Preparation method of copper-based nano-alloy bifunctional electrocatalyst and application thereof in hydrazine hydrate assisted hydrogen production

Abstract

The application discloses a preparation method of a copper-based nano-alloy bifunctional electrocatalyst and application of the copper-based nano-alloy bifunctional electrocatalyst in hydrazine hydrate assisted hydrogen production, and the preparation method comprises the following steps: adding a strong alkali aqueous solution dropwise into a copper salt aqueous solution, stirring, then adding a reducing agent aqueous solution dropwise until the liquid color turns red, continuing to stir, centrifuging, washing and drying a solid to obtain cuprous oxide nano-cubic particles; dispersing the cuprous oxide nano-cubic particles into a polar solvent, then adding a noble metal salt aqueous solution and sodium borohydride, uniformly stirring, centrifuging, washing and drying to obtain a copper-based nano-alloy precursor material; and dispersing the copper-based nano-alloy precursor material into a protic solvent, etching to obtain the copper-based nano-alloy bifunctional electrocatalyst. The use amount of the noble metal in the copper-based nano-alloy bifunctional electrocatalyst is obviously reduced to a commercial level, and the copper-based nano-alloy bifunctional electrocatalyst has good electrocatalytic performance and stability.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to a method for preparing a copper-based nano-alloy bifunctional electrocatalyst and its application in hydrazine hydrate-assisted hydrogen production. Background Technology

[0002] The depletion of fossil fuels and environmental problems have fueled widespread research enthusiasm for clean and renewable energy sources, such as water splitting devices, fuel cells, and metal-air / carbon dioxide batteries. Hydrogen energy, with its high energy density and zero carbon emissions, is considered the most promising energy source for solving the energy and environmental crisis. The hydrogen evolution reaction (HER) is a key half-reaction in the electrocatalytic splitting of water to produce hydrogen and is an ideal pathway for the large-scale production of high-purity hydrogen. To date, noble metal-based materials remain the best electrocatalysts for the HER. However, the high cost and scarcity of noble metal-based materials hinder their widespread application. Therefore, developing efficient non-noble metal-based materials or improving the atomic efficiency of noble metal-based hydrogen production is of great significance.

[0003] Introducing non-precious metals or using supports to reduce the use of precious metals has been widely reported as an effective means of preparing precious metal-based materials. Among all methods, copper-based alloys are a promising class of electrocatalysts, exhibiting excellent performance in electrocatalytic reactions such as hydrogen evolution reaction, oxygen reduction reaction, ethanol oxidation reaction, ethylene glycol oxidation reaction, and methanol oxidation reaction. However, reducing the amount of precious metals used in the alloys to a commercial level remains a challenge. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing copper-based nano-alloy bifunctional electrocatalysts. This method is simple, easy to implement, widely applicable, and highly safe, and can yield a series of copper-based nano-alloy bifunctional electrocatalysts.

[0005] Another objective of this invention is to provide a copper-based nano-alloy bifunctional electrocatalyst obtained by the above preparation method. The copper-based nano-alloy bifunctional electrocatalyst exhibits excellent hydrogen evolution and hydrazine hydrate oxidation performance under alkaline conditions, and also possesses excellent hydrazine hydrate-assisted hydrogen production performance.

[0006] The preparation method of the copper-based nano-alloy bifunctional electrocatalyst of the present invention is as follows: First, cuprous oxide nanocube particles are prepared, and noble metal salts and sodium borohydride used as a reducing agent are added to them as templates to deposit a copper-based alloy. Then, the alloy is dispersed in a proton solvent for etching to obtain the copper-based nano-alloy bifunctional electrocatalyst.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] A method for preparing a copper-based nano-alloy bifunctional electrocatalyst includes the following steps:

[0009] 1) Under stirring conditions, add a strong alkali solution to a copper salt aqueous solution at 30-90℃ to make the liquid color change from light green to blue and then to dark brown. Stir for 5-60 minutes, then add a reducing agent aqueous solution until the liquid color turns red. Continue stirring for 0.5-6 hours, centrifuge to obtain a solid, wash the solid, dry it to obtain cuprous oxide nanocube particles.

[0010] In step 1), the concentration of copper salt in the copper salt aqueous solution is 1-2 mg / mL.

[0011] In step 1), the copper salt is one or a mixture of copper chloride, copper sulfate, copper nitrate, copper acetylacetonate, and copper acetate; the strong base in the strong base aqueous solution is one or a mixture of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and calcium hydroxide; and the reducing agent in the reducing agent aqueous solution is one or a mixture of lithium borohydride, sodium borohydride, potassium borohydride, zinc borohydride, lithium ascorbate, sodium ascorbate, potassium ascorbate, calcium ascorbate, and ascorbic acid.

[0012] In step 1), the ratio of the copper salt aqueous solution, the strong alkali aqueous solution, and the reducing agent aqueous solution by volume is (10-1000):1:1, the concentration of the strong alkali in the strong alkali aqueous solution is 0.1-2M, and the concentration of the reducing agent in the reducing agent aqueous solution is 0.1-1M.

