Catalyst for anti-oxidation nickel-based fuel cell anode as well as preparation method and application of catalyst

Abstract

The invention belongs to the technical field of fuel cell anode catalysts, and particularly relates to an antioxidant nickel-based fuel cell anode catalyst and a preparation method and application thereof. The antioxidant nickel-based catalyst for the fuel cell anode has a core-shell structure and comprises nickel-based nanoparticles and a graphite layer coating the surfaces of the nickel-based nanoparticles, and a second metal site is loaded on the graphite layer. According to the catalyst, the metal Ni is coated by the graphite layer, so that oxidation in the reaction process is effectively inhibited; meanwhile, active sites of monatomic or nanoclusters on the graphite layer can promote efficient oxidative conversion of hydrogen, so that the HOR activity and oxidation resistance of the catalyst are remarkably improved. The design of the catalyst aims to consider both low cost and high performance, and solves the key technical bottlenecks of low activity, easy oxidation deactivation and the like of the nickel-based catalyst in the hydrogen energy fuel cell anode application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fuel cell anode catalysts, and particularly relates to an oxidation-resistant nickel-based fuel cell anode catalyst and a preparation method and application thereof. BACKGROUND

[0002] Fuel cell technology has become an important way to realize efficient and clean utilization of hydrogen energy due to its high efficiency and environmental protection. In fuel cell technology, hydrogen energy conversion technologies such as proton exchange membrane fuel cells (PEMFC) and anion exchange membrane fuel cells (AEMFC) have attracted much attention. Compared with the oxygen reduction reaction (ORR) at the cathode, the hydrogen oxidation reaction (HOR) at the anode has a lower overpotential, but the anode reaction still mainly relies on noble metal Pt-based catalysts. Therefore, reducing the amount of noble metal or developing non-Pt-based catalysts to reduce the cost of anode catalysts has become the focus of current research.

[0003] Nickel-based catalysts are widely studied for replacing Pt-based catalysts due to their low cost and close-to-Pt-based catalyst hydrogen bond energy (HBE). However, under the actual working conditions of fuel cells, even if high-load Pt / C catalysts are used at the cathode, the peak power density (PPD) of nickel-based catalysts is still difficult to reach 1.5 W / cm 2 In addition, nickel-based catalysts are easily oxidized when the working potential exceeds 0.15 V, leading to rapid deactivation of the catalyst. In the actual application of fuel cells, such as high output power or insufficient gas supply, high anode overpotential often occurs, which in turn causes catalyst oxidation and deactivation, seriously affecting its service life and cell stability, making it difficult for Ni-based catalysts to completely replace noble metal catalysts such as Pt / C and PtRu / C.

[0004] Currently, carbon coating, nitrogen doping, alloying and other technical means are used to improve the oxidation resistance potential of nickel-based catalysts, so that some nickel-based catalysts can work stably at potentials exceeding 0.3 V, but there are still problems of rapid deactivation in long-term cycling. SUMMARY

[0005] The purpose of the present application is to provide an oxidation-resistant nickel-based fuel cell anode catalyst and a preparation method and application thereof, so as to overcome the shortcomings of the prior art, and by designing the structure of the nickel-based catalyst, low cost and high performance are achieved, the problems of low activity and easy oxidation and deactivation of nickel-based catalysts in the application of hydrogen energy fuel cell anodes are solved, and the commercialization of the catalyst in the field of fuel cells is effectively promoted.

[0006] In order to achieve the above purpose, the technical scheme of the present application is as follows: In a first aspect, the present application provides a nickel-based oxidation-resistant catalyst having a core-shell structure, comprising nickel-based nanoparticles and a graphite layer coated on the surface of the nickel-based nanoparticles; the graphite layer is loaded with second metal sites.

