Preparation method and application of CuxSny bimetallic catalyst

Abstract

The invention belongs to the technical field of carbon dioxide recycling, and discloses a preparation method and application of a CuxSny bimetallic catalyst. According to the method, co-deposition of metal ions and electrode surface reconstruction are realized on a copper substrate in an aged CuSn precursor solution by utilizing a square wave voltammetry. The precursor solution contains a copper salt, a tin salt, potassium sodium tartrate tetrahydrate and a nitrogen-containing compound. Wherein the potassium sodium tartrate tetrahydrate and the nitrogen-containing compound are used as stabilizers to promote uniform co-deposition of metals; a square wave voltammetry is adopted for electrodeposition, and accurate regulation and control are achieved through the potential waveform of stepped linear scanning and high-frequency square wave pulse; complex-state ions are driven by forward pulse to be synchronously separated out in proportion; performing reverse pulse etching on the unstable crystal nucleus and the large particles to form uniform nanoparticles; and the high-frequency characteristic inhibits concentration polarization and stabilizes the load capacity. The morphology-controllable catalyst prepared by the method has the advantages that the selectivity of formic acid at normal temperature and normal pressure is increased to about 89%, and the method is an ideal catalyst preparation scheme.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide resource utilization, and the present invention relates to a Cu x Sn y Preparation method and application of bimetallic catalyst. Background Art

[0002] The acceleration of the global industrialization process and the surge in energy demand have driven the consumption of fossil fuels such as oil and natural gas to continue to rise. According to statistics from the International Energy Agency (IEA), global fossil fuel-related CO2 emissions reached a record 37.4 billion tons in 2023, exacerbating the global warming and climate change crisis. To meet this severe challenge, a variety of carbon reduction strategies have been proposed and implemented. In addition to emission reduction at the source, carbon capture and utilization (CCUS) is a key path to regulating atmospheric CO2 concentrations. Among them, the electrocatalytic carbon dioxide reduction reaction (ERECO2) has become a very promising environmentally friendly conversion technology due to its core advantages such as room temperature and pressure operation, high selectivity, and the direct use of renewable energy electricity. In the diversified product system of ERECO2, formic acid (HCOOH) is regarded as one of the target products with the most commercial potential due to its high selectivity generation efficiency, low energy consumption conversion path and mature application scenarios.

[0003] To date, a variety of electrode materials have been used for the electrochemical reduction of CO2 to formic acid. Catalysts containing two metal elements, Cu and Sn, exhibit unique advantages in the electrochemical reduction of carbon dioxide (ECO2RR) to produce formic acid due to the synergistic effect of copper's high conductivity and tin's affinity for oxygen. For example, Chunyue Shen et al. synthesized a CuO / SnO2 heterojunction catalyst using a combination of hydrothermal reaction and high-temperature annealing. The large number of interfaces in the CuO / SnO2 heterojunction accelerated electron transport, promoted the formation of active intermediates, and improved the efficiency of C1 product formation, with the Faradaic efficiency maintained above 80% (Chemical Physics Letters, 2023, 818, 140438.). However, existing heterojunction catalysts have problems such as high reaction potential, unstable intermediate adsorption, complex preparation, and difficult composition control, which are not conducive to large-scale industrial production and application. Therefore, it is necessary to develop an electrocatalyst that uses a controllable and efficient method to solve the above problems.

[0004] To this end, we provide a simple and efficient preparation method of Cu, Sn bimetallic catalyst for electroreduction of carbon dioxide and its application to make up for the above shortcomings. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a Cu x Sn yPreparation method of bimetallic catalyst and its application. A preparation method of Cu, Sn bimetallic catalyst for electroreduction of carbon dioxide prepared by in-situ square wave voltammetry treatment and its application. Based on low carbon and environmental protection, the present invention uses a highly efficient and controllable square wave voltammetry treatment method to reconstruct the surface of the copper mesh copper substrate, expand the solid, liquid and gas three-phase reaction interface, and uniformly deposit Cu. x Sn y Bimetallic nanoparticles. The formation of these structures can effectively adsorb carbon dioxide, reduce the energy barrier for the formation of *OCHO, a key intermediate, thereby promoting the production of formic acid and improving the selectivity for a single product.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0007] A Cu x Sn y Bimetallic catalyst, Cu supported on the surface of copper substrate x Sn y Bimetallic nanoparticles as catalysts, in which Cu x Sn y The bimetallic nanoparticles are recorded as bimetallic layers, the copper substrate is the base layer, and the Cu x Sn y The content of bimetallic nanoparticles is 5-30 mg / cm 2 , where x:y = 1:4 to 4:1; in the bimetallic layer, the molar content of Cu is 20 to 80%, and the molar content of Sn is 80 to 20%; the surface of the copper substrate is uniformly electrodeposited with Cu x Sn y Bimetallic nanoparticles, particle size is 10 to 80 nm.

[0008] The present invention also claims the above-mentioned Cu x Sn y The preparation method of the bimetallic catalyst specifically comprises the following steps:

[0009] S1: prepare CuSn precursor solution and perform aging treatment;

[0010] A solution containing a copper salt, a tin salt, and a stabilizer in a certain proportion is prepared and aged under stirring to obtain a CuSn precursor solution;

[0011] S2: Processing of copper substrate;

[0012] Treat the copper substrate by using 10 mL of 2-10 M hydrochloric acid, ethanol, and ultrapure water in an ultrasonic cleaner for 20 minutes to clean it.

