Plasmon copper-based nano material, preparation method thereof and application of plasmon copper-based nano material in photoelectrocatalysis of carbon dioxide

Abstract

The invention provides a plasmon copper-based nano material, a preparation method thereof and application of the plasmon copper-based nano material in photoelectrocatalysis of carbon dioxide, nickel monatomic loaded copper phosphide nanowires are used as a plasmon catalyst, and efficient carbon dioxide conversion is realized under the condition of ultralow reaction potential and simulated sunlight irradiation. Compared with the prior art, the plasmon characteristic of the copper-based nano material is applied to the field of photoelectrocatalysis carbon dioxide reduction, efficient conversion of carbon dioxide to high-added-value hydrocarbon is achieved, and the product selectivity of ethylene and ethane reaches 90% or above; and a new way is opened up for dealing with the greenhouse effect and promoting the development of renewable energy sources.

Description

Technical Field

[0001] The present invention relates to the field of nanocatalysis technology, and in particular to a plasmonic copper-based nanomaterial, a preparation method thereof, and an application thereof in photoelectrocatalytic carbon dioxide. Background Art

[0002] In recent years, the large-scale combustion of fossil fuels has caused the continuous increase of atmospheric carbon dioxide concentration, leading to the increasingly serious environmental problems and energy shortages. It is urgent to develop carbon dioxide emission reduction and its resource utilization technology. The carbon dioxide conversion technology driven by renewable electric energy can convert carbon dioxide into high-value-added fuels and chemicals at normal temperature and pressure, which is an effective way to realize the carbon cycle, solve the global greenhouse effect and alleviate the energy crisis. However, there are still problems such as high reaction overpotential and low product selectivity in the electrocatalytic reduction of carbon dioxide. Therefore, it is urgent to develop an efficient electrocatalytic carbon dioxide reduction system to achieve high-selectivity carbon dioxide conversion at low overpotential.

[0003] At present, many advanced electrocatalysts can only achieve the efficient conversion of carbon dioxide to products such as CO, CH 4 , HCOOH, etc. of C 1 , while the selectivity of carbon dioxide reduction to C 2 products is still relatively low, and a relatively large reaction potential often needs to be applied. Compared with C 1 products (CO, CH 4 , HCOOH, CH 3 OH, etc.), multi-carbon products (C 2 H 5 OH, CH 3 COOH, C 2 H 4 , C 2 H 6 , etc.) have higher energy density and economic value. Therefore, the electrochemical reduction of carbon dioxide to multi-carbon products has a broader application prospect in industrial applications. Among many carbon dioxide catalysts, copper-based materials are the only catalysts that can achieve efficient carbon-carbon coupling and convert carbon dioxide into multi-carbon products. However, copper-based catalysts still face the problems of slow carbon-carbon coupling rate and low selectivity of multi-carbon products. This is mainly because the dimerization energy barrier of *CO is too high, resulting in the reaction path tending to generate C 1 products. Especially at low overpotential, the slow *CO generation rate will further limit the dimerization of *CO. Therefore, improving the carbon-carbon coupling reaction kinetics of copper-based catalysts is the key to achieving high-selectivity carbon dioxide conversion to multi-carbon products at low overpotential. Summary of the Invention

[0004] The object of the present invention is to solve the above problems and provide a plasmonic copper-based nanomaterial, its preparation method and application in photoelectrocatalytic carbon dioxide. The plasmonic electrons generated by the copper nanostructure under light illumination are used to accelerate the activation of carbon dioxide into *CO, and the doped phosphorus atoms are used to induce the generation of local Cu + to stabilize *CO. In addition, the introduced nickel atoms simultaneously promote the hydrogenation of *CO to generate *CHO, ultimately improving the kinetics of the carbon-carbon coupling reaction, thereby achieving highly selective photoelectrocatalytic reduction of carbon dioxide to ethylene and ethanol at a low overpotential.

[0005] The object of the present invention is achieved by the following technical solutions:

[0006] The first object of the present invention is to provide a plasmonic copper-based nanomaterial, which is a nickel single-atom loaded copper phosphide nanowire; the plasmonic copper-based nanomaterial is used as a plasmonic catalyst to achieve highly selective carbon dioxide conversion under ultra-low reaction potential conditions and simulated sunlight irradiation.

