A self-supporting multi-component highly dispersed noble metal thin film electrocatalyst and its preparation method

Abstract

The present invention provides a self-supporting multi-component highly dispersed precious metal thin film electrocatalyst and a preparation method thereof. A precious metal coordination compound thin film precursor M1M2DCl / F is prepared in situ on a conductive substrate by acid etching and in-situ deposition, and a calcination treatment is performed under a set atmosphere to obtain a self-supporting multi-component highly dispersed precious metal thin film electrocatalyst M1M2OAC / F. Wherein M1, M2, O, A, C, and F represent precious metal, non-precious metal, oxygen, non-metal, carbon, and conductive substrate, respectively. Since the precious metal and non-precious metal in the coordination compound precursor are dispersed at the atomic level, the precious metal is effectively isolated. During the calcination treatment, the precious metal is not easily agglomerated, forming extremely small nanoparticles that are embedded in the non-precious metal material, thereby optimizing the electronic structure and geometric structure of the precious metal. In addition, the catalyst layer is tightly bonded to the substrate. During the electrocatalytic reaction, reactants and electrons are rapidly transmitted and transferred, and the catalyst exhibits excellent hydrogen evolution catalytic activity and extremely high stability.

Description

[0001] Field

[0002] The present invention relates to the field of catalytic materials, and in particular to a self-supporting multi-component highly dispersed noble metal thin film electrocatalyst and a preparation method thereof. Background Art

[0003] The widespread use of fossil fuels has led to increasingly severe environmental pollution, climate change, and fossil resource depletion. The development of renewable, clean energy alternatives is urgently needed. Hydrogen, as an environmentally friendly, renewable, and clean energy source, is considered one of the most promising green energy sources. However, traditional hydrogen production methods, due to drawbacks such as greenhouse gas emissions and low production efficiency, cannot achieve green and sustainable production. In contrast, water electrolysis is an environmentally friendly method for hydrogen production.

[0004] Precious metal electrocatalysts (such as Pd, Pt, Au, Ir, Rh and Ru, etc.) have a great influence on the hydrogen evolution reaction (HER) in water electrolysis. ads The binding energy strength is moderate, showing excellent HER catalytic activity. Electrocatalysts are mainly divided into two categories: powder type and self-supporting type. Traditional powder type electrocatalysts are coated on the electrode with the help of adhesives (such as Nafion). The addition of adhesives is not conducive to the full contact between the electrocatalyst and the electrolyte, and causes an increase in contact resistance. In addition, since a large amount of hydrogen is released during the HER process, the powder sample coated on the electrode is very easy to fall off due to weak adhesion, resulting in a sharp decline in catalytic performance and a significant impact on the stability of the electrocatalyst.

[0005] Self-supporting electrocatalysts are monolithic catalysts prepared by in-situ growth of active substances on conductive substrates such as nickel foam, copper foam, iron foam, carbon cloth and stainless steel mesh. The in-situ grown active substances are tightly bound to the conductive substrate and are not easily lost during the HER process. At the same time, the electrocatalyst can be highly dispersed on the conductive substrate and is not easy to agglomerate, exposing more active sites. Literature Li K, Xu J, Chen C, Xie Z, Liu D, Qu D, Tang H, Wei Q, Deng Q, LiJ, Hu N. Journal of Colloid and Interface Science, 2021, 582: 591-597 A layer of NiO was first prepared on carbon cloth (CC) by electrochemical deposition, and then sulfur powder was used as the sulfur source to perform sulfurization treatment in an Ar atmosphere to obtain NiS2@CC. The NiS2@CC electrode immersed in H2PtCl6 solution was then heat-treated to obtain a Pt-NiS2@CC catalyst, which reached 50 mA cm in 0.5MH2SO4 solution. -2The overpotential is 139mV. The catalyst has the disadvantages of complex preparation method, low activity and poor stability. Reference Yang S, Zhu JY, Chen XN, Huang MJ, Cai SH, Han JY, Li JS. Applied Catalysis B: Environmental, 2022, 304: 120914 NiRu-LDH / NF was prepared on nickel foam (NF) by hydrothermal method, and then phosphating it to obtain Ni2P-Ru2P / NF catalyst. The catalyst was driven by 10, 100, and 200 mA cm in 1M KOH solution. -2 The overpotentials for the current densities were 101, 185, and 228 mV, and they suffered from defects such as excessive Ru dosage, low activity leading to high overpotentials, low energy efficiency, and poor stability. Therefore, the catalysts currently reported in the literature generally suffer from low activity, poor stability, complex preparation processes, and high precious metal usage, making them unable to meet the requirements of industrial production. Therefore, it is extremely important to develop new catalysts with high activity (low overpotential), good stability, low precious metal dosage, and low preparation cost.