[0013] S3: In situ electrodeposition on copper substrate using square wave voltammetry;

[0014] The copper substrate treated in S2 is placed in the CuSn precursor solution prepared in S1 for square wave voltammetry electrodeposition.

[0015] S4: cleaning;

[0016] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain Cu x Sn y Bimetallic catalysts.

[0017] Furthermore, in step S1, the copper salt is selected from one or more of copper chloride, copper sulfate, and copper nitrate; the tin salt is selected from one or more of stannous chloride and stannous sulfate; the molar ratio of the copper salt to the tin salt is 1:4 to 4:1, preferably 2:3 to 3:2; the copper salt is preferably copper chloride; and the tin salt is preferably stannous chloride.

[0018] Furthermore, in step S1, the stabilizer is a mixture of potassium sodium tartrate tetrahydrate and a nitrogen-containing compound; the nitrogen-containing compound is selected from any one or more of urea, ammonia, and ethylenediamine; the concentration of potassium sodium tartrate tetrahydrate is 1 to 4 mM, preferably 2 to 3 mM; the concentration of the nitrogen-containing compound is 4 to 1 mM, preferably 3 to 2 mM; and the molar ratio of potassium sodium tartrate hydrate to the nitrogen-containing compound is 2:3 to 3:2. The stabilizer is preferably a mixture of potassium sodium tartrate tetrahydrate and urea.

[0019] Furthermore, in step S1, the total molar concentration of the copper salt and the tin salt is equal to the total molar concentration of the stabilizer.

[0020] Furthermore, in step S1, aging is performed under stirring at room temperature, with a stirring speed of 400 to 600 rpm, preferably 500 rpm, and an aging time of 10 to 18 hours, preferably 12 to 14 hours.

[0021] Furthermore, in step S2, the copper substrate is selected from any one of copper foam, copper mesh, copper plate, and copper foil. The copper substrate is preferably a copper mesh. The mesh size of the copper mesh substrate is 20 to 400, preferably 100 to 200. The wire diameter of the copper mesh is 0.04 to 0.13 mm, preferably 0.05 to 0.08 mm.

[0022] Furthermore, in step S3, the specific parameters of the square wave voltammetry electrodeposition are set as follows: the starting potential is set to +0.1V to +0.8V, preferably +0.2V to +0.6V; the ending potential is set to -1.0V to -1.8V, preferably -1.2V to -1.6V; the pulse height is 10mV to 50mV, preferably in the range of 20mV to 40mV; the step height is 5mV to 35mV, preferably in the range of 10mV to 30mV; and the frequency is set to 5Hz to 35Hz, preferably in the range of 10Hz to 30Hz. The ending potential is always lower than the starting potential.

[0023] The present invention further claims the use of the catalyst prepared by the above-mentioned preparation method in the electrochemical reduction of carbon dioxide, wherein the CuxSny bimetallic catalyst serves as the cathode. The electrolyte for the electrochemical reduction of carbon dioxide is KHCO3; the electrolyte concentration is 0.1M to 1M, preferably 0.1M to 0.5M.

[0024] In specific applications, the prepared Cu x Sn y The bimetallic catalyst was washed with 100 ml of deionized water and dried with nitrogen, and then used as a working electrode for the electroreduction of carbon dioxide. An Ag / AgCl electrode was selected as a reference electrode, and a 1 cm×1 cm platinum sheet was selected as a counter electrode. An H-type electrolytic cell was used for the electroreduction of carbon dioxide. The cathode chamber and the anode chamber were separated by a proton exchange membrane. The two chambers were filled with 40 mL of 0.5 M KHCO3 respectively. The working electrode and the reference electrode were fixed in the cathode chamber, and the counter electrode was fixed in the anode chamber. 99.999% high-purity carbon dioxide was introduced into the cathode chamber at a flow rate of 35 sccm. The reaction began after carbon dioxide saturation for 30 minutes. A voltage of -1.9 V was applied to carry out the electrochemical reduction of carbon dioxide to maximize the conversion rate of formic acid.

[0025] The beneficial effects of the present invention compared with the prior art are:

[0026] Compared with the common direct electrodeposition of Cu and Sn metals, the electrolyte solution prepared in the present invention further adds two organic substances as stabilizers, namely potassium sodium tartrate tetrahydrate and nitrogen-containing compounds. 2+ and Sn 2+ The complexation reaction occurs, changes the existence form of metal ions in the electrolyte, regulates the reduction potential of metal ions, ensures that the precipitation potential of the two ions is similar, thereby promoting the uniform co-deposition of Cu and Sn, and helping to form Cu with a specific structure and composition. x Sn yBimetallic catalysts prevent isolated or uneven deposition of metal ions. Furthermore, the addition of nitrogen-containing compounds regulates the solution's pH, acting as a buffer to maintain a stable pH balance and prevent local pH variations during electrodeposition from affecting the metal ion deposition rate and catalyst structure. Furthermore, a stable pH environment helps ensure the stability of potassium sodium tartrate tetrahydrate as a complexing agent, allowing it to better complex metal ions. The combined action of these two substances promotes the uniform co-deposition of Cu and Sn.

