-based catalyst had defect-rich characteristics.

[0107] Please refer to Figure 5 , high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image analysis revealed that the Pb-doped Cu-based catalyst had an average particle size of about 20 nm and abundant GBs, in which Pb atoms were distributed at the atomic level in the Cu lattice.

[0108] Please refer to Figure 6 , high-resolution EDX elemental image analysis shows that the Pb atomic density near the GBs of the Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) is higher, indicating that Pb doping can promote the formation of GBs. Figure 6From the analysis, it can be seen that the Cu and Pb elements are distributed at the atomic level in the lattice of the copper-based catalyst, and the atomic ratio of Pb is about 1%.

[0109] The analysis of inductively coupled plasma emission spectrometer (ICP-OES) shows that the average Pb atomic ratio in the Pb-doped copper-based catalyst (i.e., Cu-Pb catalyst) is about 2.9%, which further confirms the presence of Cu and Pb in the Pb-doped copper-based catalyst sample. In addition, the analysis of high-resolution X-ray photoelectron spectroscopy (XPS) shows that the content of Pb atoms near the surface of the Cu lattice is about 8%, which is significantly greater than the content of Pb atoms in other positions of the Cu lattice. This shows that Pb doping mainly occurs near the surface of the copper lattice (or the copper electrode surface), with a depth of about 30nm, please refer to Figure 3 shown.

[0110] In addition, in order to gain a deeper understanding of the adsorption characteristics of defect-rich Pb-doped copper-based catalyst surfaces, an operational electrochemical attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) analysis was also performed under CORR conditions. The results showed that the adsorption of 2027-2080 cm -1 The adsorption bonds in the range are attributed to the binding of *CO on the top of the Cu lattice (*COtop, referred to as *CO top). The *COtop on the Cu-Pb surface is divided into two bands, and we divide the 2027~2067 cm -1 The wavelength band at 2075-2080 cm is called the low frequency band (LFB). -1 The band at the bottom is called the high frequency band (HFB). LFB and HFB are attributed to *COtop at terraces and defect sites, respectively. The presence of bridge-bound *CO (*CObridge, referred to as *CO bridge) on the Cu-Pb surface was also observed. Obviously, more defects on the Pb-doped copper-based catalyst samples enable a variety of CO adsorption configurations.

[0111] 3. Assembly and performance testing of the CO2RR / CORR three-phase flow system based on Pb-doped copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode);

[0112] Specifically, a gas diffusion electrode loaded with Pb-doped copper-based catalyst (i.e., nanomaterial of Cu-Pb catalyst) was used as cathode, nickel foam with electrodeposited Fe was used as anode, mercury / mercury oxide electrode was used as reference electrode, and FAB-PK-130 anion exchange membrane was used as diaphragm. 1 mol / L potassium hydroxide was passed through both sides of the diaphragm as anode and cathode electrolyte, respectively. The catalyst layer of the gas diffusion electrode faced the cathode electrolyte, and carbon monoxide was passed through the back side to assemble a CORR three-phase flow system device, and electrochemical tests were carried out.

[0113] like Figure 8As shown in a, in a wide potential window of -0.38~-0.98 V (vs. reversible hydrogen electrode, RHE), C 2+ The selectivity is above 90%; Figure 8 b. At a potential of -0.68 V (vs. RHE), the Faradaic efficiency of n-propanol reaches 46.6%, and the maximum partial current density of n-propanol reaches 43.9 mA cm -2 .like Figure 8 c, The activity of the Pb-doped copper-based catalyst at a constant potential of -0.68 V (vs. RHE) did not decrease significantly within 10 h, and the n-propanol selectivity remained above 40%. This is far beyond the performance of existing n-propanol selective catalysts.