[0007] Preferably, the nickel single-atom loaded copper phosphide nanowire has a linear morphology, and the diameter of the nickel single-atom loaded copper phosphide nanowire is 50-200 nm.

[0008] More preferably, the diameter of the nickel single-atom loaded copper phosphide nanowire is 80-140 nm.

[0009] Preferably, in the plasmonic copper-based nanomaterial, nickel is dispersed in the form of single atoms on the copper phosphide nanowire, and the mass percentage of nickel to copper is 0.1%-10%, and the mass percentage of phosphorus to copper is 0.01%-1% (to modify the copper surface, the phosphorus content is relatively small, and this ratio is based on the actual P content measured by ICP-OES).

[0010] More preferably, the mass percentage of nickel to copper on the surface of the nickel single-atom loaded copper phosphide nanowire is 0.5%-3%, and the mass percentage of phosphorus to copper is 0.1%-0.6%.

[0011] The second object of the present invention is to provide a preparation method of a plasmonic copper-based nanomaterial, and the preparation method includes the following steps:

[0012] 1) Oxidize metallic copper in an oxidant solution to obtain a precursor, and then heat-treat the precursor in a muffle furnace to obtain copper oxide nanowires;

[0013] 2) Drop the nickel salt solution onto the surface of the copper oxide nanowires obtained in step 1), place the copper oxide nanowires and hypophosphite in a tube furnace, and perform heat treatment in an inert atmosphere. Finally, electrochemically reduce the heat-treated sample to obtain copper phosphide nanowires loaded with nickel single atoms, namely the plasmonic copper-based nanomaterials.

[0014] Further, the metallic copper in step 1) includes but is not limited to one of copper foam, copper sheet, copper mesh, and copper block.

[0015] More preferably, the metallic copper in step 1) is copper foam.

[0016] Further, the oxidant solution in step 1) includes sodium hydroxide, an oxidant, and a solvent; wherein the solvent is deionized water.

[0017] Further, in the oxidant solution, the concentration of sodium hydroxide is 1 - 4 M, and the concentration of the oxidant is 0.05 - 1 M.

[0018] Further, the oxidant in step 1) includes but is not limited to one or more of sodium persulfate, potassium persulfate, ammonium persulfate, and potassium monopersulfate.

[0019] More preferably, the oxidant in step 1) is ammonium persulfate.

[0020] Further, the oxidation reaction time in step 1) is 10 - 60 min.

[0021] Further, the oxidation reaction time in step 1) is 20 - 40 min.

[0022] Further, the heat treatment temperature in step 1) is 150 - 400 °C, and the heat treatment time is 1 - 5 h.

[0023] More preferably, the heat treatment temperature in step 1) is 250 - 400 °C, and the time is 2 - 4 h.

[0024] Further, the nickel salt solution in step 2) includes a nickel salt and a solvent; wherein the solvent is ethanol.

[0025] Further, the concentration of the nickel salt in step 2) is 0.01 - 0.03 M.

[0026] Further, the nickel salt in step 2) includes but is not limited to one or more of nickel nitrate hexahydrate, nickel chloride hexahydrate, nickel sulfate hexahydrate, and nickel acetate tetrahydrate.

[0027] More preferably, the nickel salt in step 2) is nickel chloride hexahydrate; the hypophosphite in step (2) is sodium hypophosphite.

[0028] Further preferably, the inert atmosphere described in step 2) includes, but is not limited to, one of high-purity argon and high-purity nitrogen, and the purity of high-purity argon and high-purity nitrogen is greater than 99.999%.

[0029] Further, the heat treatment temperature described in step 2) is 250-500 °C, and the time is 0.5-4 h.

[0030] Further preferably, the heat treatment temperature described in step 2) is 250-350 °C, and the time is 1-3 h.

[0031] Further, the electrochemical reduction conditions described in step 2) are: reduction for 20-60 min at an applied potential of -0.4 to -1.2 V (vs. RHE).

[0032] Further, the electrochemical reduction conditions described in step 2) are: reduction for 30 min at an applied potential of -0.8 V (vs. RHE).

[0033] The third object of the present invention is to provide an application of a plasmonic copper-based nanomaterial in photocatalytic reduction of carbon dioxide. Using copper phosphide nanowires loaded with nickel single atoms (plasmonic copper-based nanomaterials) as plasmonic catalysts, highly efficient carbon dioxide conversion is achieved under ultra-low reaction potential conditions and simulated solar light irradiation.