[0027] The present invention adopts efficient and sensitive square wave voltammetry (SWV) technology to deposit Cu x Sn y Bimetallic catalyst. The potential waveform of square wave voltammetry (SWV) is "step linear sweep + high-frequency square wave pulse". When square wave voltammetry is used for electrodeposition, high-frequency pulses are applied at a certain frequency, and the potential is linearly swept from the positive range to the negative range. In this process, high-frequency pulses achieve Cu reduction through a periodic "cathode reduction-anodic dissolution" alternating mechanism. 2+ With Sn 2+ Precise co-deposition control: During the forward pulse phase, a strong reduction driving force promotes the synchronous precipitation of complex metal ions. Leveraging the synergistic effect of potassium sodium tartrate tetrahydrate and nitrogen-containing compounds, the reduction potential difference between Cu and Sn is reduced, ensuring their co-deposition in a specific ratio. During the reverse pulse phase, unstable surface nuclei and large particles are selectively etched through a specific step height, ultimately forming uniformly dispersed nanoparticles through a "deposition-screening" cycle. Simultaneously, high-frequency characteristics accelerate ion diffusion and replenishment on the electrode surface, effectively suppressing localized deposition imbalances caused by concentration polarization and controlling the amount of catalytic layer loaded on the copper substrate. The resulting bimetallic interface reduces the energy barrier for the formation of *OCHO intermediates, providing highly efficient active sites for the electroreduction of CO2 to formic acid.

[0028] The stabilizer is used to form a stronger chemical bond with the metal ion to build a stable complex and achieve uniform dispersion in the system, thereby improving the dispersion of the catalyst. At the same time, the Cu x Sn y Bimetallic nanoparticles. This method is not only simple and feasible, but also allows for the rapid and efficient preparation of morphology-controllable electrodes at room temperature and pressure. The catalyst prepared using this method not only increases the selectivity for formic acid to approximately 89%, but also inhibits the occurrence of the hydrogen evolution side reaction, reducing the selectivity for hydrogen to approximately 11%, making it an ideal and feasible solution for the preparation of electrochemical catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is a distribution diagram of reduction products of the Cu2Sn3 bimetallic catalyst for electrochemical reduction of carbon dioxide in carbon dioxide-saturated 0.5M KHCO3 according to Example 1 of the present invention;

[0030] Figure 2 Energy dispersive X-ray spectroscopy (EDS) characterization of the Cu2Sn3 bimetallic catalyst for electrochemical reduction of carbon dioxide according to Example 1 of the present invention;

[0031] Figure 3 Energy dispersive X-ray spectroscopy (EDS) characterization of the Cu2Sn3 bimetallic catalyst for electrochemical reduction of carbon dioxide according to Example 1 of the present invention;

[0032] Figure 4 Scanning electron microscopy (SEM) characterization of the Cu2Sn3 bimetallic catalyst for electroreduction of carbon dioxide according to Example 1 of the present invention;

[0033] Figure 5 FIG4 is a scanning electron microscope (SEM) characterization of the Cu2Sn3 bimetallic catalyst for electroreduction of carbon dioxide according to Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The present invention is described in detail below by specific examples, but the scope of protection of the present invention is not limited. Unless otherwise specified, the experimental methods adopted in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0035] The present invention relates to a method for in-situ preparation of Cu2O3 for electroreduction of carbon dioxide by using square wave voltammetry. x Sn y A preparation method and application of a bimetallic catalyst. This preparation method improves the selectivity of the catalyst for the electroreduction of carbon dioxide to formic acid. The preparation method utilizes square-wave voltammetry to achieve co-deposition of metal ions and electrode surface reconstruction on a copper substrate in an aged CuSn precursor solution. The precursor solution contains a copper salt, a tin salt, potassium sodium tartrate tetrahydrate, and a nitrogen-containing compound. The potassium sodium tartrate tetrahydrate and the nitrogen-containing compound act as stabilizers, promoting uniform co-deposition of the two metals. Electrodeposition is achieved using square-wave voltammetry, leveraging its "linear sweep + high-frequency square wave pulse" potential waveform for precise control. The forward pulse drives the proportional and synchronous precipitation of complex ions; the reverse pulse etches unstable nuclei and large particles, forming uniform nanoparticles. The high-frequency characteristic suppresses concentration polarization and stabilizes the loading. This method produces a morphologically controllable catalyst with an increased selectivity for formic acid of approximately 89% at room temperature and pressure, making it an ideal catalyst preparation method.

[0036] The steps of the catalyst preparation method include the following:

[0037] A Cux Sn y Bimetallic catalyst, Cu supported on the surface of copper substrate x Sn y Bimetallic nanoparticles, Cu x Sn y Bimetallic nanoparticles act as a bimetallic layer, and Cu x Sn y (n Cu :n Sn =x:y=1:4-4:1) The content of bimetallic nanoparticles is 5-30 mg / cm 2 , wherein the molar content of Cu is 20-80%, and the molar content of Sn is 80-20%; the surface of the copper substrate is uniformly electrodeposited with Cu x Sn y Bimetallic nanoparticles, particle size is 10 to 80 nm.