[0007] The graphite layer in the novel oxidation-resistant nickel-based catalyst provided by the present application seals and coats the nickel alloy nanoparticles, effectively inhibiting oxidation during the reaction; at the same time, the second metal sites on the graphite layer can promote the efficient oxidation conversion of hydrogen, thereby significantly improving the HOR activity and oxidation resistance of the catalyst. The catalyst has low cost and high performance, and solves the key technical bottlenecks of low activity and easy oxidation inactivation of nickel-based catalysts in the anode application of hydrogen energy fuel cells.

[0008] In some other embodiments, the nickel-based nanoparticles are one of nickel metal nanoparticles and nickel alloy nanoparticles; the nickel alloy nanoparticles comprise a nickel matrix and a first metal, the first metal being one or more of Fe, Co, Mn, Cu, Ru, Pd, Ir, Mo, and W; the first metal accounts for 1.0 wt%-80 wt% of the mass of the nickel alloy nanoparticles.

[0009] The first metal used in the present application has a wide source and can significantly regulate the catalytic performance of nickel metal, realizing synergistic advantages through electronic structure modification, geometric effect optimization, and stability enhancement.

[0010] In some other embodiments, the number of layers of the graphite layer is 1-4 layers; The second metal site is one or more of Pt, Ru, Pd, Mo, Ir, Fe, Co, and Ni metal monatomic or nanoclusters; The second metal accounts for 0.1 wt%-10 wt % of the total mass of the catalyst, preferably, the second metal accounts for 1.0 wt%-2.0 wt % of the total mass of the catalyst.

[0011] For example, the second metal accounts for 0.1 wt%, 0.5 wt %, 1.0 wt %, 1.5 wt %, 2.0 wt %, 3.0 wt %, 4.0 wt %, 5.0 wt %, 6.0 wt %, 7.0 wt %, 8.0 wt %, 9.0 wt %, or 10 wt % of the total mass of the catalyst.

[0012] In some other embodiments, the graphite layer further contains a dopant, the dopant being one or more of S, P, Se, and N in the form of an element or a compound; the dopant accounts for 1.0 wt%-20 wt% of the mass of the graphite layer.

[0013] In a second aspect, the present application provides a preparation method of the nickel-based oxidation-resistant catalyst of the first aspect, comprising the following steps: A nickel-based catalyst coated with a graphite layer was prepared by pyrolysis of a mixture of a nickel source and a carbon source. The nickel-based catalyst coated with graphite layer is mixed with a second metal source and then subjected to heat treatment to obtain a nickel-based antioxidant catalyst.

[0014] This invention uses inexpensive nickel, a non-precious metal, as a raw material, resulting in low production costs. The antioxidant nickel-based fuel cell anode catalyst prepared using this invention exhibits excellent oxidation resistance and good battery performance, and is expected to replace platinum-carbon catalysts in fuel cells.

[0015] In some other embodiments, the mass ratio of the nickel source to the carbon source is 1:(0.5-10), preferably 1:(2-4); the mass ratio of the nickel source to the carbon source is specifically 1:2, 1:3 or 1:4.

[0016] The pyrolysis temperature is 300-1000℃, and the pyrolysis time is 1-5h; preferably, the temperature is 400-600℃, and the pyrolysis time is 2-3h; specifically, the temperature is 400℃, 500℃, or 600℃, and the pyrolysis time is 2h or 3h.

[0017] The nickel source is one or more of nickel nitrate, nickel chloride, nickel sulfate, and nickel acetylacetone; The carbon source is one or more of the following: ethylenediaminetetraacetic acid, tetrasodium ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, bipyridine, imidazole, melamine, dicyandiamide, cyanamide, urea, hexamethylenetetramine, thiol, oleic acid, stearic acid, oleylamine, sodium oleate, 4-aminocatechol, 2-amino-1,3-benzene, 4-amino-1,3-benzene, and 3,5-diaminophenol; Preferably, the nickel source is one of nickel nitrate and nickel chloride; The carbon source is ethylenediaminetetraacetic acid.