[0034] Further, the application method includes the following steps:

[0035] Using the plasmonic copper-based nanomaterial as the working electrode, a silver-silver chloride electrode as the reference electrode, a platinum sheet as the counter electrode, and a potassium bicarbonate solution saturated with carbon dioxide as the electrolyte, under an applied potential of -0.2 to -0.4 V (vs. RHE) and simulated solar light irradiation with an intensity of 100-1000 mW / cm 2 photocatalytic reaction is carried out to achieve highly selective carbon dioxide conversion.

[0036] Further, the plasmonic copper-based nanomaterial is used as a plasmonic catalyst to photocatalytically reduce carbon dioxide into high-value hydrocarbons.

[0037] Further, the high-value hydrocarbons include ethylene and ethane.

[0038] Further preferably, the concentration of the potassium bicarbonate solution is 0.5 M.

[0039] Further preferably, the intensity of the simulated solar light is 100-1000 mW / cm 2 .

[0040] Further preferably, the intensity of the simulated solar light is 500-800 mW / cm2 。

[0041] Further, the ultra-low reaction potential condition is an applied potential of -0.2 to -0.4 V (vs. RHE);

[0042] More preferably, the ultra-low reaction potential condition is -0.2 V (vs. RHE).

[0043] Further, the high-selectivity carbon dioxide conversion refers to: the selectivity of carbon dioxide conversion is 90% or more.

[0044] More preferably, the selectivity of carbon dioxide conversion reaches 95% or more.

[0045] Compared with the prior art, the beneficial effects of the present invention are embodied in the following aspects:

[0046] (1) The plasmonic copper-based nanomaterials provided by the present invention have a simple preparation process, are easy to control, have low-cost preparation raw materials, are environmentally friendly, and will not cause secondary pollution.

[0047] (2) For the plasmonic copper-based nanomaterials provided by the present invention, their preparation method and application in photoelectrocatalytic carbon dioxide, the selectivity of ethylene and ethane in the product is as high as more than 90%, and the stability is relatively good.

[0048] (3) For the plasmonic copper-based nanomaterials provided by the present invention, their preparation method and application in photoelectrocatalytic carbon dioxide, the plasmonic hot electrons generated by the copper nanostructure under light illumination accelerate the activation of carbon dioxide into *CO, and the doped phosphorus atoms induce the generation of local Cu + to stabilize *CO. In addition, the introduced nickel atoms simultaneously promote the hydrogenation of *CO to generate *CHO, ultimately reducing the carbon-carbon coupling reaction energy barrier, improving the selectivity of photoelectrocatalytic carbon dioxide reduction to high-value hydrocarbons, and providing a new way to alleviate the global greenhouse effect and promote the development of renewable energy. Description of the Drawings

[0049] Figure 1 XRD patterns of the copper nanowires and nickel single-atom loaded copper phosphide nanowires prepared in Example 1;

[0050] Figure 2 Ultraviolet absorption spectra of the copper nanowires and nickel single-atom loaded copper phosphide nanowires prepared in Example 1;

[0051] Figure 3 TEM and HR-TEM images of the nickel single-atom loaded copper phosphide nanowires prepared in Example 1;

[0052] Figure 4TEM and HR-TEM images of the copper nanowires prepared in Example 1;

[0053] Figure 5 Product distribution map of the photo-electrocatalytic reduction of carbon dioxide by nickel single-atom loaded copper phosphide nanowires prepared in Example 2;

[0054] Figure 6 Product distribution map of the photo-electrocatalytic reduction of carbon dioxide by the copper nanowires prepared in Comparative Example 1.

[0055] Figure 7 Product distribution map of the photo-electrocatalytic reduction of carbon dioxide by the copper phosphide nanowires prepared in Comparative Example 2.

[0056] Figure 8 Product distribution map of the photo-electrocatalytic reduction of carbon dioxide by nickel single-atom loaded copper nanowires prepared in Comparative Example 3.

