Preparation method of bimodal mesoporous carbon / metal oxide loaded noble metal catalyst with graded pore channels

Abstract

The invention relates to the technical field of catalyst preparation, in particular to a preparation method of a bimodal mesoporous carbon / metal oxide loaded noble metal catalyst with graded pore channels. The preparation method comprises the following steps: inducing ordered polycondensation self-assembly of a carbon source and a silicon source by a nonionic surfactant under an acidic condition, and coordinating with a polymer under the action of a cationic surfactant to form a metal-organic precursor through polymerization-induced self-assembly; a continuous mesoporous carbon skeleton is constructed through high-temperature calcination and carbonization, and a limited metal precursor is converted into a metal oxide phase with an independent mesoporous structure in situ in the carbon skeleton, so that hierarchical pore structures which are different in pore size and are communicated with one another are successfully constructed. The unique double-mesoporous structure provides abundant anchoring points for precious metal, so that the finally prepared catalyst shows excellent electrochemical activity and stability in a fuel cell anode CO / H2 atmosphere, and shows a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and specifically to a method for preparing a noble metal catalyst supported on a dual mesoporous carbon / metal oxide with hierarchical channels. Background Technology

[0002] With the accelerated commercialization of proton exchange membrane fuel cells, their efficient and clean energy conversion characteristics have attracted much attention. However, in practical applications, reformed hydrogen is usually used as fuel gas, which inevitably contains trace amounts of carbon monoxide (CO). Even at concentrations as low as 10 ppm, CO can be strongly adsorbed on the surface of platinum-based anode catalysts, occupying active sites and causing severe catalyst "poisoning." This significantly reduces battery performance and operating life, becoming one of the key technical bottlenecks restricting its large-scale application.

[0003] Traditional strategies for combating CO poisoning primarily involve introducing a second metal component (such as ruthenium or tin) to form platinum-based alloy catalysts, utilizing their electronic effects or bifunctional mechanisms to promote CO oxidation and removal. However, these noble metal alloy catalysts still face challenges such as high cost, metal dissolution during long-term operation, and component segregation, leading to a decline in their anti-poisoning performance. Therefore, developing novel anodic catalyst systems that are low-cost, highly stable, and possess excellent CO poisoning resistance has become a current research frontier and focus.

[0004] In recent years, non-precious metal catalysts and modified supports have attracted attention due to their potential in resisting CO poisoning. Compared with traditional carbon supports, some metal oxides (such as TiO2, WO3, CeO2, etc.) can effectively regulate the electronic state of platinum atoms on the surface through strong metal-support interactions, thereby weakening the adsorption intensity of CO. More importantly, some oxides with oxygen storage and release capabilities (such as CeO2) can provide active oxygen species at the interface, promoting the oxidation of adsorbed CO to CO2 at lower potentials, thus continuously cleaning platinum active sites. However, single metal oxide supports often face problems such as poor conductivity and limited specific surface area, making it difficult to achieve both high activity and strong anti-poisoning properties simultaneously. Controllable mesoporous carbon-supported metal oxide composites, due to their unique confinement effect and structural designability, provide a new approach to solving this contradiction. This material system can utilize the high conductivity and mass transfer advantages of mesoporous carbon, and achieve a synergistic improvement in CO tolerance and catalytic activity through electronic regulation of the metal oxide-platinum interface within the confined space.

[0005] Therefore, how to construct composite carrier-supported catalysts with high activity, strong resistance to poisoning, and long lifespan by precisely designing mesoporous structures and confinement effects has become a key technological bottleneck that urgently needs to be overcome to promote the practical application of fuel cells. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose a method for preparing a noble metal catalyst supported on a dual mesoporous carbon / metal oxide with hierarchical channels, so as to solve the problems of poor CO poisoning resistance, low utilization of active sites, insufficient mass transfer efficiency and poor stability of active components of existing noble metal catalysts under CO / H2 atmosphere at the anode of fuel cells.