[0018] The carbon-coated nickel-based alloy composite material prepared by this invention is beneficial to improving the efficiency of catalytic reactions, especially exhibiting excellent catalytic effect and selectivity for ORR reactions. Its performance is comparable to that of Pt / C currently used in commercial applications, and it has good prospects for industrial application.

[0019] In some other embodiments, the loading of the second metal source is 0.1 wt% to 10 wt% of the mass of the graphite-coated nickel-based catalyst, preferably 1.0 wt% to 2.0 wt%. The heat treatment temperature is 200-1000℃, and the heat treatment time is 1-6 h; preferably, the heat treatment temperature is 300-700℃, and the heat treatment time is 3-5 h. The second metal source is one or more of Pt, Ru, Pd, Mo, Ir, Fe, Co, and Ni; Preferably, the second metal source is one of Ru and Pd.

[0020] The second metal single-atom or nanocluster active site on the graphite layer in this invention can promote the efficient oxidation conversion of hydrogen, thereby significantly improving the HOR activity and antioxidant performance of the catalyst. Replacing current precious metal catalysts, this approach helps reduce catalyst costs and facilitates further large-scale practical application and industrialization.

[0021] In some other embodiments, the preparation of the graphite-coated nickel-based catalyst further includes adding a first metal source, mixing the nickel source, the first metal source, and the carbon source, and then performing pyrolysis; the first metal source is one or more of Fe, Co, Mn, Cu, Ru, Pd, Ir, Mo, and W; The first metal accounts for 1.0 wt%-80 wt% of the mass of the nickel alloy nanoparticles.

[0022] It also includes modifying the nickel-based catalyst coated with graphite layer by mixing the nickel-based catalyst coated with graphite layer with a dopant and then performing a heating modification treatment; the dopant is one or more of elemental or compound S, P, Se and N; the dopant accounts for 1.0wt%-20wt% of the mass of the graphite layer.

[0023] The temperature for heat modification treatment is 200-300℃, and the time is 2-3 hours. For example, the temperature for heat modification treatment is 200℃, 220℃, 250℃ or 300℃, and the time is 2 hours or 3 hours.

[0024] The nano-metal particles of this invention are more tightly coated with graphitized carbon layers, and the electronic properties of the graphitized carbon layers can be adjusted to make them suitable for different catalytic reactions.

[0025] Thirdly, the present invention provides the application of the nickel-based antioxidant catalyst described in the first aspect in the anode of a fuel cell.

[0026] Fourthly, the present invention provides a fuel cell anode containing the nickel-based antioxidant catalyst described in the first aspect.

[0027] The beneficial effects of this invention are: (1) The antioxidant nickel-based catalyst prepared in this invention effectively inhibits oxidation during the reaction process by coating metallic Ni with a graphite layer; at the same time, the second metal single atom or nanocluster active sites on the graphite layer can promote the efficient oxidation conversion of hydrogen, thereby significantly improving the HOR activity and antioxidant performance of the catalyst. The catalyst is designed to balance low cost and high performance, and solve the key technical bottlenecks of low activity and easy oxidation deactivation of nickel-based catalysts in hydrogen fuel cell anode applications.

[0028] (2) The preparation method of the antioxidant nickel-based catalyst of the present invention is simple, economical, convenient to operate and easy to produce on a large scale, and has great potential application value in many industrial catalysts or other scientific fields.