[0057] Figure 9 Bar chart of the product selectivity of ethylene and ethane in the photo-electrocatalytic reduction of carbon dioxide by nickel single-atom loaded copper phosphide nanowires prepared in Example 2. Detailed Description of the Invention

[0058] The present invention will be described in detail below in conjunction with specific embodiments, but it is by no means a limitation of the present invention. The preparation means, materials, structures or composition ratios and other features not clearly described in the present technical solution are regarded as common technical features disclosed in the prior art.

[0059] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0060] Example 1:

[0061] This example provides a preparation method of nickel single-atom loaded copper phosphide nanowires (plasmonic copper-based nanomaterials), and the preparation method includes the following steps:

[0062] (1) Cut a commercial foam copper sheet into a uniform electrode sheet of 2×2 cm (with a mass of about 2.3 g), ultrasonically clean it with deionized water and ethanol for 10 min respectively, and then place it in 100 mL of deionized water dissolved with 10 g of sodium hydroxide and 2.3 g of ammonium persulfate solids. After soaking for 40 min, take it out to obtain a precursor.

[0063] (2) Place the precursor obtained in the above process in a muffle furnace, heat-treat it at 300 °C for 2 h, and set the heating rate to 5 °C / min to obtain copper oxide nanowires.

[0064] (3) On each of the two surfaces of the copper oxide nanowires, 1 mL of a nickel chloride hexahydrate ethanol solution with a concentration of 0.017 M was drop-coated, and then it was placed in a tube furnace together with a porcelain boat containing 2 g of sodium hypophosphite solid. Among them, sodium hypophosphite was placed in the upwind position, and the copper oxide nanowires were placed in the downwind position. Under a high-purity argon atmosphere, it was heat-treated at 300 °C for 2 h, and the heating rate was set at 2 °C / min. Finally, the electrode obtained after the reaction was completed was reduced at an external potential of -0.8 V (vs. RHE) for 30 min to prepare copper phosphide nanowires loaded with nickel single atoms (plasmonic copper-based nanomaterials).

[0065] Preparation of the control material copper nanowires:

[0066] The copper oxide nanowire electrode prepared by the above process was reduced at an external potential of -0.8 V (vs. RHE) for 30 min to obtain copper nanowires.

[0067] Figure 1 XRD patterns of copper nanowires and copper phosphide nanowires loaded with nickel single atoms: It can be seen from the XRD patterns that the main component of the synthesized material is zero-valent copper.

[0068] Figure 2 UV absorption spectra of copper nanowires and copper phosphide nanowires loaded with nickel single atoms: It can be seen from the UV absorption spectra that both copper nanowires and copper phosphide nanowires loaded with nickel single atoms exhibit plasmonic characteristic absorption near a wavelength of 550 nm, that is, the copper phosphide nanowires loaded with nickel single atoms are plasmonic copper-based nanomaterials.

[0069] Figure 3 TEM and HR-TEM images of copper phosphide nanowires loaded with nickel single atoms: It can be seen from the TEM image that the diameter of the linear structure of the synthesized copper phosphide nanowires loaded with nickel single atoms is about 130 nm; it can be seen from the HR-TEM image that the copper phosphide nanowires loaded with nickel single atoms are mainly exposed with the Cu(111) crystal plane, and the interplanar spacing is 0.208 nm.

[0070] Figure 4 TEM and HR-TEM images of copper nanowires: It can be seen from the TEM image that the diameter of the linear structure of the synthesized copper nanowires is about 120 nm; it can be seen from the HR-TEM image that the copper nanowires are mainly exposed with the Cu(111) crystal plane, and the interplanar spacing is 0.208 nm.

[0071] Example 2

[0072] This example provides an application of copper phosphide nanowires loaded with nickel single atoms (plasmonic copper-based nanomaterials) in the photoelectrocatalytic carbon dioxide reduction reaction:

[0073] The photocatalytic carbon dioxide reduction reaction was carried out in a flow photoelectrochemical cell with a three-electrode system. The electrolytic cell was separated into the anode and cathode by an anion exchange membrane. The copper phosphide nanowires loaded with nickel single atoms obtained in Example 1 were used as the working electrode, silver-silver chloride as the reference electrode, and a platinum sheet as the counter electrode. The electrolyte was a 0.5 M potassium bicarbonate solution saturated with carbon dioxide. Under simulated sunlight irradiation with an intensity of 500 mW / cm 2 a constant voltage carbon dioxide reduction reaction was carried out, and carbon dioxide gas was continuously introduced during the reaction. The experimental results are as Figure 5 shown.