[0114] 4. Assembly and performance testing of a polymer anion exchange membrane CO2RR / CORR device based on a Pb-doped copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode);

[0115] Specifically, a copper-based catalytic electrode loaded with a Pb-doped copper-based catalyst (i.e., a nanomaterial of a Cu-Pb catalyst) was used as a cathode, a nickel foam with electrodeposited Fe was used as an anode, a Sustainion X37-FA anion exchange membrane was used as a diaphragm, a titanium plate or a graphite plate engraved with a flow field was used as a cathode and anode end plate, 1 mol / L potassium hydroxide was introduced into the anode as an electrolyte, and CO was introduced into the cathode end plate as a reaction gas to assemble a polymer anion exchange membrane water electrolysis device, and electrochemical tests were performed.

[0116] like Fig. 9 As shown, at 200 mA / cm 2 Under constant current, the device can work stably for more than 100 h and maintain nearly 95% C 2+ The selectivity of n-propanol is higher than 30%, which far exceeds the performance of existing n-propanol selective catalysts.

[0117] Moreover, the corresponding operational Raman spectroscopy, infrared absorption spectroscopy and density functional theory calculation analysis show that in the copper-based catalyst of the present invention, Pb atoms are doped to form a large number of defect sites, and the defect-rich Pb-doped Cu lattice surface grain boundaries and defects achieve strong *CO bonds and high surface *CO coverage, allowing the adsorption and binding of *CO of various configurations, which stabilizes the *OCCO dimers (i.e., intermediates) in CO2RR and CORR and promotes the subsequent CO-OCCOH coupling (i.e., C1-C2 coupling) from C2 to C3 product formation, and in a membrane electrode assembly (MEA) with a total current of 1A, a stable CO to n-propanol FE of more than 30% is obtained for more than 100 hours, which will greatly improve the rational catalyst design for CO-n-propanol electrosynthesis and the industrial utilization of CO2RR and CORR.

[0118] Example 2: Using Sn as a regulator metal element to form a copper-based catalyst and a copper-based catalytic electrode, and its technical effect.

[0119] 1. Prepare Sn-doped copper-based catalyst (i.e., Cu-Pb catalyst) and copper-based catalytic electrode (i.e., Cu-Pb catalytic electrode);

[0120] (1) Preparation of copper oxide-carbon carrier composite nanopowder: Weigh 2.40 g of sodium hydroxide, 1.02 g of copper salt, and 50 mg of nanocarbon powder, dissolve them in 30 ml of deionized water, stir them thoroughly, and transfer the mixed solvent to a hydrothermal reactor; place the reactor in a high-temperature oven and keep it at a constant temperature of 200 °C for 3 h; centrifuge, wash, dry, and grind the obtained samples, respectively. Figure 2 As shown, the particles of the prepared copper oxide-carbon carrier composite nanopowder present a flaky structure, and the particle size is about 300 nm;

[0121] (2) Prepare a water-methanol mixed solution of SnCl2: weigh 5 mg SnCl2, dissolve it in 0.8 ml methanol and 0.2 ml water, and sonicate for 0.5 h to fully dissolve it;

[0122] (3) Preparation of copper oxide suspension: Weigh 15 mg of the copper oxide-carbon carrier composite nanopowder, add it to 1 ml of the prepared SnCl2 water-methanol mixed solution, and add 80 μl of perfluorosulfonic acid resin monomer solution (5wt%), and sonicate the mixed liquid for 60 min until it is evenly dispersed;

[0123] (4) Preparation of Sn-doped copper-based catalyst (i.e., Cu-Sn catalyst) and electrode (i.e., Cu-Sn catalytic electrode): 1 ml of the above suspension was dropped onto a 4 cm 2The gas diffusion layer (Freudenberg H23C9) was placed on a hot plate at 50 °C to evaporate water and methanol. -1 Potassium hydroxide solution was added at a rate of 20 ml min -1 A carbon monoxide environment was introduced at a flow rate of 1.5 wt %. A potential of -0.35 V (relative to the reversible hydrogen electrode, RHE) was applied to the carbon monoxide. The reaction time was controlled to be 100 s. 2+ After dissolution, the Sn-doped copper-based catalyst is in-situ deposited on the surface of the copper electrode obtained by electroreduction at a reduction potential to obtain a gas diffusion electrode loaded with Sn-doped copper-based catalyst.