[0013] 2) Cuprous oxide nanocube particles are uniformly dispersed in a polar solvent, and then a noble metal salt aqueous solution and sodium borohydride are added. The mixture is stirred evenly, centrifuged, washed, and dried to obtain a copper-based nano-alloy precursor material. The ratio of the mass fraction of the cuprous oxide nanocube particles, the volume fraction of the polar solvent, the volume fraction of the noble metal salt aqueous solution, and the molar fraction of sodium borohydride is (5-50):(5-50):(5-25):(0.01-0.05). The volume fraction is in mL, the mass fraction is in mg, and the molar fraction is in mol.

[0014] In step 2), the noble metal salt is one or a mixture of several of the following: chloroplatinic acid, chloroiridiumic acid, chloroauric acid, chloropalladiumic acid, platinum acetylacetonate, palladium acetylacetonate, iridium acetylacetonate, and rhodium acetylacetonate.

[0015] In step 2), the concentration of the noble metal salt in the aqueous solution of the noble metal salt is 0.1-10 mg / mL.

[0016] In the above technical solution, the polar solvent is one or a mixture of several of N,N-dimethylformamide, N,N-dimethylacetamide, formamide, ethanol, methanol, chloroform and deionized water.

[0017] 3) Disperse the copper-based nano-alloy precursor material obtained in step 2) into a proton solvent and etch it at 10-80℃ for 0.5-24 hours to obtain a copper-based nano-alloy bifunctional electrocatalyst.

[0018] In step 3), the proton solvent is one or a mixture of several of hydrochloric acid, nitric acid and sulfuric acid.

[0019] The copper-based nano-alloy bifunctional electrocatalyst obtained by the above preparation method.

[0020] The application of the above-mentioned copper-based nanoalloy bifunctional electrocatalyst in hydrazine hydrate-assisted hydrogen production.

[0021] Compared with existing technologies, this invention provides a series of copper-based nano-alloy bifunctional electrocatalysts. These are obtained by using cuprous oxide nanocube particles as templates, through alloy deposition and template removal. The copper-based nano-alloy bifunctional electrocatalysts of this invention can be used simultaneously for hydrazine hydrate oxidation and hydrogen evolution reaction. Furthermore, by replacing the traditional anodic oxygen evolution reaction with hydrazine hydrate oxidation, a two-electrode electrolysis system is constructed, achieving highly efficient electrochemical hydrogen production.

[0022] The results show that the copper-based nanoalloy bifunctional electrocatalyst outperforms commercial platinum-carbon catalysts in both the hydrogen evolution reaction and hydrazine hydrate oxidation reaction at high current densities. This copper-based nanoalloy bifunctional electrocatalyst requires only low overpotentials of 258 mV and 668 mV to achieve 148 mA cm⁻¹ in both the hydrogen evolution reaction and the hydrazine hydrate oxidation reaction, respectively. -2 and 200mA cm -2 The performance is superior to commercial platinum-carbon catalysts (640 mV for hydrogen evolution reaction and 1081 mV for hydrazine hydrate oxidation reaction), and the corresponding Tafel slope of this bifunctional electrocatalyst (70.5 mV dec for hydrogen evolution reaction) is also superior. -1 The oxidation reaction of hydrazine hydrate is 40.1 mV dec. -1 The ratio is much smaller than that of Pt / C (hydrogen evolution reaction is 169.8 mV dec). -1 The oxidation reaction of hydrazine hydrate is 112.4 mV dec. -1 This copper-based nanoalloy bifunctional electrocatalyst exhibits excellent stability, capable of continuously performing hydrogen evolution reaction (HEP) for 70 hours and hydrazine hydrate oxidation reaction for 50 hours. The total hydrazine decomposition process utilizes this copper-based nanoalloy bifunctional electrocatalyst as both the anode and cathode electrodes, requiring only a small voltage of 0.59 V to achieve an A / C ratio of 178 mA. -2Its performance is also superior to that of commercial platinum-carbon catalysts (0.76V). In addition, the all-hydrazine decomposition can operate stably for more than 110 hours.

[0023] The copper-based nano-alloy bifunctional electrocatalyst of this invention significantly reduces the amount of precious metals used to a commercial level, while exhibiting good electrocatalytic performance and stability. Attached Figure Description

[0024] Figure 1 The images shown are (a) electron micrograph, (bc) X-ray diffraction pattern and (df) X-ray photoelectron spectroscopy pattern of the copper-based nano-alloy bifunctional electrocatalyst obtained in Example 1.