[0006] In response to the many defects of current catalysts, the present invention proposes the idea of reducing the amount of precious metals used, optimizing the catalyst preparation process and catalyst structure to reduce catalyst costs and improve catalyst activity and stability. A layer of precious metal coordination compound thin film precursor is in situ constructed on a conductive substrate by acid etching and in situ deposition methods. By forming a coordination compound, the precious metal is highly dispersed in the non-precious metal material. The precious metal thin film self-supporting catalyst with strong bonding force to the substrate is prepared by calcination, which greatly reduces the amount of precious metals used, and optimizes the electronic structure and geometric structure of the precious metal through non-precious metals, significantly improving the activity and stability of the catalyst for the HER reaction. Summary of the Invention

[0007] The purpose of the present invention is to provide a self-supporting multi-component highly dispersed noble metal thin film electrocatalyst and a preparation method thereof, wherein the self-supporting multi-component highly dispersed noble metal thin film electrocatalyst has excellent water electrolysis hydrogen evolution activity and extremely high stability.

[0008] The self-supporting, multi-component, highly dispersed precious metal thin-film electrocatalyst provided by the present invention is represented by M1M2OAC / F, where M1 is a precious metal, M2 is a non-precious metal, O is oxygen, A is a non-metallic element, C is carbon, and F is a conductive substrate. This catalyst is characterized by a dense film, small particle size of precious metal and non-precious metal compounds, high precious metal dispersion, and a strong bond between the catalyst film and the conductive substrate, making it difficult to fall off.

[0009] The M1 is one or two of Pd, Pt, Au, Rh, Ru, and Ir, preferably any one or two of Pt, Ru, and Ir; the M2 is one or two of Ni, Co, Fe, Sc, Ti, V, Cr, W, Cu, Nb, Mo, Ta, La, and Ce, preferably one or two of Ni, Co, and Mo; the A is one or two of N, P, S, Se, and B, preferably one or two of P, Se, and B; the F is nickel, copper, iron, cobalt, and alloy metal sheets, wire mesh, or metal foam, preferably nickel foam, iron foam, and nickel-iron foam.

[0010] The present invention uses acid etching and in-situ deposition methods to in-situ prepare a precious metal coordination compound thin film precursor on a conductive substrate. The resulting precious metal thin film electrocatalyst is then calcined under a specific temperature and atmosphere. Because the precious metal and non-precious metal ions in the precious metal coordination compound precursor are atomically dispersed, the precious metal is less likely to agglomerate during the calcination process. Instead, it forms extremely small nanoparticles that are embedded in the non-precious metal material, significantly optimizing the precious metal's electronic structure and geometry, maintaining high activity and stability. Because the catalyst layer is tightly bonded to the substrate, rapid transfer of reactants and electrons is achieved during the electrocatalytic reaction, resulting in the catalyst exhibiting excellent HER activity and extremely high stability. Furthermore, the amount of precious metal used in the preparation process is significantly reduced, significantly reducing catalyst costs.

[0011] The preparation method of the self-supporting multi-component highly dispersed noble metal thin film electrocatalyst provided by the present invention comprises the following specific steps:

[0012] A. Dissolve the soluble M1 salt in the acid solution to prepare a uniform solution, in which M1 and [H + ] The molar ratio is 0.1 to 5:1, preferably 0.4 to 2:1, and then a sustained-release agent and an acidic ligand are added in sequence to obtain an M1 solution, wherein the molar ratio of the sustained-release agent to M1 is 2 to 20:1, preferably 5 to 10:1, and the molar ratio of the acidic ligand to M1 is 1 to 15:1, preferably 3 to 8:1.

[0013] The soluble M1 salt is any one or two of chlorates, chlorides, nitrates, sulfates and acetates of Pd, Pt, Au, Rh, Ru and Ir, preferably any one or two of chloropalladic acid, chloroplatinic acid, chloroauric acid, chloroiridic acid and ruthenium trichloride.

[0014] The acid solution is any one of hydrochloric acid, sulfuric acid and nitric acid, and the concentration is 0.5-3 mol / L.

[0015] The sustained-release agent is urea or hexamethylenetetramine.

[0016] The acidic ligand, abbreviated as D, is any one of ethylenediaminetetraacetic acid, citric acid, oxalic acid, lactic acid, salicylic acid, aminosalicylic acid, and glycine, preferably salicylic acid and aminosalicylic acid.

[0017] B. Add the M2 salt solution into the reactor, vertically place the pretreated conductive substrate F into the M2 salt solution, and heat at 50-100°C for 0.2-2 hours to activate the conductive substrate; then add the M1 solution into the reactor so that the molar ratio of M2 to M1 is 0.2-10:1, preferably 1-4:1, and the ratio of the mass of M1 in the reaction solution to the area of the conductive substrate is 0.05-2 mg / cm 2 , preferably 0.3~1mg / cm 2 ; Continue the reaction at 60-100℃ for 3-9 hours. The weak acidity of the solution causes the substrate to be etched, and M1, M2, D and Cl - A complex M1M2DCl is formed, and a thin film of atomically dispersed noble metal M1 and non-noble metal M2 is gradually formed on the surface of the F substrate. After the reaction, the conductive substrate is removed and washed 6 to 9 times with deionized water and anhydrous ethanol, and a dense M1M2DCl / F precursor film is obtained after drying.