[0124] 2. Assembly and performance testing of the CO2RR / CORR three-phase flow system based on Sn-doped copper-based catalytic electrode (i.e., Cu-Sn catalytic electrode);

[0125] Specifically, a gas diffusion electrode loaded with Sn-doped copper-based catalyst (i.e., nanomaterial of Cu-Sn catalyst) was used as cathode, nickel foam with electrodeposited Fe was used as anode, mercury / mercury oxide electrode was used as reference electrode, and FAB-PK-130 anion exchange membrane was used as diaphragm. 1 mol / L potassium hydroxide was passed through both sides of the diaphragm as anode and cathode electrolyte, respectively. The catalyst layer of the gas diffusion electrode faced the cathode electrolyte, and carbon monoxide was passed through the back side to assemble a CORR three-phase flow system device, and electrochemical tests were carried out.

[0126] like Fig.10 As shown in a, in a wide potential window of -0.58~-0.98 V (vs. reversible hydrogen electrode, RHE), C 2+ The selectivity is above 60%. At a potential of -0.68 V (vs. RHE), the Faradaic efficiency of n-propanol reaches 35.5%. Fig.10 b, the highest partial current density of n-propanol reaches 25.5 mA cm -2 .

[0127] Example 3, using Bi as a regulator metal element to form a copper-based catalyst and a copper-based catalytic electrode, and its technical effect.

[0128] 1. Preparation of Bi-doped copper-based catalyst (i.e., Cu-Bi catalyst) and copper-based catalytic electrode (i.e., Cu-Bi catalytic electrode);

[0129] (1) Preparation of copper oxide-carbon carrier composite nanopowder: Weigh 2.40 g of sodium hydroxide, 1.02 g of copper salt, and 50 mg of nanocarbon powder, dissolve them in 30 ml of deionized water, stir them thoroughly, and transfer the mixed solvent to a hydrothermal reactor; place the reactor in a high-temperature oven and keep it at a constant temperature of 200 °C for 3 h; centrifuge, wash, dry, and grind the obtained samples, respectively. Figure 2 As shown, the particles of the prepared copper oxide-carbon carrier composite nanopowder present a flaky structure, and the particle size is about 300 nm;

[0130] (2) Preparation of Bi(NO3)2 water-methanol mixed solution: Weigh 5 mg Bi(NO3)2, dissolve it in 0.7 ml methanol and 0.3 ml water, and sonicate for 0.5 h to fully dissolve it;

[0131] (3) Preparation of copper oxide suspension: Weigh 15 mg of the copper oxide-carbon carrier composite nanopowder, add it to 1 ml of the prepared Bi(NO3)2 water-methanol mixed solution, and add 80 μl of perfluorosulfonic acid resin monomer solution (5wt%), and sonicate the mixed liquid for 60 min until it is evenly dispersed;

[0132] (4) Preparation of Bi-doped copper-based catalyst (Cu-Bi catalyst) and electrode (Cu-Bi catalytic electrode): 1 ml of the above suspension was dropped onto a 4 cm 2 The gas diffusion layer (Freudenberg H23C9) was placed on a hot plate at 50 °C to evaporate water and methanol. -1 In potassium hydroxide solution, at a rate of 20 ml min -1 A gas diffusion electrode loaded with Bi-doped copper-based catalyst was obtained by passing carbon monoxide into the gas diffusion electrode at a flow rate of -0.48 V (relative to reversible hydrogen electrode, RHE) and applying a potential of -0.48 V (relative to reversible hydrogen electrode, RHE). The reaction time was controlled to be 100 s.

[0133] 2. Assembly and performance testing of the CO2RR / CORR three-phase flow system based on Bi-doped copper-based catalytic electrode (i.e., Cu-Bi catalytic electrode);

[0134] Specifically, a gas diffusion electrode loaded with Bi-doped copper-based catalyst (i.e., nanomaterial of Cu-Bi catalyst) was used as cathode, nickel foam with electrodeposited Fe was used as anode, mercury / mercury oxide electrode was used as reference electrode, and FAB-PK-130 anion exchange membrane was used as diaphragm. 1 mol / L potassium hydroxide was passed through both sides of the diaphragm as anode and cathode electrolyte, respectively. The catalyst layer of the gas diffusion electrode faced the cathode electrolyte, and carbon monoxide was passed through the back side to assemble a CORR three-phase flow system device, and electrochemical tests were carried out.