[0025] Figure 2 (a) HER curve, (b) corresponding Tafel plot, (c) weight-normalized overpotential and current density at different current densities, (d) EIS spectrum, (e) C dl Spectrum, (f) Example 1 at 10 mA cm -2 Electrocatalytic stability under [condition];

[0026] Figure 3 (a) HzOR curve, (b) corresponding Tafel plot, (c) Example 1 at 10 mA cm -2 Electrocatalytic stability of HzOR, (d) HzS curve, (e) LSV curves of HzS and OWS overpotentials in Example 1, (f) Electrocatalytic stability of Example 1 at 10 mA cm⁻¹ -2 Electrocatalytic stability of OHzS;

[0027] Figure 4 The morphology and phase diagrams of the copper-based nano-alloy bifunctional electrocatalyst obtained in Example 2 are as follows: (a) IrCu-1, (b) IrCu-2, (c) IrCu-3, (d) IrCu-4, (e) IrCu-5;

[0028] Figure 5 The following are the HER curves, corresponding Tafel plots, EIS spectra, and IrCu-4 spectra of the copper-based nanoalloy bifunctional electrocatalyst obtained in Example 2: (a) HER curve, (b) corresponding Tafel plot, (c) EIS spectra, and (d) IrCu-4 at 10 mA cm⁻¹. -2 HER electrocatalytic stability under these conditions;

[0029] Figure 6 The following are the HzOR curves (a), (b), and (c) images of the copper-based nano-alloy bifunctional electrocatalyst obtained in Example 2: (a) HzOR curve, (b) HzOR Tafel plot, and (c) IrCu-4 at 10 mA cm⁻¹. -2 Electrocatalytic stability of IrCu-9 at 10 mA cm⁻¹, (d) OHzS curve, (e) OWS curve, (f) IrCu-9 at 10 mA cm⁻¹ -2Electrocatalytic stability of OHzS;

[0030] Figure 7 The morphology and phase diagrams of the copper-based nano-alloy bifunctional electrocatalyst obtained in Example 3 are as follows: (a) AuCu-1, (b) AuCu-2, (c) AuCu-3, (d) AuCu-4, (e) AuCu-5;

[0031] Figure 8 The following are the HER curves, corresponding Tafel plots, EIS spectra, and AuCu-4 spectra of the copper-based nanoalloy bifunctional electrocatalyst obtained in Example 3: (a) HER curve, (b) corresponding Tafel plot, (c) EIS spectra, and (d) AuCu-4 at 10 mA cm⁻¹. -2 HER electrocatalytic stability under these conditions;

[0032] Figure 9 The following are the HzOR curves, Tafel plots, and AuCu-4 at 10 mA cm⁻¹ of the copper-based nanoalloy bifunctional electrocatalyst obtained in Example 3: (a) HzOR curve, (b) HzOR tafel plot, and (c) AuCu-4 at 10 mA cm⁻¹. -2 Electrocatalytic stability of AuCu-9 at 10 mA cm⁻¹: (d) OHzS curve, (e) OWS curve, (f) AuCu-9 at 10 mA cm⁻¹ -2 Electrocatalytic stability of OHzS. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0034] The instruments involved in the following embodiments are as follows:

[0035]

[0036]

[0037] The following examples involve the following pharmaceutical products:

[0038]

[0039]

[0040] When the copper-based nano-alloy bifunctional electrocatalysts obtained in Examples 1-3, the platinum-carbon catalyst in Comparative Example 1, and the platinum-copper alloy electrocatalyst obtained in Comparative Example 2 are used as samples for performance testing, the method for preparing the working electrode is as follows: Nafion membrane solution and ethanol are mixed at a volume ratio of 1:9 to obtain a mixed solution. 500 μL of ethanol and 500 μL of the mixed solution are mixed, and 2 mg of sample is added. The mixture is sonicated for 30 min to obtain a sample solution. Half of the sample solution is dropped onto a 1 cm x 1 cm piece of carbon paper using a pipette, and dried at 25 °C for 5 min to obtain the working electrode. The sample loading is 1 mg / cm². -2.

[0041] When a three-electrode system is used: the counter electrode is a platinum sheet electrode, and the reference electrode is a mercury / mercury oxide electrode.

[0042] The decomposition of all hydrazine (OHzS) and the decomposition of all water (OWS) were tested using a two-electrode system (both electrodes were working electrodes), with a polarization curve sweep rate of 10 mV / s.

[0043] The hydrogen evolution reaction (HER) and the oxidation reaction of hydrazine hydrate (HzOR) were tested using a three-electrode system (working electrode, counter electrode, and reference electrode), with a polarization curve sweep rate of 10 mV / s.

[0044] The electrolyte used in the decomposition of hydrazine (OHzS) and oxidation of hydrazine hydrate (HzOR) reactions contained 1M hydrazine hydrate and 1M potassium hydroxide, with the remainder being water. The electrolyte volume was 20 ml.

[0045] The electrolyte used in the hydrogen evolution reaction (HER) and total water splitting (OWS) is a 1M potassium hydroxide aqueous solution. The electrolyte volume is 20 ml.