[0074] In Example 2, the total Faradaic efficiency of the copper phosphide nanowires loaded with nickel single atoms for electrocatalytic reduction of carbon dioxide to ethylene and ethane was 91% at -0.2 V (vs. RHE), and the product selectivity for ethylene and ethane was 96%.

[0075] Comparative Example 1

[0076] This comparative example provides an application of copper nanowires in the photocatalytic carbon dioxide reduction reaction:

[0077] The photocatalytic carbon dioxide reduction reaction was carried out in a flow photoelectrochemical cell with a three-electrode system. The electrolytic cell was separated into the anode and cathode by an anion exchange membrane. The control material copper nanowires obtained in Example 1 were used as the working electrode, silver-silver chloride as the reference electrode, and a platinum sheet as the counter electrode. The electrolyte was a 0.5 M potassium bicarbonate solution saturated with carbon dioxide. Under simulated sunlight irradiation with an intensity of 500 mW / cm 2 a constant voltage carbon dioxide reduction reaction was carried out, and carbon dioxide gas was continuously introduced during the reaction. The experimental results are as Figure 6 shown.

[0078] In Comparative Example 1, the Faradaic efficiency of the copper nanowires for electrocatalytic reduction of carbon dioxide to ethylene was 17% at -0.4 V (vs. RHE), and no ethane was detected.

[0079] Comparative Example 2

[0080] This comparative example provides a kind of copper phosphide nanowires, and the preparation method comprises the following steps:

[0081] (1) Cut a commercial copper foam sheet into a uniform electrode sheet of 2×2 cm (with a mass of about 2.3 g), and ultrasonically clean it with deionized water and ethanol for 10 min respectively. Then place it in 100 mL of deionized water dissolved with 10 g of sodium hydroxide and 2.3 g of ammonium persulfate solids, soak it for 40 min and then take it out to obtain a precursor.

[0082] (2) Place the precursor obtained in the above process in a muffle furnace, heat-treat it at 300 °C for 2 h, and set the heating rate to 5 °C / min to obtain copper oxide nanowires.

[0083] (3) Place the copper oxide nanowires and a porcelain boat containing 2 g of sodium hypophosphite solid in a tubular furnace, with the sodium hypophosphite placed upwind and the copper oxide nanowires placed downwind. Under an atmosphere of high-purity argon, heat-treat at 300 °C for 2 h, set the heating rate to 2 °C / min, and finally reduce the electrode obtained after the reaction for 20 - 60 min at an applied potential of -0.4 to -1.2 V (vs. RHE), thus obtaining copper phosphide nanowires.

[0084] This comparative example provides an application of copper phosphide nanowires in the photoelectrocatalytic carbon dioxide reduction reaction. The specific process is the same as that of Comparative Example 1, except that the working electrode is the copper phosphide nanowires obtained in this comparative example. The experimental results are as Figure 7 shown. The Faraday efficiency for the electrocatalytic reduction of carbon dioxide to ethylene at -0.4 V (vs. RHE) is 26%, and no ethane is detected.

[0085] Comparative Example 3

[0086] This comparative example provides copper nanowires loaded with nickel single atoms. The preparation method includes the following steps:

[0087] (1) Cut a commercial copper foam sheet into a uniform electrode sheet of 2 × 2 cm (with a mass of about 2.3 g), ultrasonically clean it with deionized water and ethanol for 10 min respectively, and then place it in 100 mL of deionized water dissolved with 10 g of sodium hydroxide and 2.3 g of ammonium persulfate solid. After soaking for 40 min, take it out to obtain a precursor.

[0088] (2) Place the precursor obtained in the above process in a muffle furnace, heat-treat at 300 °C for 2 h, set the heating rate to 5 °C / min, to obtain copper oxide nanowires.

[0089] (3) Drop 1 mL of nickel chloride hexahydrate ethanol solution with a concentration of 0.017 M on each of the two surfaces of the copper oxide nanowires, and then place it in a tubular furnace. Under an atmosphere of 5% hydrogen-argon mixture (5% hydrogen, 95% argon), heat-treat at 300 °C for 2 h, set the heating rate to 2 °C / min, and finally reduce the electrode obtained after the reaction for 20 - 60 min at an applied potential of -0.4 to -1.2 V (vs. RHE), thus obtaining copper nanowires loaded with nickel single atoms.