[0135] like Fig.11 As shown in a, in a wide potential window of -0.58~-0.98 V (vs. reversible hydrogen electrode, RHE), C 2+ The selectivity is above 65%. At a potential of -0.68 V (vs. RHE), the Faradaic efficiency of n-propanol reaches 28.5%. Fig.11 b, the highest partial current density of n-propanol reaches 24.9 mA cm -2 .

[0136] Example 4, using In as a regulator metal element to form a copper-based catalyst and a copper-based catalytic electrode, and its technical effect.

[0137] 1. Preparation of In-doped copper-based catalyst (i.e., Cu-In catalyst) and copper-based catalytic electrode (i.e., Cu-In catalytic electrode);

[0138] (1) Preparation of copper oxide-carbon carrier composite nanopowder: Weigh 2.40 g of sodium hydroxide, 1.02 g of copper salt, and 50 mg of nanocarbon powder, dissolve them in 30 ml of deionized water, stir them thoroughly, and transfer the mixed solvent to a hydrothermal reactor; place the reactor in a high-temperature oven and keep it at a constant temperature of 200 °C for 3 h; centrifuge, wash, dry, and grind the obtained samples, respectively. Figure 2 As shown, the particles of the prepared copper oxide-carbon carrier composite nanopowder present a flaky structure, and the particle size is about 300 nm;

[0139] (2) Preparation of a water-methanol mixed solution of In(NO3)3: Weigh 5 mg In(NO3)3 and dissolve it in 0.8 ml methanol and 0.2 ml water. Ultrasonicate for 0.5 h to fully dissolve it.

[0140] (3) Preparation of copper oxide suspension: Weigh 15 mg of the copper oxide-carbon carrier composite nanopowder, add it to 1 ml of the prepared In(NO3)3 water-methanol mixed solution, and add 80 μl of perfluorosulfonic acid resin monomer solution (5wt%), and sonicate the mixed liquid for 60 min until it is evenly dispersed;

[0141] (4) Preparation of In-doped copper-based catalyst (i.e., Cu-In catalyst) and electrode (i.e., Cu-In catalytic electrode): 1 ml of the above suspension was dropped onto a 4 cm 2 The gas diffusion layer (Freudenberg H23C9) was placed on a hot plate at 50 °C to evaporate water and methanol. -1 In potassium hydroxide solution, at a rate of 20 ml min -1 A gas diffusion electrode loaded with In-doped copper-based catalyst was obtained by passing carbon monoxide into the gas diffusion electrode at a flow rate of -0.48 V (relative to reversible hydrogen electrode, RHE) and applying a potential of -0.48 V (relative to reversible hydrogen electrode, RHE). The reaction time was controlled to be 100 s.

[0142] 2. Assembly and performance testing of the CO2RR / CORR three-phase flow system based on In-doped copper-based catalytic electrode (i.e., Cu-In catalytic electrode);

[0143] Specifically, a gas diffusion electrode loaded with In-doped copper-based catalyst (i.e., nanomaterial of Cu-In catalyst) was used as cathode, nickel foam with electrodeposited Fe was used as anode, mercury / mercury oxide electrode was used as reference electrode, and FAB-PK-130 anion exchange membrane was used as diaphragm. 1 mol / L potassium hydroxide was passed through both sides of the diaphragm as anode and cathode electrolyte, respectively. The catalyst layer of the gas diffusion electrode faced the cathode electrolyte, and carbon monoxide was passed through the back side to assemble a CORR three-phase flow system device, and electrochemical tests were carried out.

[0144] like Fig.12 As shown in a, in a wide potential window of -0.58~-0.98 V (vs. reversible hydrogen electrode, RHE), C 2+ The selectivity is above 80%. At a potential of -0.68 V (vs. RHE), the Faradaic efficiency of n-propanol reaches 34.0%. Fig.12 b, the highest partial current density of n-propanol reaches 47.2 mA cm -2 .