[0046] Example 1

[0047] A method for preparing a copper-based nano-alloy bifunctional electrocatalyst includes the following steps:

[0048] 1) Under stirring conditions, a strong alkali solution was added dropwise to a copper salt aqueous solution at 65°C, causing the liquid color to change from light green to blue and then to dark brown. After stirring for 30 minutes, a reducing agent aqueous solution was added dropwise until the liquid color turned red. Stirring was continued for 3 hours, and the solution was centrifuged to obtain a solid. The solid was washed three times each with water and ethanol, and then dried in a vacuum oven at 60°C for 5 hours to obtain cuprous oxide nanocube particles. The concentration of copper salt in the copper salt aqueous solution was 1.69 mg / mL, and the copper salt was copper chloride. The strong alkali in the strong alkali aqueous solution was sodium hydroxide. The reducing agent in the reducing agent aqueous solution was ascorbic acid. The ratio of copper salt aqueous solution, strong alkali aqueous solution, and reducing agent aqueous solution by volume was 10:1:1. The concentration of strong alkali in the strong alkali aqueous solution was 2 M, and the concentration of reducing agent in the reducing agent aqueous solution was 0.6 M.

[0049] 2) Cuprous oxide nanocube particles were uniformly dispersed in a polar solvent, and then an aqueous solution of a noble metal salt was added. The mixture was stirred for 5 minutes, and sodium borohydride was quickly added. The mixture was stirred for 1 hour, centrifuged, and washed three times each with water and ethanol. The mixture was then dried at 60°C for 5 hours to obtain a copper-based nanoalloy precursor material. The ratio of the mass fraction of cuprous oxide nanocube particles, the volume fraction of the polar solvent, the volume fraction of the noble metal salt aqueous solution, and the molar fraction of sodium borohydride was 50:20:15:0.01. The volume fraction is expressed in mL, the mass fraction in mg, and the molar fraction in mol. The noble metal salt was chloroplatinic acid hexahydrate, and the concentration of the noble metal salt in the aqueous solution was 1 mg / mL. The polar solvent was deionized water.

[0050] 3) Disperse the copper-based nano-alloy precursor material obtained in step 2) into a proton solvent, and etch it at 25°C for 1 hour under ultrasonic conditions to obtain a copper-based nano-alloy bifunctional electrocatalyst, wherein the proton solvent is 0.1M hydrochloric acid.

[0051] Figure 1 The images show electron microscopy (EM) images, X-ray diffraction (XRD) patterns, and X-ray photoelectron spectroscopy (XPS) patterns of a copper-based nanoalloy bifunctional electrocatalyst (PtCu-NA). Figure 1 As shown in d, the X-ray photoelectron spectrum of PtCu-NA shows three main peaks at 40.5°, 47.2°, and 69.2°, belonging to (111), (200), and (220) of the platinum-copper alloy, respectively. Notably, the positions of all three peaks shift from platinum-copper to platinum, indicating that the interplanar spacing of PtCu-NA is larger than that of standard platinum-copper and closer to that of platinum. This can be attributed to the template-assisted synthesis method. In this method, cuprous oxide nanocube particles are selected as the copper precursor and self-sacrificing template, whose slow dissolution releases copper ions and allows the reduction of platinum to dominate the nucleation-growth process of the alloy. Furthermore, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of PtCu-NA show lattice spacings of (111) (0.223 nm) and (200) (0.193 nm), located between platinum-copper (0.219 nm, 0.194 nm) and platinum (0.224 nm, 1.90 nm), as... Figure 1 As shown in 'a', it is consistent with the X-ray diffraction pattern analysis, as... Figure 1 As shown in e and 1f.

[0052] Example 2

[0053] A method for preparing a copper-based nano-alloy bifunctional electrocatalyst includes the following steps:

[0054] 1) Under stirring conditions, a strong alkali solution was added dropwise to a copper salt aqueous solution at 65°C, causing the liquid color to change from light green to blue and then to dark brown. After stirring for 30 minutes, a reducing agent aqueous solution was added dropwise until the liquid color turned red. Stirring was continued for 3 hours, and the solution was centrifuged to obtain a solid. The solid was washed three times each with water and ethanol, and then dried in a vacuum oven at 60°C for 5 hours to obtain cuprous oxide nanocube particles. The concentration of copper salt in the copper salt aqueous solution was 1.69 mg / mL, and the copper salt was copper chloride. The strong alkali in the strong alkali aqueous solution was sodium hydroxide. The reducing agent in the reducing agent aqueous solution was ascorbic acid. The ratio of copper salt aqueous solution, strong alkali aqueous solution, and reducing agent aqueous solution by volume was 10:1:1. The concentration of strong alkali in the strong alkali aqueous solution was 2 M, and the concentration of reducing agent in the reducing agent aqueous solution was 0.6 M.