[0018] The M2 salt solution is a solution prepared by mixing soluble M2 salt with deionized water, wherein the concentration of M2 is 0.1 to 50 mmol / L; the preferred concentration is 1 to 10 mmol / L; the soluble M2 salt is any one or two of the chlorides of Ni, Co, Fe, Sc, Ti, V, Cr, W, Cu, Nb, Mo, Ta, La, and Ce, and preferably one of the chlorides of Ni, Co, Cr, and Mo.

[0019] The conductive substrate F is a 0.02-3 mm thick sheet, wire mesh, or metal foam of nickel, copper, iron, cobalt, or their alloys, preferably nickel foam, iron foam, or nickel-iron foam. The conductive substrate pretreatment method comprises ultrasonicating the conductive substrate in 1-10 mol / L hydrochloric acid or sulfuric acid for 5-15 minutes to remove the surface oxide layer, then ultrasonicating the conductive substrate in anhydrous ethanol and deionized water for 3-5 minutes, respectively, and washing with deionized water until neutral.

[0020] C. Place the M1M2DCl / F precursor film prepared in step B and source A in a reaction furnace at the same time, wherein the molar ratio of source A to precious metal is 2-40:1, preferably 10-20:1; after sealing the reaction furnace, introduce gas at a flow rate of 10-1000 mL / min, and heat at 1-10 °C·min -1The sample was heated to 250-600°C at a constant temperature, calcined for 1-5 hours, and then cooled to obtain a self-supporting, multi-component, highly dispersed precious metal thin film electrocatalyst, M1M2OAC / F. This catalyst is characterized by a dense film, small particles of precious metal and non-precious metal compounds, high precious metal dispersion, and a strong bond between the catalyst film and the conductive substrate, making it difficult to fall off.

[0021] During the calcination process, the M1M2DCl precursor decomposes and reacts with the gas produced by the decomposition / volatilization of the non-metallic element doping raw material to be converted into carbon-loaded M1M2OA. At the same time, element A is doped into M1M2O to optimize the electronic structure and geometric structure of M1.

[0022] The source A is a non-metallic element raw material, and is one of a phosphorus source, a sulfur source, a selenium source, a boron source, and a nitrogen source. The phosphorus source is any one of sodium hypophosphite and red phosphorus. The sulfur source is any one of sulfur powder, thiourea, and thioacetamide. The selenium source is any one of selenium powder, sodium selenite, and ammonium selenide. The boron source is any one of sodium borohydride, boron powder, and sodium hypoborate. The nitrogen source is any one of urea, dicyandiamide, and melamine.

[0023] The gas is any one of nitrogen, ammonia, hydrogen, hydrogen-nitrogen mixed gas and hydrogen-argon mixed gas, wherein the volume of hydrogen in the hydrogen-nitrogen mixed gas and hydrogen-argon mixed gas is less than 20%; the gas is used to prevent oxidation of the conductive substrate during the calcination process.

[0024] The present invention uses acid etching and in-situ deposition methods to construct a M1M2DCl coordination compound film in which noble metals and non-noble metals are dispersed at the atomic level on the surface of a conductive substrate, and performs calcination treatment under a set atmosphere to obtain a non-metal A-doped multi-component highly dispersed noble metal thin film electrocatalyst; the noble metal film and the conductive substrate are connected by chemical bonds and are very tightly combined, so that the catalyst has good conductivity and low electron transfer resistance; because the noble metals and non-noble metals in the M1M2DCl precursor are dispersed at the atomic level, the noble metals and non-noble metals in the catalyst can be highly and evenly dispersed after calcination, exposing more active sites, which is conducive to the synergistic effect of the noble metals and non-noble metals, thereby making the multi-component highly dispersed noble metal thin film electrocatalyst have excellent catalytic activity and extremely high stability.

[0025] The obtained catalyst was characterized and its performance tested, and the results are as follows:

[0026] Figure 1 This is the FT-IR spectrum of RuNi(SA)Cl / N prepared in step C of Example 1. The characteristic absorption peak of salicylate (SA) appears in the spectrum, indicating the formation of a salicylic acid-based complex.

[0027] Figure 2This is the SEM photo of the precursor film. From the photo, we can see that the NF surface is covered with a thin film, and almost no large gaps can be seen, indicating that the prepared precursor film is very dense.

[0028] Figure 3 This is the EDS-Mapping photo of the precursor film. In the picture, the four elements Ni, Ru, O and C are evenly distributed on the NF, indicating that the Ni, Ru metals and ligands in the precursor are very evenly distributed.

[0029] Figure 4 This is the HRTEM photo of the precursor. There are almost no lattice fringes on it, and the intensity of the diffraction ring is also extremely weak, indicating that the precursor has low crystallinity and is almost an amorphous structure.

[0030] Figure 5 This is a SEM photograph of the RuNiOPC / NF catalyst obtained in Example 1. From the partially enlarged photograph, it can be seen that the prepared RuNiOPC / NF electrocatalyst film is very dense and has a rough surface.

[0031] Figure 6 This is an EDS-Mapping photo of the RuNiOPC / NF catalyst obtained in Example 1. In the photo, the five elements Ni, Ru, O, C and P are evenly distributed on the NF, indicating that the five elements Ni, Ru, O, C and P in the RuNiOPC / NF catalyst are very evenly distributed.