[0145] It should be understood that in the above examples, the copper-based catalyst of the present invention is mainly formed by several representative regulator metal elements, but the technical solution of the present invention is not limited thereto. According to the research of the present invention, suitable 4d\5d\6d transition metal elements and main group metal elements with atomic radius larger than copper are used as regulator metal elements to replace Pb, and copper-based catalysts with improved performance can also be obtained. The material modification mechanism and preparation method of these copper-based catalysts are similar to the material modification mechanism and preparation method of the copper-based catalyst obtained by using Pb as the regulator metal element, and will not be described in detail here.

[0146] In summary, the copper-based catalyst provided in the technical solution of the present invention, in addition to carbon elements, also contains one or more regulator metal elements, and the atoms of the regulator metal elements are distributed in the copper lattice, interconnected with copper through metal bonds, and homogeneous distribution is achieved at the atomic level, and the adsorption energy of the intermediate of the carbon dioxide / carbon monoxide electrochemical reduction reaction can be adjusted through the interaction between adjacent copper atoms and the interaction between adjacent copper atoms and regulator metal element atoms, thereby improving the activity of the catalyst in the carbon dioxide / carbon monoxide electrochemical reduction reaction. And the interaction between copper atoms and regulator metal element atoms and carbon carriers respectively overcomes the phase separation problem of metal solid solution in the catalytic reaction process, promotes the atoms of the regulator metal element to be stably present in the catalyst in the form of atomic-level homogeneous mixing, and effectively improves the stability of the catalyst.

[0147] Moreover, the preparation method of the copper-based catalyst of the present invention adopts the in-situ electrochemical reduction of copper oxide and the electrochemical deposition method of the metal element ions of the regulator to overcome the problem of uneven element distribution during the preparation of multi-metal nanomaterials and catalytic electrodes, and realizes the atomic-level homogeneous mixing of multi-metals on the electrode surface. And the interaction between the carbon carrier and the metal crystal avoids the agglomeration of atoms during the reaction process and increases the stability of the catalyst. The preparation process of the copper-based catalyst is simple and low in cost, and can realize the electrochemical reduction reaction of carbon dioxide / carbon monoxide with high activity and high stability, and has broad application prospects.

[0148] In addition, the copper-based catalyst of the present invention can be used as an electrode catalyst layer to greatly improve the electrochemical properties of the electrode, increase the single product selectivity in the carbon dioxide / carbon monoxide electrochemical reduction reaction, reduce the overpotential of the carbon dioxide / carbon monoxide electrochemical reduction reaction, and increase the reaction rate, energy conversion efficiency and reactant conversion rate.

[0149] Other embodiments of the present invention further provide an electrochemical electrolysis device, which uses the copper-based catalyst of the present invention as an electrode catalyst; or, the electrochemical electrolysis device includes two electrodes, one electrode is the copper-based catalytic electrode of the present invention, which serves as the cathode of the carbon dioxide / carbon monoxide electrochemical reduction device, and the other electrode is an oxygen-producing electrode or a urea oxidation electrode. The electrochemical electrolysis device is an electrochemical electrolysis device for carbon dioxide / carbon monoxide electrochemical reduction reaction.

[0150] Embodiment 5, the electrochemical electrolysis device is a three-phase flow system electrochemical electrolysis device, and the three-phase flow system electrochemical electrolysis device uses the copper-based catalyst of the present invention as an electrode catalyst. Alternatively, the three-phase flow system electrochemical electrolysis device includes three electrodes, one electrode is the gas diffusion electrode (i.e., the copper-based catalytic electrode of the present invention) formed by the conductive gas diffusion layer and the copper-based catalyst covered on the conductive gas diffusion layer, which serves as the cathode of the carbon dioxide / carbon monoxide electrochemical reduction device, another electrode is an oxygen-producing electrode or a urea oxidation electrode, and the third electrode is a mercury / mercury oxide electrode, which serves as a reference electrode. The three-phase flow system electrochemical electrolysis device also uses an anion exchange membrane with a thickness of 25μm~250μm as a diaphragm. 0.1 mol / L~1.0 mol / L potassium bicarbonate or 0.1 mol / L~8.0mol / L potassium hydroxide are introduced on both sides of the diaphragm as anode and cathode electrolytes, respectively. The copper-based catalyst of the gas diffusion electrode faces the cathode electrolyte, and carbon dioxide or carbon monoxide is introduced on the back side of the gas diffusion electrode. Therefore, the three-phase flow system electrochemical electrolysis device can be used for carbon dioxide / carbon monoxide electrochemical reduction reactions.