[0055] 2) Cuprous oxide nanocube particles were uniformly dispersed in a polar solvent, and then an aqueous solution of a noble metal salt was added. The mixture was stirred for 5 minutes, and sodium borohydride was quickly added. The mixture was stirred for 1 hour, centrifuged, and washed three times each with water and ethanol. The mixture was then dried at 60°C for 5 hours to obtain a copper-based nanoalloy precursor material. The ratio of the mass fraction of cuprous oxide nanocube particles, the volume fraction of the polar solvent, the volume fraction of the noble metal salt aqueous solution, and the molar fraction of sodium borohydride was 50:20:X:0.01. The unit of volume fraction is mL, the unit of mass fraction is mg, and the unit of molar fraction is mol. The noble metal salt was chloroiridic acid, and the concentration of the noble metal salt in the aqueous solution was 1 mg / mL. The polar solvent was deionized water.

[0056] 5 IrCu-1 10 IrCu-2 15 IrCu-3 20 IrCu-4 25 IrCu-5

[0057] 3) Disperse the copper-based nano-alloy precursor material obtained in step 2) into a proton solvent, and etch it at 25°C for 1 hour under ultrasonic conditions to obtain a copper-based nano-alloy bifunctional electrocatalyst, wherein the proton solvent is 0.1M hydrochloric acid.

[0058] Figure 4 The morphology and phase diagrams of the copper-based nanoalloy bifunctional electrocatalysts obtained in Example 2 are shown: (a) IrCu-1, (b) IrCu-2, (c) IrCu-3, (d) IrCu-4, and (e) IrCu-5. The morphology of the five copper-based nanoalloy electrocatalysts under SEM is displayed.

[0059] Example 3

[0060] A method for preparing a copper-based nano-alloy bifunctional electrocatalyst includes the following steps:

[0061] 1) Under stirring conditions, a strong alkali solution was added dropwise to a copper salt aqueous solution at 65°C, causing the liquid color to change from light green to blue and then to dark brown. After stirring for 30 minutes, a reducing agent aqueous solution was added dropwise until the liquid color turned red. Stirring was continued for 3 hours, and the solution was centrifuged to obtain a solid. The solid was washed three times each with water and ethanol, and then dried in a vacuum oven at 60°C for 5 hours to obtain cuprous oxide nanocube particles. The concentration of copper salt in the copper salt aqueous solution was 1.69 mg / mL, and the copper salt was copper chloride. The strong alkali in the strong alkali aqueous solution was sodium hydroxide. The reducing agent in the reducing agent aqueous solution was ascorbic acid. The ratio of copper salt aqueous solution, strong alkali aqueous solution, and reducing agent aqueous solution by volume was 10:1:1. The concentration of strong alkali in the strong alkali aqueous solution was 2 M, and the concentration of reducing agent in the reducing agent aqueous solution was 0.6 M.

[0062] 2) Cuprous oxide nanocube particles were uniformly dispersed in a polar solvent, and then an aqueous solution of a noble metal salt was added. The mixture was stirred for 5 minutes, and sodium borohydride was quickly added. The mixture was stirred for 1 hour, centrifuged, and washed three times each with water and ethanol. The mixture was then dried at 60°C for 5 hours to obtain a copper-based nanoalloy precursor material. The ratio of the mass fraction of cuprous oxide nanocube particles, the volume fraction of the polar solvent, the volume fraction of the noble metal salt aqueous solution, and the molar fraction of sodium borohydride was 50:20:Y:0.01. The unit of volume fraction is mL, the unit of mass fraction is mg, and the unit of molar fraction is mol. The noble metal salt was chloroauric acid, and the concentration of the noble metal salt in the aqueous solution was 1 mg / mL. The polar solvent was deionized water.

[0063] 5 AuCu-1 10 AuCu-2 15 AuCu-3 20 AuCu-4 25 AuCu-5

[0064] 3) Disperse the copper-based nano-alloy precursor material obtained in step 2) into a proton solvent, and etch it at 25°C for 1 hour under ultrasonic conditions to obtain a copper-based nano-alloy bifunctional electrocatalyst, wherein the proton solvent is 0.1M hydrochloric acid.

[0065] Figure 7 The morphology and phase diagrams of the copper-based nanoalloy bifunctional electrocatalysts obtained in Example 3 are shown: (a) AuCu-1, (b) AuCu-2, (c) AuCu-3, (d) AuCu-4, and (e) AuCu-5. The morphology of the five copper-based nanoalloy bifunctional electrocatalysts under SEM is illustrated.

[0066] Comparative Example 1

[0067] Platinum-carbon catalyst (Pt / C).

[0068] Comparative Example 2

[0069] A platinum-copper alloy electrocatalyst (PtCu-Cl) was prepared by dispersing 93 mg CuCl₂·2H₂O in 20 mL of ultrapure water. Then, 15 mL of an aqueous solution of chloroplatinic acid hexahydrate (H₂PtCl₆·6H₂O) (1 mg / mL) was added. After stirring for 5 minutes, 0.01 mol NaBH₄ was rapidly added. After stirring for another hour, the solid was collected by centrifugation and washed three times each with water and ethanol. The solid was dried in a vacuum oven at 60 °C for 5 hours, and then sonicated with 0.1 M HCl at 25 °C for 1 hour. The product was collected for later use.