[0007] To achieve the above objectives, this invention provides a method for preparing a noble metal catalyst supported on a dual mesoporous carbon / metal oxide with hierarchical channels, comprising the following steps:

[0008] (1) Preparation of mesoporous carbon precursor sol: Nonionic surfactant, dilute hydrochloric acid, carbon source and surface pore-forming agent are mixed and stirred in an organic solvent to form mesoporous carbon precursor sol;

[0009] (2) Preparation of metal-organic precursor solution: Mix and stir the metal salt, organic ligand, cationic surfactant and organic solvent to form metal-organic precursor solution;

[0010] (3) Preparation of dual mesoporous carbon-metal oxide materials with hierarchical channels: The metal-organic precursor solution is added dropwise to the mesoporous carbon precursor sol for microwave-assisted synthesis. After the microwave is finished, the mixture is allowed to stand for aging to form an organic-inorganic composite gel. The composite gel is transferred to an inert atmosphere for staged sintering, followed by alkali washing and freeze drying to obtain dual mesoporous carbon-metal oxide materials with hierarchical channels.

[0011] (4) Mix the bi-mesoporous carbon-metal oxide material with hierarchical channels with a noble metal source and an alcohol solvent, and perform microwave-assisted synthesis. After centrifugation, washing and drying, a bi-mesoporous carbon / metal oxide supported noble metal catalyst with hierarchical channels is obtained.

[0012] Preferably, the nonionic surfactant mentioned in step (1) is one of P123, F127, P65, F108, CTAB, and PMMA.

[0013] Preferably, the surface pore-forming agent in step (1) is one of TEOS, TMOS, APTES, MTES, and sodium silicate.

[0014] Preferably, the carbon source in step (1) is one of sucrose, furfuryl alcohol, polyacrylonitrile, and polyvinyl alcohol.

[0015] Preferably, the molar ratio of the nonionic surfactant, surface pore-forming agent, carbon source and dilute hydrochloric acid in step (1) is 1:20-100:20-120:40-80.

[0016] Preferably, the organic solvent in step (1) is one of methanol, ethanol, isopropanol, ethylene glycol, and dimethylformamide.

[0017] Preferably, the molar concentration of the dilute hydrochloric acid in step (1) is 2 mol / L.

[0018] Preferably, the stirring time in step (1) is 6-24h and the stirring temperature is 30-50℃.

[0019] Preferably, the metal salt in step (2) is one of nitrate, chloride, or phosphate, and exists in the form of a hydrate.

[0020] Preferably, the organic ligand in step (2) is one of 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-nitroimidazole, and benzimidazole.

[0021] Preferably, the organic solvent in step (2) is one of methanol, ethanol, isopropanol, ethylene glycol, and dimethylformamide.

[0022] Preferably, the cationic surfactant in step (2) is hexadecyltrimethylammonium bromide.

[0023] Preferably, the molar ratio of the metal salt, organic ligand, and cationic surfactant in step (2) is 1:2-10:5-20:.

[0024] Preferably, the stirring time in step (2) is 6-24h and the stirring temperature is 30-50℃.

[0025] Preferably, the molar ratio of the cationic surfactant in the metal-organic precursor solution and the nonionic surfactant in the mesoporous carbon precursor sol in step (3) is 1:10-20.

[0026] Preferably, the microwave-assisted synthesis in step (3) is performed at a temperature of 50-100℃, a time of 10-60 min, and a power of 100-500 W.

[0027] Preferably, the aging time in step (3) is 6-12 hours.

[0028] Preferably, the inert atmosphere in step (3) is a nitrogen or argon atmosphere.

[0029] Preferably, the specific process of the staged sintering in step (3) is as follows: sintering for 1-2 hours after heating to 100-150℃ at 1-5℃ / min, sintering for 1-3 hours after heating to 350-400℃ at 1-5℃ / min, and sintering for 2-4 hours after heating to 750-850℃ at 1-5℃ / min.

[0030] Preferably, the weight ratio of the dual mesoporous carbon-metal oxide material with hierarchical channels, the noble metal precursor, and the alcohol solvent in step (4) is 1:0.5-2.5:20-200.

[0031] Preferably, the temperature of the microwave synthesis reaction in step (4) is 140-200℃, the time of the microwave synthesis reaction is 5-120min, and the power is 50-500W.