[0038] The present invention also seeks to protect a method for preparing the above-mentioned CuxSny bimetallic catalyst, which specifically comprises the following steps:

[0039] S1: Prepare CuSn precursor solution and perform aging treatment

[0040] A solution containing a copper salt, a tin salt, and a stabilizer in a certain proportion is prepared and aged under stirring to obtain a CuSn precursor solution;

[0041] Furthermore, in step S1, the copper salt is selected from one or more of copper chloride, copper sulfate, and copper nitrate; the tin salt is selected from one or more of stannous chloride and stannous sulfate; the molar ratio of the copper salt to the tin salt is 1:4 to 4:1, preferably 2:3 to 3:2; the copper salt is preferably copper chloride; and the tin salt is preferably stannous chloride.

[0042] Furthermore, in step S1, the stabilizer is a mixture of potassium sodium tartrate tetrahydrate and a nitrogen-containing compound; the nitrogen-containing compound is selected from any one or more of urea, ammonia, and ethylenediamine; the concentration of potassium sodium tartrate tetrahydrate is 1 to 4 mM, preferably 2 to 3 mM; the concentration of the nitrogen-containing compound is 4 to 1 mM, preferably 3 to 2 mM; and the molar ratio of potassium sodium tartrate hydrate to the nitrogen-containing compound is 2:3 to 3:2. The stabilizer is preferably a mixture of potassium sodium tartrate tetrahydrate and urea.

[0043] Furthermore, in step S1, the total molar concentration of the copper salt and the tin salt is equal to the total molar concentration of the stabilizer.

[0044] Furthermore, in step S1, aging is performed under stirring at room temperature, with a stirring speed of 400 to 600 rpm, preferably 500 rpm, and an aging time of 10 to 18 hours, preferably 12 to 14 hours.

[0045] S2: Processing copper substrate

[0046] Treat the copper substrate by using 10 mL of 2-10 M hydrochloric acid, ethanol, and ultrapure water in an ultrasonic cleaner for 20 minutes to clean it.

[0047] Furthermore, in step S2, the copper substrate is selected from any one of copper foam, copper mesh, copper plate, and copper foil. The copper substrate is preferably a copper mesh. The mesh size of the copper mesh substrate is 20 to 400, preferably 100 to 200. The wire diameter of the copper mesh is 0.04 to 0.13 mm, preferably 0.05 to 0.08 mm.

[0048] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0049] The copper substrate treated in S2 is placed in the CuSn precursor solution prepared in S1 for square wave voltammetry electrodeposition.

[0050] Furthermore, in step S3, the specific parameters of the square wave voltammetry electrodeposition are set as follows: the starting potential is set to +0.1V to +0.8V, preferably +0.2V to +0.6V; the ending potential is set to -1.0V to -1.8V, preferably -1.2V to -1.6V; the pulse height is 10mV to 50mV, preferably in the range of 20mV to 40mV; the step height is 5mV to 35mV, preferably in the range of 10mV to 30mV; and the frequency is set to 5Hz to 35Hz, preferably in the range of 10Hz to 30Hz. The ending potential is always lower than the starting potential.

[0051] S4: Cleaning

[0052] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain Cu x Sn y Bimetallic catalysts.

[0053] Example 1

[0054] A method for preparing a Cu2Sn3 bimetallic catalyst,

[0055] S1: Prepare CuSn precursor solution and perform aging treatment

[0056] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0057] S2: Processing copper substrate

[0058] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0059] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0060] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0061] S4: Cleaning

[0062] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 bimetallic catalyst.

[0063] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Metal nanoparticles with a particle size of 10 to 80 nm. The loading of the bimetallic layer is 17.6 mg / cm 2 , wherein the molar content of Cu is 40% and the molar content of Sn is 60%.

[0064] Example 2

[0065] A preparation method of Cu3Sn2 bimetallic catalyst,

[0066] S1: Prepare CuSn precursor solution and perform aging treatment

[0067] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 3 mM cupric chloride dihydrate, 2 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0068] S2: Processing copper substrate

[0069] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0070] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0071] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0072] S4: Cleaning

[0073] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu3Sn2 bimetallic catalyst.

[0074] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles with a particle size of 8 to 75 nm. The loading of the bimetallic layer is 16.7 mg / cm 2 , wherein the molar content of Cu is 60% and the molar content of Sn is 40%.

[0075] Example 3

[0076] A method for preparing a Cu4Sn1 bimetallic catalyst,

[0077] S1: Prepare CuSn precursor solution and perform aging treatment

[0078] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 4 mM cupric chloride dihydrate, 1 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0079] S2: Processing copper substrate

[0080] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0081] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0082] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0083] S4: Cleaning

[0084] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu4Sn1 bimetallic catalyst.

[0085] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles with a particle size of 6 to 68 nm. The loading of the bimetallic layer is 14.8 mg / cm 2 , wherein the molar content of Cu is 80% and the molar content of Sn is 20%.

[0086] Example 4

[0087] A preparation method of Cu1Sn4 bimetallic catalyst,

[0088] S1: Prepare CuSn precursor solution and perform aging treatment

[0089] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 1 mM cupric chloride dihydrate, 4 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0090] S2: Processing copper substrate

[0091] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0092] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0093] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0094] S4: Cleaning

[0095] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu1Sn4 bimetallic catalyst.