[0032] Figure 7 This is the HRTEM photo of the RuNiOPC / NF catalyst obtained in Example 1, in which the amorphous component is carbon material. The high-resolution photo shows the presence of RuO2, NiO and Ni2O3 crystalline phases and RuO2 is embedded in NiO and Ni2O3, indicating that RuO2, NiO and Ni2O3 are evenly dispersed on the amorphous carbon.

[0033] Figure 8 The performance test results of the RuNiOPC / NF catalyst obtained in Example 1 in 1M KOH solution are shown in the figure. As can be seen from the figure, the RuNiOPC / NF catalyst has excellent HER performance and its activity is significantly higher than that of the commercial Pt / C catalyst, reaching 100, 300 and 700 mA·cm -2 The overpotentials required for the current densities are as low as 75, 101, and 128 mV, respectively, and have a low Tafel slope (41.84 mV·dec -1 ), small impedance and high Faraday efficiency (96%).

[0034] Figure 9 The stability test results of the RuNiOPC / NF catalyst obtained in Example 1 are as follows. After 5000 cycles, the LSV curves of the catalysts are almost identical.-2 After running at the same current density for 500 h, the current density hardly decayed, indicating that RuNiOPC / NF has excellent working stability.

[0035] The present invention provides the following beneficial effects: A thin film of an M1M2DCl complex precursor containing atomically dispersed noble metal and non-noble metal ions is constructed on a conductive substrate by acid etching and in-situ deposition, and calcined under a predetermined atmosphere to yield a self-supporting multi-component, highly dispersed noble metal thin film electrocatalyst, M1M2OAC / F. Because the noble metal and non-noble metals in the precursor are atomically dispersed, the noble metal ions are effectively isolated. During calcination, the noble metal material is embedded in the non-noble metal material and amorphous carbon, making it less likely for the noble metal to agglomerate. This results in a highly dispersed noble metal thin film electrocatalyst with small particle size, high dispersion, and a dense structure that is firmly bonded to the substrate, fully exposing the catalyst's active sites. The P, S, Se, B, and N elements introduced into the catalyst optimize the electronic and geometric structures of the noble metals, enhancing their activity and stability. The conductive substrate has high conductivity and low electron transfer resistance, endowing the catalyst with rapid electron transfer capabilities. The combined effects of these factors result in a self-supporting noble metal thin film electrocatalyst with extremely high electrocatalytic hydrogen evolution activity and long-term operational stability. In addition, the present invention has the advantages of simple preparation method, mild reaction conditions, high precious metal conversion rate, and easy availability of raw materials, and has broad application prospects in catalysis fields such as industrial water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the FT-IR spectrum of the RuNi(SA)Cl / NF precursor obtained in Example 1.

[0037] Figure 2 These are SEM images of the RuNi(SA)Cl / NF precursor obtained in Example 1 at (a) 10K, (b) 20K, and (c) 50K magnifications.

[0038] Figure 3 This is the EDS-Mapping photo of the RuNi(SA)Cl / NF precursor obtained in Example 1, followed by the SEM photo and the Ni, Ru, O, and C element mapping photos.

[0039] Figure 4 HRTEM image (a) and SAED image (b) of the RuNi(SA)Cl / NF precursor obtained in Example 1.

[0040] Figure 5 These are SEM images of the RuNiOPC / NF catalyst obtained in Example 1 at (a) 10K, (b) 20K, and (c) 50K magnifications.

[0041] Figure 6 This is the EDS-Mapping photo of the RuNiOPC / NF catalyst obtained in Example 1, followed by the SEM photo and the Ni, Ru, O, C, and P element mapping photos.

[0042] Figure 7 HRTEM images of the RuNiOPC / NF catalyst obtained in Example 1 at (a) 100K and (b) 400K magnifications.

[0043] Figure 8 (a) LSV curve, (b) Tafel slope, (c) impedance, and (d) Faraday efficiency of the RuNiOPC / NF catalyst obtained in Example 1 in 1 M KOH solution.

[0044] Figure 9 5000 CV cycles (a) and constant voltage timing (b) test results of the RuNiOPC / NF catalyst obtained in Example 1 in 1 M KOH solution. DETAILED DESCRIPTION

[0045] Example 1:

[0046] A. Take 1 mL of 0.5 mol / L hydrochloric acid solution, add 10 mg of ruthenium trichloride to the hydrochloric acid solution, mix well, and then add 0.29 g of urea and 1 g of salicylic acid (SA) to obtain solution A.

[0047] B. Prepare 50mL of 0.1mmol / L nickel chloride solution; place nickel foam (NF) (3×5cm 2 ) was ultrasonically treated in 3 mol / L hydrochloric acid for 10 minutes to remove the surface oxide layer, and then ultrasonically treated in anhydrous ethanol and deionized water for 3 minutes respectively and washed with deionized water 5 times. The treated NF was placed vertically in the prepared nickel chloride solution and treated at 65°C for 1 hour to activate the NF. Then solution A was added, mixed evenly and the reaction was continued at 80°C for 3 hours. After the reaction was completed, the NF was taken out and washed with deionized water and anhydrous ethanol 5 times. After drying, the NF was prepared by the reaction of salicylic acid and Cl - The thin film electrocatalyst precursor RuNi(SA)Cl / NF is prepared with Ru and Ni as ligands and Ru and Ni are dispersed and dense at the atomic level. The obtained electrocatalyst precursor RuNi(SA)Cl / NF was characterized, and the results are shown in the attached Figure 1-4 , indicating that there are SA ligands in the film precursor, the crystallinity of the precursor is very low, almost an amorphous structure, and the formed film is uniform and dense.