[0032] Preferably, the precious metal source in step (4) is any one of Pt, Ru, and Pd hydrates.

[0033] Preferably, the alcohol solvent in step (4) is ethylene glycol.

[0034] The beneficial effects of this invention are:

[0035] This invention ingeniously utilizes the synergistic effect of nonionic and cationic surfactants to induce the self-assembly of carbon sources and metal precursors, thereby constructing two hierarchical mesoporous structures in stages, independently and interconnectedly: during high-temperature sintering, the nonionic surfactant and polymer carbonize to form a continuous mesoporous carbon skeleton (primary mesoporous structure), while the confined metal precursor is transformed in situ into a metal oxide phase with an independent mesoporous structure (secondary mesoporous structure). This unique dual mesoporous structure not only achieves precise construction from micropores to different mesoporous sizes, greatly increasing the specific surface area and exposing more active sites, but also facilitates rapid mass transfer between reactants and products, effectively reduces the loading of internal particles, and provides efficient reactant contact and electron transfer pathways, thus maintaining catalytic activity and structural stability for a long time.

[0036] This invention uses metal oxides as a partial support material. Through the metal-support interaction formed by the oxides and noble metals, as well as the interfacial electronic regulation within the confined space, the bonding strength between noble metals and CO can be effectively weakened, significantly improving the catalyst's resistance to CO poisoning and stability. It exhibits excellent electrochemical activity and stability at the anode of fuel cells under a CO / H2 atmosphere, and has broad application prospects. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0038] Figure 1 The polarization curve of a fuel cell using a platinum catalyst supported on a bimesoporous carbon / tin metal oxide with hierarchical channels prepared in Example 1 as the anode catalyst.

[0039] Figure 2The polarization curve of a fuel cell using a platinum catalyst supported on a bimesoporous carbon / tin metal oxide with hierarchical channels, prepared in Example 2, as the anode catalyst.

[0040] Figure 3 The polarization curve of a fuel cell using a platinum-supported carbon / tin metal oxide catalyst with hierarchical channels prepared in Example 3 as the anode catalyst.

[0041] Figure 4 The polarization curve of the fuel cell using the mesoporous carbon / tin metal oxide supported platinum catalyst with a single channel prepared in Comparative Example 1 as the anode catalyst.

[0042] Figure 5 The polarization curve of the fuel cell using the carbon / mesoporous tin metal oxide supported platinum catalyst with a single channel prepared in Comparative Example 2 as the anode catalyst.

[0043] Figure 6 Polarization curves of fuel cells using H2 as the anode gas, based on the catalysts prepared in Examples 1, 2, 3 and Comparative Examples 1, 2 as the anode catalysts;

[0044] Figure 7 Polarization curves of fuel cells using the catalysts prepared in Examples 1, 2, 3 and Comparative Examples 1 and 2 as anode catalysts with 100 ppm CO / H2 as the anode gas.

[0045] Figure 8 The graph shows the CO stability test curve of the fuel cell using the dual mesoporous carbon / tin metal oxide supported platinum catalyst with hierarchical channels prepared in Example 2 as the anode catalyst. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0047] Example 1: A method for preparing a noble metal catalyst supported on a dual mesoporous carbon / metal oxide with hierarchical channels, the specific steps of which are as follows:

[0048] (1) Preparation of mesoporous carbon precursor sol: Nonionic surfactant P123, TEOS, furfuryl alcohol and 2 mol / L dilute hydrochloric acid were added to 50 mL of anhydrous ethanol in a molar ratio of 1:20:20:40 and stirred at 30 °C for 6 h to form a uniform mesoporous carbon precursor sol.

[0049] (2) Preparation of metal-organic precursor solution: Add tin tetrachloride pentahydrate, 2-methylimidazole and hexadecyltrimethylammonium bromide in a molar ratio of 1:2:10 to 50 mL of methanol and mix well. Stir at 30 °C for 6 h to form a stable metal-organic precursor solution.