[0096] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles with a particle size of 20 to 100 nm. The loading of the bimetallic layer is 19.4 mg / cm 2 , wherein the molar content of Cu is 20% and the molar content of Sn is 80%.

[0097] Example 5

[0098] A method for preparing a Cu2Sn3 (-1.2V) bimetallic catalyst,

[0099] S1: Prepare CuSn precursor solution and perform aging treatment

[0100] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0101] S2: Processing copper substrate

[0102] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0103] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0104] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.2 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0105] S4: Cleaning

[0106] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (-1.2V) bimetallic catalyst.

[0107] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles with a particle size of 10 to 80 nm. The loading of the bimetallic layer is 16.2 mg / cm 2 , wherein the molar content of Cu is 35% and the molar content of Sn is 65%.

[0108] Example 6

[0109] A method for preparing a Cu2Sn3 (-1.6V) bimetallic catalyst,

[0110] S1: Prepare CuSn precursor solution and perform aging treatment

[0111] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0112] S2: Processing copper substrate

[0113] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0114] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0115] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.6 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0116] S4: Cleaning

[0117] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (-1.6V) bimetallic catalyst.

[0118] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 10-80nm. The loading of the bimetallic layer is 18.8mg / cm 2 , wherein the molar content of Cu is 45% and the molar content of Sn is 55%.

[0119] Example 7

[0120] A method for preparing a Cu2Sn3 (+0.2V) bimetallic catalyst,

[0121] S1: Prepare CuSn precursor solution and perform aging treatment

[0122] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0123] S2: Processing copper substrate

[0124] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0125] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0126] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.2 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0127] S4: Cleaning

[0128] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (+0.2V) bimetallic catalyst.

[0129] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 10-80nm. The loading of the bimetallic layer is 19.3mg / cm 2 , wherein the molar content of Cu is 47% and the molar content of Sn is 53%.

[0130] Example 8

[0131] A method for preparing a Cu2Sn3 (+0.6V) bimetallic catalyst,

[0132] S1: Prepare CuSn precursor solution and perform aging treatment

[0133] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0134] S2: Processing copper substrate

[0135] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0136] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0137] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.6 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0138] S4: Cleaning

[0139] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (+0.6V) bimetallic catalyst.

[0140] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 10-80nm. The loading of the bimetallic layer is 15.9mg / cm 2 , wherein the molar content of Cu is 29% and the molar content of Sn is 71%.

[0141] Example 9

[0142] A preparation method of Cu2Sn3 (30Hz) bimetallic catalyst,

[0143] S1: Prepare CuSn precursor solution and perform aging treatment

[0144] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0145] S2: Processing copper substrate

[0146] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0147] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0148] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 30 Hz.

[0149] S4: Cleaning

[0150] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (30 Hz) bimetallic catalyst.

[0151] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 5-70nm. The loading of the bimetallic layer is 15.8mg / cm 2 , wherein the molar content of Cu is 38% and the molar content of Sn is 62%.

[0152] Example 10

[0153] A preparation method of Cu2Sn3 (10Hz) bimetallic catalyst,

[0154] S1: Prepare CuSn precursor solution and perform aging treatment

[0155] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0156] S2: Processing copper substrate

[0157] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0158] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0159] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 10 Hz.

[0160] S4: Cleaning

[0161] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (10 Hz) bimetallic catalyst.

[0162] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 15-90nm. The loading of the bimetallic layer is 19.6g / cm 2 , wherein the molar content of Cu is 44% and the molar content of Sn is 56%.

[0163] Comparative Example 1

[0164] A preparation method of a Cu0Sn5 catalyst,

[0165] S1: Prepare CuSn precursor solution and perform aging treatment

[0166] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 0 mM cupric chloride dihydrate, 5 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0167] S2: Processing copper substrate

[0168] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0169] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0170] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0171] S4: Cleaning

[0172] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu0Sn5 catalyst.

[0173] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 25-110nm. The loading of the bimetallic layer is 21.7mg / cm 2 , wherein the molar content of Cu is 2% and the molar content of Sn is 98%.

[0174] Comparative Example 2

[0175] A preparation method of a Cu5Sn0 catalyst,

[0176] S1: Prepare CuSn precursor solution and perform aging treatment

[0177] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 5 mM cupric chloride dihydrate, 0 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0178] S2: Processing copper substrate

[0179] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0180] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0181] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0182] S4: Cleaning

[0183] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu5Sn0 catalyst.

[0184] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 5-60nm. The loading of the bimetallic layer is 12.9mg / cm 2 , wherein the molar content of Cu is 100%.

[0185] Comparative Example 3

[0186] A method for preparing a Cu2Sn3 (without potassium sodium tartrate tetrahydrate) bimetallic catalyst.

[0187] S1: Prepare CuSn precursor solution and perform aging treatment

[0188] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 0 mM potassium sodium tartrate tetrahydrate, and 5 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. After stirring, age the solution for 13 hours.

[0189] S2: Processing copper substrate

[0190] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0191] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0192] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0193] S4: Cleaning

[0194] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (without potassium sodium tartrate tetrahydrate) bimetallic catalyst.