[0029] (3) The antioxidant nickel-based catalyst prepared by the present invention has excellent antioxidant performance and a voltage window of more than 1V, which is significantly superior to existing Ni-based catalysts; it also has excellent anodic HOR catalytic activity, and the peak power density of the fuel cell is more than twice that of existing nickel-based catalysts. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 The images shown are the TEM, aberration-corrected HAADF, and XAS spectra in Embodiment 1 of the present invention, where a is the TEM image at a 10 nm scale, b is the TEM image at a 5 nm scale, c is the aberration-corrected HAADF image, and d is the XAS spectrum. Figure 2 This is an element distribution diagram from Embodiment 1 of the present invention; Figure 3 This is a CV loop test of Embodiment 1 of the present invention; Figure 4 This is a performance comparison chart of the anion exchange membrane fuel cell using a commercial PtRu / C catalyst in Example 2 of this invention; Figure 5 The LSV polarization curves of the commercial PtRu / C catalyst in Example 1 of this invention are shown. Figure 6 The figures show the polarization curves of the catalyst before and after accelerated cyclic aging of the commercial PtRu / C catalyst in Example 1 of the present invention, where a is the polarization curve of the catalyst before and after accelerated cyclic aging of the catalyst in Example 1, and b is the polarization curve of the commercial PtRu / C catalyst before and after accelerated cyclic aging. Detailed Implementation

[0032] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Specific conditions not specified in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Components whose manufacturers are not specified are all commercially available conventional products.

[0033] I. Antioxidant Nickel-Based Fuel Cell Anode Catalysts and Their Preparation Methods Example 1 An antioxidant nickel-based fuel cell anode catalyst and its preparation method thereof, comprising the following steps: (1) 2.92 g of ethylenediaminetetraacetic acid, 5 mL of triethylamine, and 5.82 g of nickel nitrate hexahydrate were dissolved in 0.6 L of DMF to form a mixed solution. After centrifugation, the precipitate was collected and dried. The precipitate was then heated to 600 °C and held at that temperature for 3 h under an Ar protective atmosphere. After cooling, the product was placed in 0.5 M dilute sulfuric acid and refluxed for 4 h to obtain graphite-coated Ni particles, labeled as Ni@NC.

[0034] (2) Mix 2 g of Ni@NC obtained in step (1) with 6 g of urea to obtain a mixture; place the mixture in a tube furnace and heat it to 300°C under an Ar atmosphere and keep it for 3 h. After cooling, wash with 3 L of anhydrous ethanol, collect the product by centrifugation, and obtain nitrogen-modified graphite-coated Ni particles, labeled as N-Ni@NC.

[0035] (3) 2 g of N-Ni@NC obtained in step (2) was dispersed in 500 mL of ethanol by ultrasonication and stirring, 40 mg of ruthenium trichloride was added, and the mixture was heated for ion adsorption. After adsorption, the mixture was repeatedly washed with no less than 5 L of anhydrous ethanol, filtered to obtain a precipitate, dried in an oven at 60 °C overnight, and then heat-treated at 500 °C for 3 h under an Ar atmosphere to obtain ruthenium-loaded nitrogen-modified graphite-coated Ni particles, labeled as Ru-N-Ni@NC.

[0036] Example 2 An antioxidant nickel-based fuel cell anode catalyst and its preparation method differ from Example 1 in that, in step (3), 1 g of N-Ni@NC obtained in step (2) is dispersed in 500 mL of ethanol by ultrasonication and stirring, and 200 mg of ruthenium trichloride is added to obtain a mixture. The mixture is heated at 50°C to remove the solvent, and then placed in a tube furnace and heated to 220°C under Ar atmosphere and held for 6 h. After cooling, it is washed with a large amount of ethanol / water mixture, filtered to obtain a precipitate, and placed in a 60°C oven to dry overnight. Then, it is heat-treated at 600°C under Ar atmosphere for 5 h to obtain ruthenium-loaded nitrogen-modified graphite-coated Ni particles, labeled as Ru-N-Ni@NC. Other preparation steps (1) and (2) are the same as in Example 1.

[0037] Example 3 An antioxidant nickel-based fuel cell anode catalyst and its preparation method are disclosed. The difference from Example 1 is that step (2) is omitted. In step (3), 1 g of Ni@NC obtained in step (1) is dispersed in 500 mL of ethanol by ultrasonication and stirring, and 50 mg of potassium tetrachloropalladate is added. Ion adsorption is then performed by heating. After adsorption, the precipitate is repeatedly washed with at least 5 L of anhydrous ethanol, filtered, and dried in a 60°C oven overnight. Then, it is heat-treated at 300°C for 3 h under an Ar atmosphere to obtain palladium-loaded graphite-coated Ni particles, labeled as Pd-Ni@NC.