[0050] (3) Preparation of dual mesoporous carbon-metal oxide material with hierarchical channels: The metal-organic precursor solution was added dropwise to the mesoporous carbon precursor sol. The molar ratio of surfactant P123 and hexadecyltrimethylammonium bromide was 1:10. The dropwise addition time was 0.5h. Microwave-assisted synthesis was carried out at 50℃ and 100W for 5min. After microwave end, the mixture was allowed to stand for 6h to form an organic-inorganic composite gel. The composite gel was transferred to a nitrogen atmosphere and sintered at 1℃ / min to 100℃ for 1h. Then, it was sintered at 1℃ / min to 350℃ for 1h. Then, it was sintered at 1℃ / min to 750℃ for 2h. After natural cooling, it was washed with 1mol / L sodium hydroxide solution and then freeze-dried with liquid nitrogen for 24h to form a dual mesoporous carbon-metal oxide material with hierarchical channels.

[0051] (4) Add 1 part of a bi-mesoporous carbon-metal oxide material with hierarchical channels and 0.5 parts of chloroplatinic acid hexahydrate to 20 parts of ethylene glycol. Perform microwave-assisted synthesis at 140℃ and 50W for 5 min. After centrifugation and washing 4 times at 3000 rpm, the resulting solution is dried at 50℃ for 6 h to obtain the target product, a bi-mesoporous carbon / metal oxide supported noble metal catalyst with hierarchical channels.

[0052] Example 2: A method for preparing a noble metal catalyst supported on a dual mesoporous carbon / metal oxide with hierarchical channels, the specific steps of which are as follows:

[0053] (1) Preparation of mesoporous carbon precursor sol: Nonionic surfactant P123, TEOS, furfuryl alcohol and 2 mol / L dilute hydrochloric acid were added to anhydrous ethanol in a molar ratio of 1:60:7:60 and stirred at 40°C for 15 h to form a uniform mesoporous carbon precursor sol.

[0054] (2) Preparation of metal-organic precursor solution: Add tin tetrachloride pentahydrate, 2-methylimidazole and hexadecyltrimethylammonium bromide in a molar ratio of 1:6:15 to 50 mL of methanol and mix well. Stir at 40 °C for 15 h to form a stable metal-organic precursor solution.

[0055] (3) Preparation of dual mesoporous carbon-metal oxide material with hierarchical channels: The metal-organic precursor solution was added dropwise to the mesoporous carbon precursor sol. The molar ratio of surfactant P123 and hexadecyltrimethylammonium bromide was 1:15. The dropwise addition time was 2h. Microwave-assisted synthesis was carried out at 580℃ and 300W for 60min. After microwave end, the mixture was allowed to stand for 9h to form an organic-inorganic composite gel. The composite gel was transferred to a nitrogen atmosphere and sintered at 3℃ / min to 130℃ for 1.5h. Then, it was sintered at 3℃ / min to 380℃ for 2h. Then, it was sintered at 3℃ / min to 800℃ for 3h. After natural cooling, it was washed with 1mol / L sodium hydroxide solution and then freeze-dried with liquid nitrogen for 24h to form a dual mesoporous carbon-metal oxide material with hierarchical channels.

[0056] (4) Add 1 part of a bi-mesoporous carbon-metal oxide material with hierarchical channels and 1.5 parts of chloroplatinic acid hexahydrate to 110 parts of ethylene glycol. Microwave-assisted synthesis was carried out at 170℃ and 300W for 60 min. The resulting solution was centrifuged and washed 4 times at 4500 rpm and then dried at 55℃ for 15 h to obtain the target product, a bi-mesoporous carbon / metal oxide supported noble metal catalyst with hierarchical channels.

[0057] Example 3: A method for preparing a noble metal catalyst supported on a dual mesoporous carbon / metal oxide with hierarchical channels, the specific steps of which are as follows:

[0058] (1) Preparation of mesoporous carbon precursor sol: Nonionic surfactant P123, TEOS, furfuryl alcohol and 2 mol / L dilute hydrochloric acid were added to anhydrous ethanol in a molar ratio of 1:100:120:80 and stirred at 50°C for 24 h to form a uniform mesoporous carbon precursor sol.