[0070] Figure 2 The images show electrochemical analysis diagrams of the copper-based nano-alloy bifunctional electrocatalyst (PtCu-NA) obtained in Example 1, the platinum-carbon catalyst (Pt / C) in Comparative Example 1, and the platinum-copper alloy electrocatalyst (PtCu-Cl) obtained in Comparative Example 2. Figure 2 As shown in a, PtCu-NA requires an overpotential of 85.8 mV to provide 10 mA cm⁻¹. -2 This is higher than the overpotential of Pt / C (30 mV) but lower than the overpotential of PtCu-Cl (135 mV). The corresponding Tafel slope plot is shown below. Figure 2 In b, the Tafel slope of PtCu-NA is 70.5 mV dec. -1 The Tafel slope of PtCu-Cl is 146.7 mV dec. -1 The Tafel slope of Pt / C is 169.8 mV dec. -1 The value is much smaller, indicating that PtCu-NA has good HER reaction kinetics. Therefore, PtCu-NA at 26 mA cm⁻¹ -2 It exhibits the same 127mV overpotential as Pt / C, and even at 148mA cm⁻¹. -2 It exhibits an overpotential of 258 mV, far less than the 640 mV overpotential of Pt / C. At an overpotential of 258 mV, the activity of PtCu-NA is almost seven times that of Pt / C. Figure 2 As shown in c. The electron transfer characteristics of the prepared sample were determined by electrochemical impedance spectroscopy (EIS). The resistance values ​​include solution resistance (R). S ) and charge transfer resistance (R CT ).according to Figure 2 d, although the R of PtCu-NA S Slightly larger, but it shows the smallest R CT This means it has the fastest electron transfer. In 1 MkOH aqueous solution, at 10, 20, 30, 40, and 50 mV s... -1 The cyclic voltammetry (CV) curves of the prepared samples were recorded at the specified scan rate. The calculation results are as follows: Figure 2As shown in e, PtCu-Cl has the largest C dl The value is 43.6 mF cm -2 PtCu-NA and Pt / C show C dl The values ​​were 10.6 and 25.6 mF cm, respectively. -2 Furthermore, PtCu-NA exhibited sustained stability during 70 hours of continuous electrolysis without any loss of activity, such as... Figure 2 As shown in f.

[0071] Figure 3 Electrochemical analysis chromatograms of the copper-based nano-alloy bifunctional electrocatalyst (PtCu-NA) obtained in Example 1, the platinum-carbon catalyst (Pt / C) in Comparative Example 1, and the platinum-copper alloy electrocatalyst (PtCu-Cl) obtained in Comparative Example 2 are shown. HzOR Figure 3 As shown in figure a, it exhibits a trend similar to that of HER. To achieve 10 mA cm⁻¹, PtCu-NA... -2 An overpotential of 550 mV is required, which is higher than the 362 mV overpotential of Pt / C but lower than the 695 mV overpotential of PtCu-Cl. Calculate the corresponding Tafel plot and display it. Figure 3 In b, the Tafel slope of PtCu-NA is 40.1 mV dec. -1 It must be less than the Tafel slope of Pt / C, which is 112.4 mV dec. -1 The Tafel slope of PtCu-Cl is 81.5 mV dec. -1 This indicates that the HzOR of PtCu-NA also exhibits good reaction kinetics. Therefore, at 200 mA cm⁻¹ -2 At the specified current density, PtCu-NA requires only 668 mV overpotential, significantly lower than the overpotential of Pt / C (1081 mV). Furthermore, PtCu-NA exhibits robust stability during 50 hours of continuous electrolysis without any loss of activity. Figure 3 As shown in c. OHz S drives 10mA cm -2 The required current density is 0.34V, which is lower than the 10mA current density required by Pt / C driving a cm⁻¹. -2 The required current density is slightly higher than 0.24V. However, it only needs a potential of 0.59V to drive a 178mA cm⁻¹. -2 The current density is far superior to the 0.76V potential required by Pt / C, such as... Figure 3 As shown in d. In addition, the OWS performance of PtCu-NA was measured; it requires a potential of 2.01V to drive a 10mA cm⁻¹. -2 The current density is higher than that of 10mA cm⁻¹ driven by OHzS. -2 The current density is high at 1.667V, such as Figure 3As shown in e, in particular, OHzS can maintain long-term stability for over 110 hours, such as Figure 3 As shown in f.