[0048] C. The RuNi(SA)Cl / NF thin film electrocatalyst precursor prepared in step B was placed in a tube furnace together with 0.5 g of sodium hypophosphite. After sealing the tube furnace, nitrogen was introduced at a flow rate of 40 mL / min and the temperature was kept at 5 °C·min. -1 The sample was heated to 350°C at a heating rate of 1000 nm and calcined for 2 hours. After cooling, the sample was taken out to obtain a P-doped RuO2-based thin film electrocatalyst. Since Ru, Ni, O, P, and C elements coexist in the catalyst layer, the catalyst is abbreviated as RuNiOPC / NF.

[0049] The obtained electrocatalyst RuNiOPC / NF was characterized and the results are shown in the attached Figure 5-7 As can be seen from the figure, the catalyst film is very dense and the surface is very rough. The distribution of Ru, Ni, O, P, and C elements is very uniform. There are four substances: RuO2, NiO, Ni2O3, and amorphous carbon. P dopes RuO2, NiO, and Ni2O3, and RuO2 is embedded in NiO and Ni2O3 and evenly dispersed on amorphous carbon.

[0050] SEM and HRTEM characterization results (Appendix Figure 5-7 ) showed that the catalyst had small particle size, high dispersion, and very dense film. The film would not fall off from the NF substrate even after ultrasonic treatment for 2 h.

[0051] The HER performance of the catalyst was tested using a CHI660E electrochemical workstation in a standard three-electrode system. The electrolyte was 1 mol / L KOH solution. Hg / HgO and graphite electrodes were used as reference electrodes and counter electrodes, respectively. The potential value was corrected using 90% IR compensation and the reference electrode was 5 mV s -1 The linear sweep voltammetry (LSV) curve was tested at a scan rate of 100 nm and the catalyst stability was tested. The test results are shown in the attached Figure 8-9 The results showed that the catalyst has excellent HER performance in 1 M KOH solution, reaching 700 mA cm -2 The overpotential required for the current density is as low as 128 mV, which is significantly better than that of commercial Pt / C catalysts. It also shows a low Tafel slope and impedance, as well as a high Faradaic efficiency. Its performance does not change after 5000CV cycles. -2 After running for 500h at the same current density, the current density remained at 298mA·cm -2 , which is better than the catalysts reported in the literature. In addition, the catalyst reached 700 mA cm in 1 M PBS and 0.5 M H2SO4 solution. -2 The overpotentials required for the current densities of 100 nm and 100 nm are as low as 243 and 137 mV, respectively.

[0052] Example 2:

[0053] A. Take 1 mL of 2 mol / L hydrochloric acid solution, add 36 mg of palladium chloride to the hydrochloric acid solution, mix well, and then add 0.7 g of urea and 0.8 g of aminosalicylic acid (SAN) to obtain solution A.

[0054] B. Prepare 30mL of 3mmol / L ferric chloride solution; place NF (3×6cm 2 ) was ultrasonically treated in 5 mol / L hydrochloric acid for 10 minutes to remove the surface oxide layer. The surface oxide layer was then ultrasonically treated in anhydrous ethanol and deionized water for 5 minutes each and washed five times with deionized water. The treated NF was placed vertically in the solution and treated at 70°C for 0.5 hour to activate the NF. Solution A was then added to the reaction system, mixed well, and the reaction was continued at 80°C for 4 hours. After the reaction, the conductive substrate was removed and washed four times with deionized water and anhydrous ethanol. After drying, a PdFe(SAN)Cl / NF thin film precursor with atomically dispersed Pd and Fe and a dense structure was obtained.

[0055] C. Place the PdNi(SAN)Cl / NF precursor prepared in step B and 1g of sulfur powder in a tube furnace. After sealing the tube furnace, introduce argon at a flow rate of 50mL / min and heat at 2℃·min. -1 The sample was heated to 500 °C at a heating rate of 100 °C and calcined for 4 hours. After cooling, the sample was taken out to obtain a small-sized and dense precious metal Pd-based thin film electrocatalyst, which is represented by PdNiOSC / NF.

[0056] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed excellent HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 3 mV are respectively as low as 80, 222, and 103 mV.

[0057] Example 3:

[0058] A. Take 1 mL of 1 mol / L sulfuric acid solution, add 30 mg of chloroiridic acid to the sulfuric acid solution, mix well, and then add 0.79 g of hexamethylenetetramine and 0.4 g of ethylenediaminetetraacetic acid (EDTA) in sequence to obtain solution A.