[0059] (2) Preparation of metal-organic precursor solution: Add tin tetrachloride pentahydrate, 2-methylimidazole and hexadecyltrimethylammonium bromide in a molar ratio of 1:10:20 to 50 mL of methanol and mix well. Stir at 50 °C for 24 h to form a stable metal-organic precursor solution.

[0060] (3) Preparation of dual mesoporous carbon-metal oxide material with hierarchical channels: The metal-organic precursor solution was added dropwise to the mesoporous carbon precursor sol. The molar ratio of surfactant P123 and hexadecyltrimethylammonium bromide was 1:20. The dropwise addition time was 3h. Microwave-assisted synthesis was carried out at 100℃ and 500W for 120min. After the microwave was finished, the mixture was allowed to stand for 12h to form an organic-inorganic composite gel. The composite gel was transferred to a nitrogen atmosphere and sintered at 5℃ / min to 150℃ for 2h. Then, it was sintered at 5℃ / min to 400℃ for 3h. Then, it was sintered at 5℃ / min to 850℃ for 4h. After natural cooling, it was washed with 1mol / L sodium hydroxide solution and then freeze-dried with liquid nitrogen for 24h to form a dual mesoporous carbon-metal oxide material with hierarchical channels.

[0061] (4) Add 1 part of a bi-mesoporous carbon-metal oxide material with hierarchical channels and 2.5 parts of chloroplatinic acid hexahydrate to 200 parts of ethylene glycol. Microwave-assisted synthesis was carried out at 200℃ and 500W for 120 min. The resulting solution was centrifuged and washed 4 times at 6000 rpm and then dried at 65℃ for 24 h to obtain the target product, a bi-mesoporous carbon / metal oxide supported noble metal catalyst with hierarchical channels.

[0062] Comparative Example 1: A method for preparing a mesoporous carbon / metal oxide supported noble metal catalyst with a single pore, the specific steps of which are as follows:

[0063] (1) Preparation of mesoporous carbon precursor sol: Nonionic surfactant P123, TEOS, furfuryl alcohol and 2 mol / L dilute hydrochloric acid were added to 50 mL of anhydrous ethanol in a molar ratio of 1:20:20:40 and stirred at 30 °C for 6 h to form a uniform mesoporous carbon precursor sol.

[0064] (2) Preparation of metal-organic precursor solution: Add tin tetrachloride pentahydrate and 2-methylimidazole to 50 mL of methanol at a molar ratio of 1:2 and mix well. Stir at 30 °C for 6 h to form a stable metal-organic precursor solution.

[0065] (3) Preparation of mesoporous carbon-metal oxide material with single channel: The metal-organic precursor solution was added dropwise to the mesoporous carbon precursor sol for 0.5 h. Microwave-assisted synthesis was carried out at 50 °C and 100 W for 5 min. After microwave treatment, the mixture was allowed to stand for 6 h to form an organic-inorganic composite gel. The composite gel was transferred to a nitrogen atmosphere and sintered at 1 °C / min to 100 °C for 1 h. Then, the temperature was increased to 350 °C at 1 °C / min and sintered for 1 h. Then, the temperature was increased to 750 °C at 1 °C / min and sintered for 2 h. After natural cooling, the mixture was washed with 1 mol / L sodium hydroxide solution and then freeze-dried with liquid nitrogen for 24 h to form a mesoporous carbon-metal oxide material with single channel.

[0066] (4) Add 1 part of mesoporous carbon-metal oxide material with a single channel and 0.5 parts of chloroplatinic acid hexahydrate to 20 parts of ethylene glycol. Microwave-assisted synthesis is carried out at 140℃ and 50W for 5 min. The resulting solution is centrifuged and washed 4 times at 3000 rpm and then dried at 50℃ for 6 h to obtain a noble metal catalyst supported on mesoporous carbon / metal oxide with a single channel.

[0067] Comparative Example 2: A method for preparing a noble metal catalyst supported on a carbon / mesoporous metal oxide with a single pore, the specific steps of which are as follows:

[0068] (1) Preparation of carbon precursor sol: TEOS, furfuryl alcohol and 2 mol / L dilute hydrochloric acid were added to 50 mL of anhydrous ethanol in a molar ratio of 1:1:2 and stirred at 30 °C for 6 h to form a homogeneous carbon precursor sol.