[0151] Embodiment 6, the electrochemical electrolysis device is an electrochemical electrolysis device based on a polymer anion exchange membrane, and the electrochemical electrolysis device based on a polymer anion exchange membrane uses the copper-based catalyst of the present invention as an electrode catalyst. Alternatively, the electrochemical electrolysis device based on a polymer anion exchange membrane has two electrodes, one of which is a gas diffusion electrode formed by a conductive gas diffusion layer and a copper-based catalyst covered on the conductive gas diffusion layer (i.e., the copper-based catalytic electrode of the present invention), which serves as the cathode of the carbon dioxide / carbon monoxide electrochemical reduction device, and the other electrode is an oxygen-producing electrode or a urea oxidation electrode. The electrochemical electrolysis device based on the polymer anion exchange membrane also uses an anion exchange membrane with a thickness of 25μm to 250μm as a diaphragm, a titanium plate or a graphite plate engraved with a flow field as a cathode and anode end plates, pure water, 0.1mol / L to 0.5mol / L potassium bicarbonate or 0.1mol / L to 3.0mol / L potassium hydroxide as an electrolyte is introduced into the anode, and carbon dioxide or carbon monoxide is introduced into the cathode end plate as a reaction gas, so that the electrochemical electrolysis device can be used for carbon dioxide / carbon monoxide electrochemical reduction reactions.

Claims

1. A method for preparing a copper-based catalyst, characterized in that: The specific steps are: (1) preparing a first solution in which a metal salt precursor is dissolved, wherein the metal salt precursor contains at least one modifier metal element, and the modifier metal element includes at least one transition metal element or main group metal element having an atomic radius larger than that of copper; (2) adding nanometer-scale powder containing copper oxide to the first solution, and further adding a first adhesive, and stirring to produce a uniformly dispersed mixed slurry; (3) spraying or dripping the mixed slurry onto a conductive substrate placed on a hot plate and evaporating the solvent; (4) placing the conductive substrate in a corresponding electrolyte, applying a reduction potential to the conductive substrate in an environment where carbon monoxide is continuously introduced, and performing an electrochemical reduction reaction, wherein the reduced copper covers the conductive substrate to form a copper electrode, and the atoms of the regulator metal element are dissolved and deposited in situ on the copper electrode, and further bonded to the copper lattice of the copper electrode, thereby forming a regulator metal element-doped copper-based catalyst, and in the copper-based catalyst, the distribution of the regulator metal element atoms at the grain boundaries of the copper lattice is more enriched than at other positions of the copper lattice; The modifier metal element is selected from Pb, Sb, Sn, In, Au, Bi, Cd and Hg; The atomic molar ratio of the copper element in the copper-based catalyst to the metal element of the regulator is 1:Y, wherein Y is 0.005 to 0.1; The continuous introduction of carbon monoxide has a flow rate of not less than 20 ml / min; The first adhesive is selected from at least one of a Nafion solution, a polyvinylidene fluoride monomer solution and a polytetrafluoroethylene monomer solution.

2. The preparation method according to claim 1, characterized in that: The step of preparing a first solution containing a metal salt precursor comprises: (1) mixing water in a polar organic solvent to produce an organic-water mixed solvent; (2) Dissolving the metal salt precursor in the organic-water mixed solvent to produce the first solution.