[0038] Example 4 An antioxidant nickel-based fuel cell anode catalyst and its preparation method thereof, comprising the following steps: (1) 4 g of nickel chloride and 2 g of ammonium molybdate were placed in a mortar, and 6 g of melamine and 0.5 g of urea were added. The mixture was thoroughly ground and mixed to obtain a final product. The mixture was heated to 800 °C in a 10% H2 / Ar atmosphere and held for 2 h. After cooling, it was placed in 0.5 M dilute sulfuric acid and refluxed for 4 h to obtain graphite-coated nickel-molybdenum alloy nanoparticles, labeled as NiMo@NC.

[0039] (2) Mix 1 g of NiMo@NC obtained in step (1) with 100 mL of ethanol solution containing 40 mg of ruthenium trichloride, and stir continuously at 60 °C until the solvent is completely evaporated. Heat-treat the dried product at 700 °C for 3 h under Ar atmosphere to obtain nickel-molybdenum alloy nanoparticles coated with a graphite layer loaded with ruthenium, labeled as Ru-NiMo@NC.

[0040] Example 5 An antioxidant nickel-based fuel cell anode catalyst and its preparation method are disclosed. Unlike Example 4, in step (1), the prepared NiMo@NC is subjected to sulfur modification as step (2). The specific modification method is as follows: Step (2): 2 g of NiMo@NC obtained in step (1) was physically mixed with 5 g of sulfur powder to obtain a mixture; the mixture was placed in a tube furnace and heated to 220°C under an Ar atmosphere and held for 3 h. After cooling, it was washed with 3 L of carbon disulfide, and the product was collected by vacuum filtration to obtain sulfur-modified graphite-coated nickel-molybdenum alloy nanoparticles, labeled as S-NiMo@NC.

[0041] In step (3), 1 g of S-NiMo@NC obtained in step (2) was mixed with 100 mL of ethanol solution containing 40 mg of ruthenium trichloride, and stirred continuously until the solvent was completely evaporated. The dried product was heat-treated at 700 °C for 3 h under an Ar atmosphere to obtain ruthenium-loaded sulfur-modified graphite-coated nickel-molybdenum alloy nanoparticles, labeled as Ru-S-NiMo@NC.

[0042] Comparative Example 1 Unlike Example 1, steps (2) and (3) are omitted, and only step (1) is performed. The specific preparation process is as follows: 2.92 g of ethylenediaminetetraacetic acid, 5 mL of triethylamine, and 5.82 g of nickel nitrate hexahydrate were dissolved sequentially in 0.6 L of DMF to form a mixed solution. After centrifugation, the precipitate was collected, dried, and then heated to 600 °C under an Ar protective atmosphere and held for 3 h. After cooling, the product was placed in 0.5 M dilute sulfuric acid and refluxed for 4 h to obtain graphite-coated Ni particles, labeled Ni@NC.

[0043] Comparative Example 2 Unlike Example 4, step (2) is omitted, and only step (1) is performed. The specific preparation process is as follows: 4 g of nickel chloride and 2 g of ammonium molybdate were placed in a mortar, and 6 g of melamine and 0.5 g of urea were added. The mixture was thoroughly ground and mixed to obtain a final product. The mixture was heated to 800 °C in a 10% H2 / Ar atmosphere and held at that temperature for 2 h. After cooling, it was placed in 0.5 M dilute sulfuric acid and refluxed for 4 h to obtain graphite-coated nickel-molybdenum alloy nanoparticles, labeled NiMo@NC.