[0059] B. Prepare 50 mL of a mixed solution of 3 mmol / L cobalt chloride and 3 mmol / L nickel chloride; 2) was ultrasonically treated in 5 mol / L sulfuric acid for 10 minutes to remove the surface oxide layer, followed by ultrasonication in anhydrous ethanol and deionized water for 3 minutes respectively and washing with deionized water five times. The NF was then placed vertically in the solution and treated at 75°C for 0.7 hour to activate the NF. Solution A was added to the reaction system, mixed evenly, and the reaction was continued at 90°C for 5 hours. After the reaction, the NF was removed and washed with deionized water and anhydrous ethanol six times. After drying, a dense and atomically dispersed Ir, Ni, and Co IrNiCo(EDTA)Cl / NF precursor was obtained.

[0060] C. The IrNiCo(EDTA)Cl / NF precursor prepared in step B was placed in a tube furnace with 0.5 g of dicyandiamide. A 10% hydrogen-argon mixture was introduced at a flow rate of 25 mL / min and heated at 5 °C / min. -1 The sample was heated to 250°C at a heating rate of 1000 nm and calcined for 2 hours. After cooling, a sample was taken out to obtain a small-sized and dense precious metal Ir-based thin film electrocatalyst, which was designated as IrNiCoONC / NF.

[0061] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed excellent HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 3 mV are as low as 97, 290, and 114 mV, respectively.

[0062] Example 4:

[0063] A. Take 2 mL of 0.3 mol / L nitric acid solution, add 20 mg of ruthenium acetate and 10 mg of chloroplatinic acid to the nitric acid solution, mix well, and then add 0.3 g of urea and 0.4 g of citric acid (CA) to obtain solution A.

[0064] B. Prepare 25mL of 20mmol / L nickel chloride solution; place the foam copper CF (3×5cm 2 ) was ultrasonically treated in 5 mol / L hydrochloric acid for 3 minutes to remove the surface oxide layer, and then ultrasonically treated in anhydrous ethanol and deionized water for 3 minutes respectively and washed with deionized water 6 times, and then CF was placed vertically in the solution and treated at 60°C for 30 minutes to activate CF; Solution A was added to the reaction system, mixed evenly, and continued to react at 85°C for 6 hours. After the reaction, the conductive substrate was removed and washed with deionized water and anhydrous ethanol 5 times, and dried to obtain a RuPtNi(CA)Cl / CF precursor in which Ru, Pt and Cu were atomically dispersed and dense.

[0065] C. The RuPtNi(CA)Cl / CF precursor prepared in step B was placed in a tube furnace together with 0.5 g of selenium powder. After sealing the tube furnace, nitrogen was introduced at a flow rate of 80 mL / min and the temperature was kept at 10 °C·min. -1 The sample was heated to 600°C at a heating rate of 1000 ℃ and calcined for 4 hours. After cooling, the sample was taken out to obtain a precious metal RuPt-based thin film electrocatalyst with small particle size, high dispersion and density, which was expressed as RuPtNiOSeC / CF.

[0066] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed excellent HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 30 mV are respectively as low as 95, 232, and 85 mV.

[0067] Example 5:

[0068] A. Take 1 mL of 0.5 mol / L sulfuric acid solution, add 10 mg of rhodium trichloride to the sulfuric acid solution, mix well, and then add 0.36 g of urea and 0.2 g of citric acid to obtain solution A.

[0069] B. Prepare 30 mL of a mixed solution with a cobalt chloride concentration of 20 mmol / L and a nickel chloride concentration of 10 mmol / L. Place the CF treated in Example 4 vertically into the solution and treat at 90°C for 0.5 hour to activate the CF. Add solution A to the reaction system, mix well, and continue the reaction at 90°C for 4 hours. After the reaction, remove the CF and wash it six times with deionized water and anhydrous ethanol. After drying, obtain a RhCo(CA)Cl / CF precursor in which Rh and Co are atomically dispersed and dense.

[0070] C. The RhCu(CA)Cl / CF precursor prepared in step B was placed in a tube furnace together with 0.5 g of melamine. After sealing the tube furnace, ammonia was introduced at a flow rate of 60 mL / min and the temperature was adjusted to 1 °C·min. -1 The sample was heated to 300°C at a heating rate of 1000 ℃ and calcined for 3 hours. After cooling, a sample was taken out to obtain a precious metal Rh-based thin film electrocatalyst with small particle size and high dispersion, which was expressed as RhCuONC / CF.

[0071] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed high HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 6 mV are respectively as low as 101, 228, and 106 mV.

[0072] Example 6:

[0073] A. Take 2 mL of 0.5 mol / L sulfuric acid solution, add 20 mg of chloroauric acid to the sulfuric acid solution, mix well, and then add 0.62 g of hexamethylenetetramine and 0.51 g of glycine (GA) in sequence to obtain solution A.

[0074] B. Prepare 35mL of 10mmol / L molybdenum chloride solution; place a cobalt sheet (CoF) with a thickness of 0.1mm (3×6cm 2 ) was ultrasonically treated in 6 mol / L hydrochloric acid for 5 minutes to remove the surface oxide layer, and then ultrasonically treated in anhydrous ethanol and deionized water for 3 minutes respectively and washed with deionized water 6 times, and then the cobalt sheet was placed vertically in the solution and treated at 80°C for 0.6 hour to activate the cobalt sheet; Solution A was added to the reaction system, mixed evenly, and then reacted at 90°C for 4 hours. After the reaction, the cobalt sheet was taken out and washed with deionized water and anhydrous ethanol 5 times, and dried to obtain an AuMo(GA)Cl / CoF precursor in which Au and Mo were atomically dispersed and dense.