[0069] (2) Preparation of metal-organic precursor solution: Add tin tetrachloride pentahydrate, 2-methylimidazole and hexadecyltrimethylammonium bromide in a molar ratio of 1:2:10 to 50 mL of methanol and mix well. Stir at 30 °C for 6 h to form a stable metal-organic precursor solution.

[0070] (3) Preparation of carbon-mesoporous metal oxide material with single channel: The metal-organic precursor solution was added dropwise to the carbon precursor sol for 0.5 h. Microwave-assisted synthesis was carried out at 50 °C and 100 W for 5 min. After microwave treatment, the mixture was allowed to stand for 6 h to form an organic-inorganic composite gel. The composite gel was transferred to a nitrogen atmosphere and sintered at 1 °C / min to 100 °C for 1 h. Then, the temperature was increased to 350 °C at 1 °C / min and sintered for 1 h. Then, the temperature was increased to 750 °C at 1 °C / min and sintered for 2 h. After natural cooling, the mixture was washed with 1 mol / L sodium hydroxide solution and then freeze-dried with liquid nitrogen for 24 h to form a carbon-mesoporous metal oxide material with single channel.

[0071] (4) Add 1 part of carbon-mesoporous metal oxide material with a single channel and 0.5 parts of chloroplatinic acid hexahydrate to 20 parts of ethylene glycol. Microwave-assisted synthesis is carried out at 140℃ and 50W for 5 min. The resulting solution is centrifuged and washed 4 times at 3000 rpm and then dried at 50℃ for 6 h to obtain a carbon / mesoporous metal oxide supported noble metal catalyst with a single channel.

[0072] Performance testing

[0073] Preparation of anode catalyst ink: 100 mg of catalyst samples obtained from each example and comparative example were dispersed in a mixed solution of water and isopropanol (VDIW / Visoprobanol = 1:9), and then 5% wt of Nafion solution was added and subjected to ultrasonic shearing treatment for 1 h.

[0074] Preparation of cathode catalyst ink: 100 mg of commercial Pt / C catalyst was dispersed in a mixed solution of water and isopropanol (VDIW / Visoprobanol = 1:9), then 5 wt% Nafion solution was added and subjected to ultrasonic shearing for 1 h;

[0075] Then, the anode and cathode catalyst inks were applied to the proton exchange membrane using an ultrasonic sprayer, and carbon paper was pressed onto both sides of the membrane to serve as a gas diffusion layer (GDL). The anode Pt loading was 0.1 mg / cm³. 2 The cathode Pt loading is 0.3 mg / cm³. 2 The effective area of ​​the PEM fuel cell is 1 cm². 2 This forms a membrane electrode.

[0076] The prepared membrane electrode assembly was assembled using a fuel cell test fixture. The heating rod was set to 80°C to heat the fuel cell, and the temperature of the hydrothermal tank was set to 85°C. To ensure 100% gas humidity, the gas flow rates at both the anode and cathode were 200 mL / min. The fuel cell was activated by applying a cycle of stepped voltage using a fuel cell test bench. The polarization curve of the PEM fuel cell at 0.35V-Voc was recorded at 0.05V intervals. The change in current was recorded by applying a constant voltage of 0.4V to measure the catalyst stability.

[0077] When measuring the resistance to CO poisoning, 100 ppm CO / H2 was introduced into the anode, and the polarization curve of the PEM fuel cell at 0.35V-Voc was recorded at 0.05V intervals. The change in current was recorded by applying a constant voltage of 0.4V, thereby measuring the catalyst's resistance to CO poisoning. The test results are shown in the attached figure.

[0078] Data analysis: such as Figure 1The figure shows the polarization curves of a fuel cell using the hierarchical mesoporous carbon / tin metal oxide supported platinum catalyst prepared in Example 1 as the anode catalyst. It can be seen that the peak power density of the fuel cell based on the Pt@SnO2+C catalyst at 100ppm CO / H2 is 1.38 W·cm⁻¹. -2 It is clear that the performance of Pt / C has been completely lost because CO has occupied all the active sites of Pt. In addition, the peak power density of the fuel cell based on Pt@SnO2+C catalyst decreased by 37%.