[0090] This comparative example provides an application of copper nanowires loaded with nickel single atoms in the photoelectrocatalytic carbon dioxide reduction reaction. The specific process is the same as that of Comparative Example 1, except that the working electrode is the copper nanowires loaded with nickel single atoms obtained in this comparative example. The experimental results are as Figure 8 shown. The total Faraday efficiency for the electrocatalytic reduction of carbon dioxide to ethylene and ethane at -0.4 V (vs. RHE) is 41%.

[0091] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those who are familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A plasmonic copper-based nanomaterial, characterized in that: The plasmonic copper-based nanomaterial is a copper phosphide nanowire loaded with nickel single atoms; The plasmonic copper-based nanomaterial is used as a plasmonic catalyst to achieve highly selective carbon dioxide conversion under ultra-low reaction potential conditions and simulated solar light irradiation.

2. The plasmonic copper-based nanomaterial according to claim 1, characterized in that: The copper phosphide nanowires loaded with nickel single atoms are linear in shape, and the diameter of the copper phosphide nanowires loaded with nickel single atoms is 50-200 nm.

3. The plasmonic copper-based nanomaterial according to claim 1, characterized in that: In the plasmon copper-based nanomaterial, nickel is dispersed on the copper phosphide nanowire in the form of single atoms, the mass percentage of nickel to copper is 0.1% to 10%, and the mass percentage of phosphorus to copper is 0.01% to 1%.

4. A method for preparing a plasmonic copper-based nanomaterial as claimed in any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: 1) placing metallic copper in an oxidant solution for oxidation reaction to obtain a precursor, and then placing the precursor in a muffle furnace for heat treatment to obtain copper oxide nanowires; 2) applying a nickel salt solution dropwise onto the surface of the copper oxide nanowires obtained in step 1), placing the copper oxide nanowires and hypophosphite in a tube furnace, and subjecting them to heat treatment in an inert atmosphere, and finally electrochemically reducing the heat-treated sample to obtain copper phosphide nanowires loaded with nickel single atoms, i.e., the plasmonic copper-based nanomaterial.

5. The method for preparing plasmonic copper-based nanomaterials according to claim 4, characterized in that: The metal copper in step 1) includes one of foam copper, copper sheet, copper mesh and copper block; The oxidant in step 1) includes one or more of sodium persulfate, potassium persulfate, ammonium persulfate and potassium peroxymonosulfate.

6. The method for preparing plasmonic copper-based nanomaterials according to claim 4, characterized in that: The oxidation reaction time in step 1) is 10 to 60 minutes; The heat treatment temperature in step 1) is 150-400° C., and the heat treatment time is 1-5 hours.

7. The method for preparing plasmonic copper-based nanomaterials according to claim 4, characterized in that: The nickel salt in step 2) includes one or more of nickel nitrate hexahydrate, nickel chloride hexahydrate, nickel sulfate hexahydrate and nickel acetate tetrahydrate; The phosphate in step 2) includes one or more of sodium hypophosphite, potassium hypophosphite and magnesium hypophosphite.

8. The method for preparing plasmonic copper-based nanomaterials according to claim 4, characterized in that: The inert gas in step 2) includes one of high-purity argon and high-purity nitrogen; The heat treatment temperature in step 2) is 250-500° C. and the time is 0.5-4 h.

9. Use of a plasmonic copper-based nanomaterial according to any one of claims 1 to 3 in photoelectrocatalytic carbon dioxide generation, characterized in that: The steps include: Using plasmonic copper-based nanomaterials as working electrodes, silver-silver chloride electrodes as reference electrodes, platinum sheets as counter electrodes, and carbon dioxide-saturated potassium bicarbonate solution as electrolytes, photoelectrocatalytic reactions were carried out under ultra-low reaction potential conditions and simulated solar irradiation to achieve highly selective carbon dioxide conversion.

10. The use according to claim 9, characterized in that: The selectivity of carbon dioxide conversion is 90% to 96%; The ultra-low reaction potential condition is -0.2 to -0.4 V vs. RHE applied potential; The intensity of the simulated solar radiation is 100-1000 mW / cm 2 .

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