[0195] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 50-150nm. The loading of the bimetallic layer is 18.2mg / cm 2 , wherein the molar content of Cu is 48% and the molar content of Sn is 52%.

[0196] Comparative Example 4

[0197] A method for preparing a Cu2Sn3 (nitrogen-free) bimetallic catalyst.

[0198] S1: Prepare CuSn precursor solution and perform aging treatment

[0199] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 5 mM potassium sodium tartrate tetrahydrate, and 0 mM urea. Stir the solution at 500 rpm at room temperature throughout the preparation process. Afterwards, age the solution with stirring for 13 hours.

[0200] S2: Processing copper substrate

[0201] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0202] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0203] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0204] S4: Cleaning

[0205] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (nitrogen-free) bimetallic catalyst.

[0206] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 80-200nm. The loading of the bimetallic layer is 16.8cm 2 , wherein the molar content of Cu is 64% and the molar content of Sn is 36%.

[0207] Comparative Example 5

[0208] A method for preparing a Cu2Sn3 (non-aging) bimetallic catalyst,

[0209] S1: Prepare CuSn precursor solution

[0210] Prepare 200 mL of a CuSn precursor solution containing cupric chloride dihydrate, stannous chloride dihydrate, potassium sodium tartrate tetrahydrate, and urea. The solution contains 2 mM cupric chloride dihydrate, 3 mM stannous chloride dihydrate, 2.5 mM potassium sodium tartrate tetrahydrate, and 2.5 mM urea. Do not age the entire solution and proceed directly to the next step.

[0211] S2: Processing copper substrate

[0212] A 200-mesh copper mesh (1 cm x 1.2 cm, 0.1 mm thick) was ultrasonically cleaned for 20 minutes using 10 mL of 5 M hydrochloric acid, ethanol, and ultrapure water, respectively, to remove surface dirt, oxides, and organic impurities. After cleaning, the mesh was dried with nitrogen.

[0213] S3: In situ electrodeposition on copper substrates using square wave voltammetry

[0214] A three-electrode system was constructed in a square electrolytic cell, using a pre-treated Cu mesh as the working electrode, an Ag / AgCl electrode as the reference electrode, and a 1.5 cm x 2 cm platinum sheet as the counter electrode. Square-wave voltammetry was performed on an aged CuSn precursor solution. The initial potential was +0.4 V, the final potential was -1.4 V, the pulse height was 30 mV, the step height was 20 mV, and the frequency was 20 Hz.

[0215] S4: Cleaning

[0216] The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain a Cu2Sn3 (non-aged) bimetallic catalyst.

[0217] Through characterization analysis, the nanoparticles uniformly deposited on the Cu mesh are Cu x Sn y Bimetallic nanoparticles, particle size 10-150nm. The loading of the bimetallic layer is 14.2mg / cm 2 , wherein the molar content of Cu is 31% and the molar content of Sn is 69%.

[0218] Applied Research

[0219] The catalysts prepared in the examples and comparative examples were used to perform the electroreduction of carbon dioxide. The distribution of the reduction products is shown in Table 1.

[0220] The catalysts prepared in the embodiment and the comparative example were respectively applied. The catalysts were washed with 100 ml of deionized water and dried with nitrogen, and then used as working electrodes for the electroreduction of carbon dioxide. An Ag / AgCl electrode was selected as the reference electrode, and a 1 cm×1 cm platinum sheet was selected as the counter electrode. An H-type electrolytic cell was used for the electroreduction of carbon dioxide. The cathode chamber and the anode chamber were separated by a proton exchange membrane. The two chambers were each filled with 40 mL of 0.5 M KHCO 3 . The working electrode and the reference electrode were fixed in the cathode chamber, and the counter electrode was fixed in the anode chamber. 99.999% high-purity carbon dioxide was introduced into the cathode chamber at a flow rate of 35 sccm. The reaction began after 30 min of carbon dioxide saturation, and the reduction reaction was tested by applying voltages of -1.8 V, -1.9 V, and -2.0 V (vs. Ag / AgCl).

[0221] Table 1. Distribution of reduction products of Examples and Comparative Examples

[0222]

[0223]

[0224]

[0225] Specifically, the difference between Example 1 and Example 2, Example 3, and Example 4 in Table 1 is that the ratio of the two metal ions in the CuSn precursor solution is different. In Example 1, the ratio of the two metal ions of Cu and Sn is n Cu :n Sn =x:y=2:3, the Faradaic efficiency of formic acid at -1.9V (FE HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Example 2 Cu, Sn two metal ion ratio is 3:2, at -1.9V FE of formic acid HCOOH is 81.56%, while the FE of hydrogen H2 In Example 3, the ratio of Cu and Sn metal ions is 4:1, and the FE of formic acid at -1.9V is 18.34%. HCOOH is 76.98%, while the FE of hydrogen H2 In Example 4, the ratio of Cu and Sn metal ions is 1:4, and the FE of formic acid at -1.9V is 30.02%. HCOOH is 84.34%, while the FE of hydrogen H2 is 14.66%. Overall, the Faraday efficiency of formic acid reaches its highest at -1.9V, and shows a trend of first increasing and then decreasing with the increase of the ratio of Cu and Sn metal ions. Cu :n Sn=x:y=2:3, the Faraday efficiency of formic acid reaches the highest, indicating that the Cu prepared under this condition x Sn y The two metals in the bimetallic catalyst can play a suitable coordinated role with each other, which can greatly promote the formation of the intermediate *OCHO during the catalytic reaction, and then promote the conversion of carbon dioxide to formic acid.