[0072] Figure 5 This is an electrochemical analysis chromatogram of the copper-based nano-alloy electrocatalyst obtained in Example 2. (HER Ru) Figure 5 As shown in Figure a, IrCu-4 exhibits the best performance, requiring only a 127 mV overpotential to provide 10 mA cm⁻¹. -2 The overpotentials are less than those of IrCu-1 (192 mV), IrCu-2 (194 mV), IrCu-3 (147 mV), and IrCu-5 (135 mV). Calculate the corresponding Tafel slope plots and display them. Figure 5 In b, the Tafel slope of IrCu-1 is 602.5 mV dec. -1 The Tafel slope of IrCu-2 is 818.2 mVdec. -1 The Tafel slope of IrCu-3 is 168.1 mV dec. -1 The Tafel slope of IrCu-4 is 131.4 mV dec. -1 And the Tafel slope of IrCu-5 is 138.4 mV dec. -1 This indicates that IrCu-4 exhibits better HER reaction kinetics compared to the other four samples. According to... Figure 5 c. IrCu-4 exhibited the lowest charge transfer resistance relative to the other four samples, implying it had the fastest electron transfer. Furthermore, IrCu-4 demonstrated robust HER stability during 60,000 s continuous electrolysis without any loss of activity, such as... Figure 5 d.

[0073] Figure 6 This is an electrochemical analysis chromatogram of the copper-based nano-alloy electrocatalyst obtained in Example 2. (HzOR is shown in the image.) Figure 6 As shown in figure a, IrCu-4 requires only an overpotential of 281 mV to provide 10 mA cm⁻¹. -2 The overpotentials are less than those of IrCu-1 (435 mV), IrCu-2 (329 mV), IrCu-3 (367 mV), and IrCu-5 (351 mV). The corresponding Tafel slope plots are calculated and displayed. Figure 6 In b, the Tafel slope of IrCu-1 is 163.8 mV dec. -1 The Tafel slope of IrCu-2 is 197.5 mV dec. -1 The Tafel slope of IrCu-3 is 195.3 mV dec. -1 The Tafel slope of IrCu-4 is 124.8 mV dec.-1 And the Tafel slope of IrCu-5 is 170.9 mV dec. -1 This indicates that IrCu-4 exhibits superior HzOR reaction kinetics compared to the other four samples. Furthermore, IrCu-4 demonstrates robust HzOR stability during 60,000 s continuous electrolysis without any loss of activity, such as... Figure 6 c. The OFS performance of copper-based nanoalloy bifunctional electrocatalysts is as follows: Figure 6 As shown in d, IrCu-4 drives a 10mA cm -2 The required current density is 0.60 V, which is slightly lower than the required voltages of 0.64 V for IrCu-1, 0.73 V for IrCu-2, 0.68 V for IrCu-3, and 0.67 V for IrCu-5. Furthermore, the OWS performance of the copper-based nano-alloy bifunctional electrocatalyst was measured, such as... Figure 6 As shown in Figure e, IrCu-1 requires a voltage of 1.73V to drive a 10mA cm⁻¹. -2 The required current densities are as follows: IrCu-2 requires 1.71 V, IrCu-3 requires 1.48 V, IrCu-4 requires 1.76 V, and IrCu-5 requires 1.42 V. The data indicate that the OFS performance of the copper-based nano-alloy bifunctional electrocatalyst is superior to its OWS performance. Furthermore, IrCu-4 exhibits robust OFS stability during 50,000 s continuous electrolysis without any loss of activity. Figure 6 f.

[0074] Figure 8 This is an electrochemical analysis chromatogram of the copper-based nano-alloy electrocatalyst obtained in Example 3. (HER Ru) Figure 8 As shown in figure a, AuCu-4 requires an overpotential of 420 mV to provide 10 mA cm⁻¹. -2 The overpotentials are less than those of AuCu-1 (479 mV), AuCu-2 (469 mV), AuCu-3 (499 mV), and AuCu-5 (440 mV). Calculate the corresponding Tafel slope plots and display them. Figure 8 In b, the Tafel slope of AuCu-1 is 274.5 mV dec. -1 The Tafel slope of AuCu-2 is 229.6 mV dec. -1 The Tafel slope of AuCu-3 is 213.1 mV dec. -1 The Tafel slope of AuCu-4 is 202.5 mV dec. -1 And the Tafel slope of AuCu-5 is 253.4 mV dec. -1This indicates that AuCu-4 exhibits better HER reaction kinetics compared to the other four samples. According to... Figure 8 c, AuCu-4 exhibits the smallest charge transfer resistance (R) relative to the other four samples. CT This means it has the fastest electron transfer. Furthermore, IrCu-4 exhibits robust HER stability during 60,000 s continuous electrolysis without any loss of activity, such as... Figure 8 d.