[0044] Comparative Example 3 Unlike Example 1, step (3) is omitted, and only steps (1) and (2) are performed. The specific preparation process is as follows: An antioxidant nickel-based fuel cell anode catalyst and its preparation method thereof, comprising the following steps: (1) 2.92 g of ethylenediaminetetraacetic acid, 5 mL of triethylamine, and 5.82 g of nickel nitrate hexahydrate were dissolved in 0.6 LDM to form a mixed solution. After centrifugation, the precipitate was collected and dried. Then, it was heated to 600 °C and held for 3 h under an Ar protective atmosphere. After cooling, the product was placed in 0.5 M dilute sulfuric acid and refluxed for 4 h to obtain graphite-coated Ni particles, labeled as Ni@NC.

[0045] (2) Mix 2 g of Ni@NC obtained in step (1) with 6 g of urea to obtain a mixture; place the mixture in a tube furnace and heat it to 300°C under an Ar atmosphere and keep it for 3 h. After cooling, wash with 3 L of anhydrous ethanol, collect the product by centrifugation, and obtain nitrogen-modified graphite-coated Ni particles, labeled as N-Ni@NC.

[0046] Comparative Example 4 Unlike Example 5, step (3) is omitted. The specific preparation process is as follows: (1) 4 g of nickel chloride and 2 g of ammonium molybdate were placed in a mortar, and 6 g of melamine and 0.5 g of urea were added. The mixture was thoroughly ground and mixed to obtain a mixture. The mixture was heated to 800 °C in a 10% hydrogen-argon mixture atmosphere and held at that temperature for 2 h. After cooling, the catalyst was placed in 0.5 M dilute sulfuric acid and refluxed for 4 h to obtain graphite-coated nickel-molybdenum alloy nanoparticles, labeled as NiMo@NC.

[0047] (2) 2 g of NiMo@NC obtained in step (1) was physically mixed with 5 g of sulfur powder to obtain a mixture; the mixture was placed in a tube furnace and heated to 220°C under Ar atmosphere and held for 3 h. After cooling, it was washed with 3 L of carbon disulfide, and the product was collected by vacuum filtration to obtain sulfur-modified graphite-coated nickel-molybdenum alloy nanoparticles, labeled as S-NiMo@NC.

[0048] Reference example Commercial PtRu / C catalyst (Pt content 30 wt%, Ru content 10 wt%, carbon support content 60 wt%).

[0049] II. Performance Characterization 1. Performance characterization of antioxidant nickel-based fuel cell anode catalysts Figure 1 The images shown are the TEM, aberration-corrected HAADF, and XAS spectra of Ru-Ni@NC in Example 1, where a is the TEM image at a 100 nm scale, b is the TEM image at a 10 nm scale, c is the aberration-corrected HAADF image, and d is the XAS spectrum.

[0050] Depend on Figure 1 The TEM images show that nickel metal nanoparticles are uniformly coated with a graphite layer, and the graphite ( Figure 1 As shown in a and b). The HAADF images clearly show that nickel nanoparticles (NPs) are distributed inside the graphite layer, while single metal atoms (SAs) are distributed on the outer layer of the graphite layer. Figure 1 (As shown in c). According to the XAS spectrum, Ru-N-Ni@NC, compared with Ru foil and RuO2, has significantly different peaks. The absence of metallic Ru-Ru bonds and oxidized Ru-O bonds indicates that it exhibits a single-atom dispersion state, mainly in the form of Ru-N.

[0051] Figure 2 This is an elemental distribution diagram of Ru-N-Ni@NC in Embodiment 1 of the present invention. Figure 2It can be seen that Ni, Ru, N, and C are relatively uniformly dispersed, and the secondary metals do not show any local enrichment signals, exhibiting a diffuse distribution, indicating that their distribution is very uniform.

[0052] 2. Catalytic activity test: The test method for CV cycle testing is as follows: the catalyst is coated on a glassy carbon electrode, and data from 0 to 1.2 V are collected using cyclic voltammetry in 0.1 M KOH.