[0226] Specifically, the difference between Example 1 and Example 5 and Example 6 in Table 1 is that the final potential of the square wave voltammetry is different. In Example 1, the final potential is -1.4 V, and the Faradaic efficiency (FE) of formic acid at -1.9 V is HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Example 5, the final potential is -1.2V, at -1.9V FE of formic acid HCOOH is 83.14%, while the FE of hydrogen H2 is 16.67%; in Example 6, the final potential is -1.6V, and the FE of formic acid at -1.9V HCOOH is 85.23%, while the FE of hydrogen H2 It is 14.86%; as the final potential changes from -1.2V to -1.6V, it is found that when the final voltage is -1.4V, it is more conducive to the electrochemical reduction of carbon dioxide to formic acid.

[0227] Specifically, the difference between Example 1 and Examples 7 and 8 in Table 1 is that the initial potential of the square wave voltammetry is different. In Example 1, the initial potential is +0.4 V, and the Faradaic efficiency (FE) of formic acid at -1.9 V is HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Example 7, the initial potential +0.2V, at -1.9V when the FE of formic acid HCOOH is 79.94%, while the FE of hydrogen H2 In Example 8, the initial potential is +0.6V, and the FE of formic acid at -1.9V is 19.44%. HCOOH is 82.88%, while the FE of hydrogen H2 It is 16.65%; as the initial potential changes from +0.2V to +0.6V, it is found that when the initial voltage is +0.4V, it is more conducive to the electrochemical reduction of carbon dioxide to formic acid.

[0228] Specifically, the difference between Example 1 and Examples 9 and 10 in Table 1 is that the frequency of the square wave voltammetry is different. In Example 1, the frequency is 20 Hz, and the Faradaic efficiency (FE) of formic acid at -1.9 V is HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FEH2 ) 11.73%; Example 9, the frequency is 30Hz, at -1.9V FE of formic acid HCOOH is 73.64%, while the FE of hydrogen H2 In Example 10, the frequency is 10 Hz, and the FE of formic acid at -1.9 V is 31.47%. HCOOH is 77.79%, while the FE of hydrogen H2 It is 21.24%; as the frequency changes from 10Hz to 30Hz, it is found that when the frequency is 20Hz, it is more conducive to the electrochemical reduction of carbon dioxide to formic acid.

[0229] Specifically, the difference between Comparative Example 1 and Example 1 in Table 1 is that there is no Cu salt in the CuSn precursor solution of Comparative Example 1. The ratio of Cu and Sn metal ions in Example 1 is n Cu :n Sn =x:y=2:3, the Faradaic efficiency of formic acid at -1.9V (FE HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Comparative Example 1, the ratio of Cu and Sn metal ions is n Cu :n Sn =x:y=0:5, FE of formic acid at -1.9V HCOOH is 80.78%, while the FE of hydrogen H2 It is 18.43%; comparing the two, it is found that the Faradaic efficiency of formic acid has decreased because there is no synergistic effect of Cu and Sn metals, which affects the activity of the catalyst.

[0230] Specifically, the difference between Comparative Example 2 and Example 1 in Table 1 is that there is no Sn salt in the CuSn precursor solution of Comparative Example 2. The ratio of Cu and Sn metal ions in Example 1 is n Cu :n Sn =x:y=2:3, the Faradaic efficiency of formic acid at -1.9V (FE HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Comparative Example 2, Cu, Sn two metal ion ratio of 5:0, at -1.9V FE formic acid HCOOH is 32.72%, while the FE of hydrogen H2 Comparing the two, it is found that the Faradaic efficiency of formic acid has decreased because there is no synergistic effect of Cu and Sn, which affects the activity of the catalyst.

[0231] Specifically, the difference between Comparative Example 3 and Example 1 in Table 1 is that the CuSn precursor solution in Comparative Example 3 does not contain potassium sodium tartrate tetrahydrate. HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Comparative Example 3 CuSn precursor solution does not contain potassium sodium tartrate tetrahydrate, FE of formic acid at -1.9V HCOOH is 78.98%, while the FE of hydrogen H2 The Faraday efficiency of formic acid is 20.49%. The comparison between the two shows that the Faraday efficiency of formic acid is decreased because there is no potassium sodium tartrate tetrahydrate to complex with the two metal ions, especially Sn. 2+ , it is easy to hydrolyze in water, which is not conducive to precipitation during electrodeposition, thus affecting the activity of the catalyst.

[0232] Specifically, the difference between Comparative Example 4 and Example 1 in Table 1 is that there is no urea in the CuSn precursor solution of Comparative Example 4. The Faradaic efficiency (FE) of formic acid at -1.9 V in Example 1 is HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Comparative Example 4 CuSn precursor solution does not contain urea, at -1.9V FE of formic acid HCOOH is 82.37%, while the FE of hydrogen H2 It is 16.50%; comparing the two, it is found that the Faradaic efficiency of formic acid has decreased because there is no urea as a buffer to stabilize the pH value of the solution, which leads to large changes in local pH during the electrodeposition process, affecting the deposition rate of metal ions and the catalyst structure, and thus causing the Faradaic efficiency of formic acid to decrease.