[0079] like Figure 2 The figure shows the polarization curves of the fuel cell using the hierarchical mesoporous carbon / tin metal oxide supported platinum catalyst prepared in Example 2 as the anode catalyst. It can be seen that the peak power density of the fuel cell based on the Pt@SnO2+C catalyst at 100ppm CO / H2 is 1.59 W·cm⁻¹. -2 It is clear that the performance of Pt / C has been completely lost because CO has occupied all the active sites of Pt. In addition, the peak power density of the fuel cell based on Pt@SnO2+C catalyst decreased by 23%.

[0080] like Figure 3 The figure shows the polarization curves of the fuel cell using the hierarchical mesoporous carbon / tin metal oxide supported platinum catalyst prepared in Example 3 as the anode catalyst. It can be seen that the peak power density of the fuel cell based on the Pt@SnO2+C catalyst at 100ppm CO / H2 is 1.53 W·cm⁻¹. -2 It is clear that the performance of Pt / C has been completely lost because CO has occupied all the active sites of Pt. In addition, the peak power density of the fuel cell based on Pt@SnO2+C catalyst decreased by 18%.

[0081] like Figure 4 The figure shows the polarization curves of a fuel cell using the single-channel mesoporous carbon / tin metal oxide-supported platinum catalyst prepared in Comparative Example 1 as the anode catalyst. It can be seen that the peak power density of the fuel cell based on the Pt@SnO2+C catalyst at 100 ppm CO / H2 is 1.02 W·cm⁻¹. -2 It is clear that the performance of Pt / C has been completely lost because CO has occupied all the active sites of Pt / C. In addition, the peak power density of the fuel cell based on Pt@SnO2+C catalyst decreased by 34%.

[0082] like Figure 5The figure shows the polarization curves of the fuel cell using the single-channel carbon / mesoporous tin metal oxide supported platinum catalyst prepared in Comparative Example 2 as the anode catalyst. It can be seen that the peak power density of the fuel cell based on the Pt@SnO2+C catalyst at 100ppm CO / H2 is 0.64 W·cm⁻¹. -2 It is clear that the performance of Pt / C has been completely lost because CO has occupied all the active sites of Pt / C. In addition, the peak power density of the fuel cell based on Pt@SnO2+C catalyst decreased by 41%.

[0083] like Figure 6 The figure shows the polarization curves of fuel cells using the catalysts prepared in Examples 1, 2, and 3 and Comparative Examples 1 and 2 as anode catalysts under an H2 / O2 atmosphere. It can be seen that the peak power densities of the fuel cells based on Examples 1, 2, and 3 are 2.15 W·cm⁻¹, respectively. -2 2.04 W·cm -2 and 1.89 W·cm -2 The peak power densities of the fuel cells in Comparative Examples 1 and 2 are 1.61 W·cm³, respectively. -2 and 1.85 W·cm -2 Under pure H2 atmosphere as the anode gas, the examples all exhibited higher peak power densities than the comparative examples, demonstrating the advantages of hierarchical channels facilitating mass transfer and providing more active sites.

[0084] like Figure 7 The figure shows the polarization curves of fuel cells using the catalysts prepared in Examples 1, 2, 3 and Comparative Examples 1, 2 as anode catalysts under a 100 ppm CO-H2 / O2 atmosphere. It can be seen that the peak power densities of the fuel cells based on Examples 1, 2, and 3 reach 1.37 W·cm⁻¹, respectively. -2 1.53 W·cm -2 and 1.61 W·cm -2 The peak power densities of the fuel cells in Comparative Examples 1 and 2 are 1.00 W·cm³, respectively. -2 and 0.73 W·cm -2 Under a pure 100ppm CO-H2 atmosphere as the anode gas, the examples all exhibited peak power densities far exceeding those of the comparative example. The hierarchical channels not only facilitated mass transfer but also made it easier for the Pt active particles to interact with the metal oxide to form a metal carrier, thereby improving the CO resistance performance. Compared with the test in a pure H2 environment, the peak power density decay was also lower than that of the comparative example, demonstrating superior performance.