[0053] Test method for the performance of anion exchange membrane fuel cells: First, the catalyst is sprayed onto the treated anion exchange membrane using the CCM process, and then the membrane electrode assembly is prepared by hot pressing carbon paper on both sides. The membrane electrode assembly is then tested at 1 A / cm. 2 Activation was performed at the current density for 2 hours. Test parameters: temperature 75℃, humidity 100% RH, anolyte H2 flow rate 300 mL·min. -1 Cathode O2 flow rate 300 mL·min -1 .

[0054] The test results are shown in Table 1.

[0055] Table 1 Test Results

[0056] In Table 1, " / " indicates that the sample is not included or has not been detected.

[0057] As shown in Table 1, the catalyst prepared in Example 1 exhibited good antioxidant properties of Ni during electrochemical testing, with a voltage window exceeding 1 V. The Ru-Ni@NC prepared in Example 1 demonstrated excellent catalytic activity in anion exchange membrane fuel cell testing, requiring only 1 μg / cm³ of Ru. 2 At that time, the peak power density (PPD) can reach 1.2 W / cm². 2 Example 2 increased the content of the second metal through modification, achieving a PPD as high as 1.9 W / cm³. 2 Example 3 further investigated the performance curves of other binary metals, achieving a noble metal utilization rate as high as 466 W / mg. Pd Compared to Example 5, Example 4, after modification with S, showed further improvement in the performance of its membrane electrode, increasing from 1.3 to 1.5 W / cm². 2 The LSV curve tests of the half-cells in Comparative Examples 1-4 showed almost no activity, and the fuel cell performance was far lower than that of the examples with the introduction of a second metal. Commercial PtRu / C can also achieve 1.7 W / cm² by increasing the loading of the precious metal. 2 It has good performance, but the amount of precious metals used is high and the utilization rate is low, only 22.3 W / mg. PtRu The cost is relatively high.

[0058] Figure 3 The image shows the CV cycle test diagram for Example 1 (Ru-N-Ni@NC). Figure 3 This indicates that the catalyst does not have a significant signal peak indicating nickel oxidation.

[0059] Figure 4 This is a performance comparison graph of the anion exchange membrane fuel cell from Example 2 (Ru-N-Ni@NC) and a commercial PtRu / C catalyst. (Source: [Insert graph here]) Figure 4 It can be seen that the peak power density (PPD) of Example 2 can reach 1.9 W / cm². 2 Beyond a business catalyst.

[0060] Figure 5 The LSV polarization curves are for Example 1 (Ru-N-Ni@NC) and a commercial Ru / C catalyst. The commercial Ru / C catalyst shows a rapid decrease in cathode current at a voltage of 0.15 V, while the current density of Example 1 does not decrease significantly as the voltage increases to 1 V.

[0061] Figure 6 The figures show the polarization curves of the catalysts in Example 1 (Ru-N-Ni@NC) and the commercial PtRu / C catalyst before and after accelerated degradation testing (ADT), where a is the polarization curve of the catalyst in Example 1 before and after accelerated degradation testing, and b is the polarization curve of the commercial PtRu / C catalyst before and after accelerated degradation testing.

[0062] Depend on Figure 6 It can be seen that, compared with the current commercial anode catalyst Example 1, it has better stability at high oxidation potential, indicating that it has stronger antioxidant capacity.

[0063] In addition, the catalyst cost of Example 2 (Ru-N-Ni@NC) of the present invention is significantly lower than that of catalysts in the same industry, with a cost of only $1.07 per 100 kW power output. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nickel-based antioxidant catalyst, characterized in that, It has a core-shell structure, including nickel-based nanoparticles and a graphite layer coating the surface of the nickel-based nanoparticles; the graphite layer is loaded with a second metal site.

2. The nickel-based antioxidant catalyst according to claim 1, characterized in that, The nickel-based nanoparticles are one of nickel metal nanoparticles and nickel alloy nanoparticles; The nickel alloy nanoparticles comprise a nickel matrix and a first metal, wherein the first metal is one or more of Fe, Co, Mn, Cu, Ru, Pd, Ir, Mo, and W; and the first metal accounts for 1.0 wt%-80 wt% of the mass of the nickel alloy nanoparticles.