3. The preparation method according to claim 1, characterized in that: The nanometer-scale powder containing copper oxide is a nanometer-scale copper oxide powder or a nanometer-scale copper oxide-carbon carrier composite material powder. The steps for preparing the nanometer-scale copper oxide-carbon carrier composite material powder include: (1) dissolving a copper salt precursor in water to produce a copper salt solution; (2) mixing an alkali solution with a copper salt solution and stirring to produce a second solution; (3) adding the carbon support to the second solution and continuously stirring to produce a uniform mixed solution; (4) transferring the uniform mixed solution to a hydrothermal reaction kettle for hydrothermal reaction to obtain a suspension containing a copper oxide-carbon carrier composite material; (5) centrifuging the suspension obtained in the hydrothermal reactor to obtain a powder sample; (6) Washing, drying and grinding the powder sample to obtain the copper oxide-carbon carrier composite material nanopowder.

4. The preparation method according to claim 3, characterized in that: The carbon carrier is selected from at least one of nano carbon powder, carbon nanotubes, graphene, reduced graphene oxide, conductive carbon black super P, conductive carbon black XC-72, conductive carbon black acetylene black and conductive carbon black BP2000.

5. The preparation method according to claim 4, characterized in that: In the copper oxide-carbon carrier composite material nano-scale powder, the molar ratio of copper element to carbon element is 1:X, wherein X is 0.2 to 1.

2.

6. A copper-based catalyst obtained by the preparation method according to any one of claims 1 to 5, which comprises a copper lattice and atoms of a regulator metal element connected to the copper lattice by metal bonds, wherein the regulator metal element comprises at least one transition metal element or main group metal element having an atomic radius larger than that of copper atoms, and the atoms of the regulator metal element are more concentrated at the grain boundaries of the copper lattice than at other positions of the copper lattice; The regulator metal element is selected from at least one of Pb, Sb, Sn, In, Au, Bi, Cd and Hg; The atomic molar ratio of the copper element in the copper-based catalyst to the regulator metal element is 1:Y, wherein Y is 0.005 to 0.

1.

7. A method for preparing a copper-based catalytic electrode, characterized in that: The specific steps are: First, a copper-based catalyst is obtained on a conductive substrate using the preparation method of the copper-based catalyst as described in any one of claims 1 to 5 as an electrode substrate; Next, the electrode substrate is washed and dried to obtain a copper-based catalytic electrode; The conductive substrate is selected from one of conductive glass, conductive metal sheet and stainless steel plate, the thickness of the conductive substrate is 0.5 mm to 2.0 mm, and the loading amount of the copper-based catalyst in the copper-based catalytic electrode is 0.2 mg / cm 2 ~5.0 mg / cm 2 .

8. A method for preparing a copper-based catalytic electrode, characterized in that: The specific steps are: First, a copper-based catalyst is obtained on a conductive substrate by using the preparation method of the copper-based catalyst as described in any one of claims 1 to 5. Then, the copper-based catalyst layer is peeled off from the conductive substrate, and the peeled copper-based catalyst is washed and then mixed with water, a second adhesive and an organic solvent to produce a catalyst slurry; Next, the catalyst slurry is sprayed or dripped onto the conductive diffusion layer and the slurry is dried to form a gas diffusion electrode covered with a copper-based catalyst layer; The second adhesive is selected from at least one of Nafion solution, polyvinylidene fluoride monomer solution, polytetrafluoroethylene monomer solution, polyethylene-tetrafluoroethylene copolymer monomer solution, and Dowex ion exchange resin solution, and the organic solvent is selected from at least one of ethanol, methanol, n-propanol, isopropanol, ethylene glycol, glycerol, acetone, and N,N-dimethylformamide; The conductive diffusion layer can be selected from hydrophobic carbon paper, thermally evaporated copper PTFE film or ion beam sputtered copper PTFE film, and the thickness of the conductive diffusion layer is 0.1 mm to 2.0 mm, and the loading amount of the copper-based catalyst in the formed gas diffusion electrode is 1 mg / cm 2 ~10mg / cm 2 .

9. A copper-based catalytic electrode obtained by the preparation method according to claim 7 or 8.

10. An electrochemical electrolysis device, characterized in that: The invention has the copper-based catalytic electrode as claimed in claim 9, and also has an oxygen producing electrode or a urea oxidation electrode.

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