[0085] like Figure 8As shown, in order to further study the CO poisoning resistance of the fuel cell based on the hierarchical dual mesoporous carbon / tin metal oxide supported platinum catalyst prepared in Example 2 as the anode catalyst, the battery was able to operate stably for more than 130 minutes, which confirmed that the fuel cell with Pt@SnO2+C catalyst has a certain CO poisoning resistance.

[0086] In summary, the dual mesoporous structure with hierarchical channels of the present invention significantly outperforms the single-channel mesoporous structure in terms of peak power density under pure hydrogen and 100ppm CO conditions, and exhibits lower power decay. This has practical significance for the application of noble metal catalysts in the field of fuel cells.

[0087] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A method for preparing a noble metal catalyst supported on a bimesoporous carbon / metal oxide substrate with hierarchical channels, characterized in that, Includes the following steps: (1) Mix and stir nonionic surfactant, dilute hydrochloric acid, carbon source and surface pore-forming agent in organic solvent to form mesoporous carbon precursor sol; (2) Mix and stir the metal salt, organic ligand, cationic surfactant and organic solvent to form a metal-organic precursor solution; (3) The metal-organic precursor solution was added dropwise to the mesoporous carbon precursor sol for microwave-assisted synthesis. After aging, an organic-inorganic composite gel was formed and sintered in stages in an inert atmosphere to obtain a dual mesoporous carbon-metal oxide material with hierarchical channels. (4) Mix the bi-mesoporous carbon-metal oxide material with hierarchical channels with a noble metal source and an alcohol solvent, and perform microwave-assisted synthesis to form a bi-mesoporous carbon / metal oxide supported noble metal catalyst with hierarchical channels.

2. The preparation method according to claim 1, characterized in that, The molar ratio of the nonionic surfactant, pore-forming agent, carbon source and dilute hydrochloric acid in step (1) is 1:20-100:20-120:40-80.

3. The preparation method according to claim 1, characterized in that, The nonionic surfactant mentioned in step (1) is one of P123, F127, P65, F108, CTAB, and PMMA; the surface pore-forming agent is one of TEOS, TMOS, APTES, MTES, and sodium silicate; the carbon source is one of sucrose, furfuryl alcohol, polyacrylonitrile, and polyvinyl alcohol; and the organic solvent is one of methanol, ethanol, isopropanol, ethylene glycol, and dimethylformamide.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the metal salt, organic ligand, and cationic surfactant is 1:2-10:5-20.

5. The preparation method according to claim 1, characterized in that, The metal salt mentioned in step (2) is one of nitrate, chloride, or phosphate, existing in the form of a hydrate; the organic ligand is one of 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-nitroimidazole, or benzimidazole; the organic solvent is one of methanol, ethanol, isopropanol, ethylene glycol, or dimethylformamide; and the cationic surfactant is hexadecyltrimethylammonium bromide.

6. The preparation method according to claim 1, characterized in that, The molar ratio of the cationic surfactant in the metal-organic precursor solution and the nonionic surfactant in the mesoporous carbon precursor sol in step (3) is 1:10-20.

7. The preparation method according to claim 1, characterized in that, The microwave-assisted synthesis in step (3) is performed at a temperature of 50-100℃, a time of 10-60 min, and a power of 100-500W.

8. The preparation method according to claim 1, characterized in that, The specific process of the staged sintering in step (3) is as follows: sintering for 1-2 hours after heating to 100-150℃ at 1-5℃ / min, sintering for 1-3 hours after heating to 350-400℃ at 1-5℃ / min, and sintering for 2-4 hours after heating to 750-850℃ at 1-5℃ / min.

9. The preparation method according to claim 1, characterized in that, In step (4), the weight ratio of the hierarchical pore dual mesoporous carbon-metal oxide material, the noble metal precursor, and the alcohol solvent is 1:0.5-2.5:20-200; the noble metal source is any one of Pt, Ru, and Pd hydrates.

10. The preparation method according to claim 1, characterized in that, The temperature of the microwave synthesis reaction in step (4) is 140-200℃, the time of the microwave synthesis reaction is 5-120min, and the power is 50-500W.

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