3. The nickel-based antioxidant catalyst according to claim 1, characterized in that, The number of graphite layers is 1-4; The second metal is one or more of the following metal single atoms or nanoclusters: Pt, Ru, Pd, Mo, Ir, Fe, Co, and Ni. The second metal accounts for 0.1 wt%-10 wt% of the total mass of the catalyst, preferably 1.0 wt%-2.0 wt% of the total mass of the catalyst.

4. The nickel-based antioxidant catalyst according to claim 1, characterized in that, The graphite layer also contains dopants, which are one or more of elemental or compound forms of S, P, Se and N; the dopants account for 1.0 wt% to 20 wt% of the mass of the graphite layer.

5. A method for preparing a nickel-based antioxidant catalyst according to any one of claims 1-4, characterized in that, Includes the following steps: A nickel-based catalyst coated with a graphite layer was prepared by pyrolysis of a mixture of nickel and carbon sources. The nickel-based catalyst coated with graphite layer is mixed with a second metal source and then subjected to heat treatment to obtain a nickel-based antioxidant catalyst.

6. The method for preparing the nickel-based antioxidant catalyst according to claim 5, characterized in that, The mass ratio of the nickel source to the carbon source is 1:(0.5-10), preferably 1:(2-4); The pyrolysis temperature is 300-1000℃, and the pyrolysis time is 1-5h; preferably, the temperature is 400-600℃, and the pyrolysis time is 2-3h. The nickel source is one or more of nickel nitrate, nickel chloride, nickel sulfate, and nickel acetylacetone; The carbon source is one or more of the following: ethylenediaminetetraacetic acid, tetrasodium ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, bipyridine, imidazole, melamine, dicyandiamide, cyanamide, urea, hexamethylenetetramine, thiol, oleic acid, stearic acid, oleylamine, sodium oleate, 4-aminocatechol, 2-amino-1,3-benzene, 4-amino-1,3-benzene, and 3,5-diaminophenol. Preferably, the nickel source is one of nickel nitrate and nickel chloride; The carbon source is ethylenediaminetetraacetic acid.

7. The method for preparing the nickel-based antioxidant catalyst according to claim 5, characterized in that, The second metal source accounts for 0.1 wt%-10 wt% of the total mass of the catalyst; preferably, the second metal accounts for 1.0 wt%-2.0 wt% of the total mass of the catalyst. The heat treatment temperature is 200-1000℃ and the heat treatment time is 1-6 h; preferably, the heat treatment temperature is 300-700℃ and the heat treatment time is 3-5 h. The second metal source is one or more of Pt, Ru, Pd, Mo, Ir, Fe, Co, and Ni; Preferably, the second metal source is one of Ru and Pd.

8. The method for preparing the nickel-based antioxidant catalyst according to claim 5, characterized in that, The preparation of graphite-coated nickel-based catalysts also includes adding a first metal source, mixing the nickel source, the first metal source, and the carbon source, and then performing pyrolysis; the first metal source is one or more of Fe, Co, Mn, Cu, Ru, Pd, Ir, Mo, and W; The first metal accounts for 1.0 wt%-80 wt% of the mass of the nickel alloy nanoparticles. Alternatively, it may also include modifying the graphite-coated nickel-based catalyst, wherein the modification method involves mixing the graphite-coated nickel-based catalyst with a dopant and then subjecting it to a heating modification treatment. The dopant is one or more of elemental or compound forms of S, P, Se, and N; the doping amount of the doped atoms accounts for 1wt%-20wt% of the graphite layer. The heating modification treatment is performed at a temperature of 200-300℃ for 2-3 hours.

9. The application of the nickel-based antioxidant catalyst according to any one of claims 1-4 in the anode of a fuel cell.

10. A fuel cell anode, characterized in that, Contains the nickel-based antioxidant catalyst according to any one of claims 1-4.

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