[0075] C. The AuMo(GA)Cl / CoF precursor prepared in step B was placed in a tube furnace with 0.2 g of urea. After sealing the tube furnace, nitrogen was introduced at a flow rate of 80 mL / min and the temperature was kept at 5 °C·min. -1 The sample was heated to 400°C at a heating rate of 1000 nm and calcined for 2 hours. After cooling, the sample was taken out to obtain a precious metal Au-based thin film electrocatalyst with small particle size, high dispersion, density and strong bonding, which was expressed as AuMoONC / CoF.

[0076] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed excellent HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 30 mV are respectively as low as 104, 230, and 109 mV.

[0077] Example 7:

[0078] A. Take 3 mL of 0.5 mol / L nitric acid solution, add 35 mg of chloroplatinic acid to the nitric acid solution, mix well, and then add 0.36 g of urea and 0.566 g of glycine to obtain solution A.

[0079] B. Prepare 40 mL of a 30 mmol / L cerium chloride solution. Vertically place the NF treated in Example 1 into the solution and treat at 80°C for 0.5 h to activate the NF. Add Solution A to the reaction system, mix thoroughly, and continue the reaction at 85°C for 5 h. After the reaction, remove the NF and wash it four times with deionized water and anhydrous ethanol. After drying, obtain a PtCe(GA)Cl / NF precursor with atomically dispersed Pt and Ce.

[0080] C. Place the PtCe(GA)Cl / NF precursor prepared in step B and 0.4 g of boron powder in a tube furnace. After sealing the tube furnace, introduce argon at a flow rate of 60 mL / min and heat at 2 °C·min. -1 The sample was heated to 350°C at a heating rate of 1000 nm and calcined for 3 hours. After cooling, the sample was taken out to obtain a precious metal Pt-based thin film electrocatalyst with small particle size and strong bonding, which was expressed as PtCeONC / NF.

[0081] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed high HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 3 mV are respectively as low as 91, 243, and 83 mV.

[0082] Example 8:

[0083] A. Take 5 mL of 0.1 mol / L sulfuric acid solution, add 20 mg of palladium chloride and 15 mg of chloroplatinic acid to the sulfuric acid solution, mix well, and then add 0.14 g of urea and 0.17 g of ethylenediaminetetraacetic acid (EDTA) to obtain solution A.

[0084] B. Prepare 50mL of 40mmol / L cobalt chloride solution; place the foam iron (IF) (4×6cm 2 ) was ultrasonically treated in 1 mol / L hydrochloric acid for 5 minutes to remove the surface oxide layer, and then ultrasonically treated in anhydrous ethanol and deionized water for 3 minutes respectively and washed 4 times with deionized water. IF was placed vertically in the solution and treated at 55°C for 0.5 hour to activate IF; solution A was added to the reaction system and mixed evenly. After mixing evenly, the reaction was continued at 80°C for 4 hours. After the reaction was completed, the foamed iron was taken out and washed several times with deionized water and anhydrous ethanol. After drying, a PdPtCoFe(EDTA)Cl / IF precursor in which Pd, Pt, Co, and Fe were atomically dispersed and dense was obtained.

[0085] C. Place the PdPtCoFe(EDTA)Cl / IF precursor prepared in step B and 0.15g thiourea in a tube furnace. After sealing the tube furnace, introduce gas at a flow rate of 10mL / min and heat at 5℃·min. -1 The sample was heated to 350°C at a heating rate of 1000 nm and calcined for 2 hours. After cooling, the sample was taken out to obtain a precious metal PdPt-based thin film electrocatalyst with small particle size, high dispersion, density and strong bonding, which was expressed as PdPtCoFeOSC / IF.

[0086] The HER performance of the catalyst was tested in the same manner as in Example 1. The catalyst showed high HER performance in 1 M KOH, 1 M PBS, and 0.5 M H2SO4 solutions, reaching 700 mA·cm -2 The overpotentials required for the current densities of 1, 2, and 30 mV are respectively as low as 92, 234, and 87 mV.

[0087] The HER performances of the catalysts prepared in Examples 1-8 are summarized and the results are shown in Table 1.