[0075] Figure 9 The image shows the electrochemical analysis of the copper-based nano-alloy bifunctional electrocatalyst obtained in Example 3. (HzOR is not provided in the original text.) Figure 9 As shown in Figure a, AuCu-4 requires an overpotential of 278 mV to provide 10 mA cm⁻¹. -2 The overpotentials are less than those of AuCu-1 (341 mV), AuCu-2 (332 mV), AuCu-3 (293 mV), and AuCu-5 (317 mV). Calculate the corresponding Tafel slope plots and display them. Figure 9 In b, the Tafel slope of AuCu-1 is 154.4 mV dec. -1 The Tafel slope of AuCu-2 is 133.3 mV dec. -1 The Tafel slope of AuCu-3 is 136.7 mV dec. -1 The Tafel slope of AuCu-4 is 120.2 mV dec. -1 And the Tafel slope of AuCu-5 is 150.7 mV dec. -1 This indicates that AuCu-4 exhibits superior HzOR reaction kinetics compared to the other four samples. Furthermore, AuCu-4 demonstrates robust HzOR stability during 60,000 s continuous electrolysis without any loss of activity, such as... Figure 9 c. The OFS performance of copper-based nanoalloy bifunctional electrocatalysts is as follows: Figure 9 As shown in d. AuCu-4 drives 10mA cm -2 The required current density is 0.70 V, which is slightly lower than the required voltages of 0.85 V for AuCu-1, 0.90 V for AuCu-2, 0.80 V for AuCu-3, and 0.82 V for AuCu5. Furthermore, the OWS performance of the copper-based nano-alloy bifunctional electrocatalyst was measured, such as... Figure 9 As shown in Figure e, AuCu-1 requires a voltage of 2.1V to drive a 10mA cm. -2The required current densities were as follows: AuCu-2 required 2.2 V, AuCu-3 required 2.3 V, AuCu-4 required 1.60 V, and AuCu-5 required 1.62 V. The results indicate that the OFS performance of the copper-based nano-alloy bifunctional electrocatalyst is superior to that of OWS. Furthermore, AuCu-4 exhibited robust OFS stability during 60,000 s continuous electrolysis without any loss of activity. Figure 9 f.

[0076] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a copper-based nanoalloy bifunctional electrocatalyst, characterized in that, Includes the following steps: 1) Under stirring conditions, add a strong alkali aqueous solution to a copper salt aqueous solution at 30-90℃, so that the liquid color changes from light green to blue and then to dark brown. Stir for 5-60 minutes, then add a reducing agent aqueous solution until the liquid color turns red. Continue stirring for 0.5-6 hours, centrifuge to obtain a solid, wash the solid, dry it to obtain cuprous oxide nanocube particles. 2) Cuprous oxide nanocube particles are uniformly dispersed in a polar solvent, and then a noble metal salt aqueous solution and sodium borohydride are added. The mixture is stirred evenly, centrifuged, washed, and dried to obtain a copper-based nano-alloy precursor material. The ratio of the mass fraction of the cuprous oxide nanocube particles, the volume fraction of the polar solvent, the volume fraction of the noble metal salt aqueous solution, and the molar fraction of sodium borohydride is (5~50):(5~50):(5~25):(0.01-0.05). The volume fraction is in mL, the mass fraction is in mg, and the molar fraction is in mol. The noble metal salt is one or a mixture of several of chloroplatinic acid, chloroiridic acid, chloroauric acid, platinum acetylacetonate, and iridium acetylacetonate. 3) Disperse the copper-based nano-alloy precursor material obtained in step 2) into a proton solvent and etch it at 10-80℃ for 0.5-24 hours to obtain a copper-based nano-alloy bifunctional electrocatalyst. The proton solvent is hydrochloric acid.

2. The preparation method according to claim 1, characterized in that, In step 1), the concentration of copper salt in the copper salt aqueous solution is 1-2 mg / mL.

3. The preparation method according to claim 2, characterized in that, In step 1), the copper salt is one or a mixture of copper chloride, copper sulfate, copper nitrate, copper acetylacetonate, and copper acetate; the strong base in the strong base aqueous solution is one or a mixture of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and calcium hydroxide; and the reducing agent in the reducing agent aqueous solution is one or a mixture of lithium borohydride, sodium borohydride, potassium borohydride, zinc borohydride, lithium ascorbate, sodium ascorbate, potassium ascorbate, calcium ascorbate, and ascorbic acid.

4. The preparation method according to claim 3, characterized in that, In step 1), the ratio of the copper salt aqueous solution, the strong alkali aqueous solution, and the reducing agent aqueous solution by volume is (10~1000):1:1, the concentration of the strong alkali in the strong alkali aqueous solution is 0.1-2 M, and the concentration of the reducing agent in the reducing agent aqueous solution is 0.1-1 M.

5. The preparation method according to claim 4, characterized in that, In step 2), the concentration of the noble metal salt in the aqueous solution of the noble metal salt is 0.1-10 mg / mL.

6. The preparation method according to claim 5, characterized in that, The polar solvent is one or a mixture of several of N,N-dimethylformamide, N,N-dimethylacetamide, formamide, ethanol, methanol, chloroform, and deionized water.

7. The copper-based nanoalloy bifunctional electrocatalyst obtained by the preparation method according to any one of claims 1 to 6.

8. The application of the copper-based nanoalloy bifunctional electrocatalyst as described in claim 7 in hydrazine hydrate-assisted hydrogen production.

Images