[0233] Specifically, the difference between Comparative Example 5 and Example 1 in Table 1 is that the CuSn precursor solution in Comparative Example 5 was not subjected to aging treatment. HCOOH ) can reach 89.42%, while the Faraday efficiency of hydrogen is only (FE H2 ) 11.73%; Comparative Example 5 CuSn precursor solution was not aged, at -1.9V FE of formic acid HCOOH is 70.21%, while the FE of hydrogen H2 It is 28.56%; by comparing the two, it is found that the Faradaic efficiency of formic acid has decreased, which shows that the aging process is conducive to the complexation and dispersion of metal ions, so that the metal ions are evenly precipitated when voltage is applied.

[0234] Tests have shown that the catalyst has good catalytic activity for the electrocatalytic reduction of carbon dioxide and good selectivity for the single product, formic acid. Compared with existing technologies, the raw materials of the present invention are widely available and inexpensive, and the preparation process is simple and efficient, which is conducive to improving the conversion efficiency of carbon dioxide. It is an ideal and feasible electrochemical catalyst preparation scheme.

[0235] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A Cu x Sn y A bimetallic catalyst, characterized in that Cu loaded on the surface of the copper substrate x Sn y Bimetallic nanoparticles as catalysts, in which Cu x Sn y The bimetallic nanoparticles are recorded as bimetallic layers, the copper substrate is the base layer, and the Cu x Sn y The content of bimetallic nanoparticles is 5-30 mg / cm 2 , where x:y = 1:4 to 4:1; in the bimetallic layer, the molar content of Cu is 20 to 80%, and the molar content of Sn is 80 to 20%; the surface of the copper substrate is uniformly electrodeposited with Cu x Sn y Bimetallic nanoparticles, particle size is 10 to 80 nm.

2. A Cu as claimed in claim 1 x Sn y The preparation method of a bimetallic catalyst is characterized by: The specific steps include: S1: prepare CuSn precursor solution and perform aging treatment; A solution containing a copper salt, a tin salt, and a stabilizer in a certain proportion is prepared and aged under stirring to obtain a CuSn precursor solution; S2: Processing of copper substrate; Treat the copper substrate by using 10 mL of 2-10 M hydrochloric acid, ethanol, and ultrapure water in an ultrasonic cleaner for 20 minutes to clean it. S3: In situ electrodeposition on copper substrate using square wave voltammetry; The copper substrate treated in S2 is placed in the CuSn precursor solution prepared in S1 for square wave voltammetry electrodeposition. S4: cleaning; The catalyst prepared in step S3 was washed with 100 ml of deionized water and dried with nitrogen to obtain Cu x Sn y Bimetallic catalysts.

3. A Cu as claimed in claim 2 x Sn y The preparation method of a bimetallic catalyst is characterized by: In step S1, the copper salt is selected from one or more of copper chloride, copper sulfate, and copper nitrate; the tin salt is selected from one or more of stannous chloride and stannous sulfate; and the molar ratio of the copper salt to the tin salt is 1:4 to 4:

1.

4. A Cu as claimed in claim 2 x Sn y The preparation method of a bimetallic catalyst is characterized by: In step S1, the stabilizer is a mixture of potassium sodium tartrate tetrahydrate and a nitrogen-containing compound; the nitrogen-containing compound is selected from any one or more of urea, ammonia water, and ethylenediamine; wherein the concentration of potassium sodium tartrate tetrahydrate is 1 to 4 mM, the concentration of the nitrogen-containing compound is 4 to 1 mM, and the molar ratio of potassium sodium tartrate hydrate to the nitrogen-containing compound is 2:3 to 3:

2.

5. A Cu as claimed in claim 2 x Sn y The preparation method of a bimetallic catalyst is characterized by: In step S1, the total molar concentration of the copper salt and the tin salt is equal to the total molar concentration of the stabilizer.

6. A Cu as claimed in claim 2 x Sn y The preparation method of a bimetallic catalyst is characterized by: In the step S1, the stirring speed is 400-600 rpm, and the aging time is 10 h to 18 h.

7. A Cu as claimed in claim 2 x Sn y The preparation method of a bimetallic catalyst is characterized by: In step S2, the copper substrate is selected from any one of foam copper, copper mesh, copper plate, and copper foil.

8. A Cu as claimed in claim 2 x Sn y The preparation method of a bimetallic catalyst is characterized by: In step S3, the specific parameters of the square wave voltammetry electrodeposition are set as follows: the starting potential is set to +0.1V~+0.8V, the ending potential is set to -1.0V~-1.8V, the pulse height is 10mV~50mV, the step height is 5mV~35mV, the frequency is set to 5Hz~35Hz, and the ending potential is always lower than the starting potential.

9. Use of the catalyst prepared by the preparation method according to any one of claims 2 to 8 in electrochemical reduction of carbon dioxide, characterized in that: Cu x Sn y A bimetallic catalyst serves as the cathode.

10. The use according to claim 9, characterized in that: The electrolyte during electrochemical reduction of carbon dioxide is KHCO3; the electrolyte concentration is 0.1M to 1M.

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