[0088] Table 1

[0089]

Claims

1. A method for preparing a self-supporting multi-component highly dispersed noble metal thin film electrocatalyst, characterized by Prepare as follows: A. Dissolve the soluble M1 salt in the acid solution to prepare a uniform solution, in which M1 and [H + ] The molar ratio is 0.1 to 5:1; then a sustained-release agent and an acidic ligand are added in sequence to obtain an M1 solution, wherein the molar ratio of the sustained-release agent to M1 is 2 to 20:1; the molar ratio of the acidic ligand to M1 is 1 to 15:1; The soluble M1 salt is any one or two of chlorate, chloride, nitrate, sulfate and acetate of Pd, Pt, Au, Rh, Ru and Ir; The acid solution is any one of hydrochloric acid, sulfuric acid, and nitric acid, with a concentration of 0.5 to 3 mol / L; The sustained-release agent is urea or hexamethylenetetramine; The acidic ligand, abbreviated as D, is any one of ethylenediaminetetraacetic acid, citric acid, oxalic acid, lactic acid, salicylic acid, aminosalicylic acid, and glycine; B. Add the M2 salt solution into the reactor, vertically place the pretreated conductive substrate F into the M2 salt solution, and heat at 50-100°C for 0.2-2 hours to activate the conductive substrate; then add the M1 solution into the reactor so that the molar ratio of M2 to M1 is 0.2-10:1, and the ratio of the mass of M1 in the reaction solution to the area of the conductive substrate is 0.05-2 mg / cm 2 ; Continue the reaction at 60-100℃ for 3-9 hours. The weak acidity of the solution causes the substrate to be etched, and M1, M2, D and Cl - The complex M1M2DCl is formed, and a thin film of atomically dispersed noble metal M1 and non-noble metal M2 gradually forms on the surface of the F substrate. After the reaction, the conductive substrate is removed and washed 6 to 9 times with deionized water and anhydrous ethanol. After drying, a dense M1M2DCl / F precursor film is obtained. The M2 salt solution is a solution prepared by mixing a soluble M2 salt with deionized water, wherein the concentration of M2 is 0.1 to 50 mmol / L; the soluble M2 salt is any one or two of chlorides of Ni, Co, Fe, Sc, Ti, V, Cr, W, Cu, Nb, Mo, Ta, La, and Ce; The conductive substrate F is a 0.02-3 mm thick nickel, copper, iron, cobalt, or alloy metal sheet, wire mesh, or metal foam. The conductive substrate pretreatment method is as follows: ultrasonically immerse the conductive substrate in 1-10 mol / L hydrochloric acid or sulfuric acid for 5-15 minutes to remove the surface oxide layer, then ultrasonically immerse the conductive substrate in anhydrous ethanol and deionized water for 3-5 minutes respectively, and then wash with deionized water until neutral. C. Place the M1M2DCl / F precursor film prepared in step B and source A in a reaction furnace at the same time, wherein the molar ratio of source A to precious metal is 2-40:1; after sealing the reaction furnace, introduce gas at a flow rate of 10-1000 mL / min and heat at 1-10 °C·min -1 The sample is heated to 250-600°C at a heating rate of 10000 ℃ and calcined for 1-5 hours. After cooling, the sample is taken out to obtain a self-supporting multi-component highly dispersed noble metal thin film electrocatalyst M1M2OAC / F. The source A is a non-metallic element raw material, any one of sodium hypophosphite, red phosphorus, sulfur powder, thiourea, thioacetamide, selenium powder, sodium selenite, ammonium selenide, sodium borohydride, boron powder, sodium hypoborate, urea, dicyandiamide, and melamine; The gas is any one of nitrogen, ammonia, hydrogen, a hydrogen-nitrogen mixture, and a hydrogen-argon mixture, wherein the volume of hydrogen in the hydrogen-nitrogen mixture or the hydrogen-argon mixture is less than 20%; the gas is used to prevent oxidation of the conductive substrate during the calcination process; In the above-mentioned M1M2OAC / F, M1 is a precious metal, M2 is a non-precious metal, O is oxygen, A is a non-metallic element, C is carbon, and F is a conductive substrate. The catalyst is characterized by a dense film, small particle size of precious metal and non-precious metal compounds, high dispersion of precious metals, and a firm bond between the film and the conductive substrate that is not easy to fall off. The M1 is one or two of Pd, Pt, Au, Rh, Ru, and Ir; the M2 is one or two of Ni, Co, Fe, Sc, Ti, V, Cr, W, Cu, Nb, Mo, Ta, La, and Ce; the A is one or two of N, P, S, Se, and B; and the F is nickel, copper, iron, cobalt, and alloy metal sheets, wire mesh, or metal foam.

2. The method for preparing a self-supporting multi-component highly dispersed noble metal thin film electrocatalyst according to claim 1, characterized in that M1 described in step A and [H + ] The molar ratio is 0.4 to 2:1, the molar ratio of the sustained-release agent to M1 is 5 to 10:1, and the molar ratio of the acidic ligand to M1 is 3 to 8:1; the soluble M1 salt is any one or two of chloropalladic acid, chloroplatinic acid, chloroauric acid, chloroiridic acid, and ruthenium trichloride; the acidic ligand is salicylic acid and aminosalicylic acid; Step B. The molar ratio of M2 to M1 in the reaction solution in the reactor is 1 to 4:1, and the ratio of the mass of M1 to the area of the conductive substrate is 0.3 to 1 mg / cm 2 The concentration of the M2 salt solution is 1 to 10 mmol / L; soluble M2 salt Ni, Co, Cr, Mo chloride one; the conductive substrate F is nickel foam, iron foam and nickel-iron foam; In step C, the molar ratio of source A to the noble metal is 10 to 20:1.

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