Preparation method of carbon-supported noble metal catalyst resistant to poisoning by sulfur-containing species
By preparing the M-PtN/C alloy catalyst, the problem of fuel cell catalysts being susceptible to sulfur poisoning is solved, the high durability and activity of the catalyst are improved, the purification process is simplified, and the cost is reduced.
Patent Information
- Application Number
- CN202310337277.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-31
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2043-03-31
AI Technical Summary
Existing fuel cell catalysts are susceptible to poisoning of sulfur-containing species, resulting in reduced performance or failure. The existing purification methods are complex and costly.
The preparation method of M-PtN/C alloy catalyst is adopted to synthesize disordered M-PtN/C alloy nanocrystals by solvothermal method, and atomic order is achieved through heat treatment to form a high-durability anti-toxic Pt-based catalyst.
It improves the catalyst's anti-sulfur poisoning ability, enhances the activity and stability of the catalyst, and reduces system complexity and cost.
Smart Images
Figure CN116364955B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for preparing a carbon-supported noble metal catalyst resistant to poisoning by sulfur-containing species. The catalyst is suitable for the development and preparation of noble metal catalysts in fields including chemical industry catalysis, fine chemical industry, hydrogen energy fuel cells, etc. Background Art
[0002] Fuel cells are a new energy system with high energy density, high efficiency, and environmental friendliness. Electrocatalysts, particularly cathode oxygen reduction reaction (ORR) catalysts, are key materials for fuel cell energy conversion. Currently, precious metals such as Pt-based catalysts are commonly used commercially. Sulfur poisoning of Pt-based catalysts is a significant issue in PEMFC applications. Research has shown that the main gaseous impurities that poison Pt are CO, H₂S, or SO₂. In PEMFCs, CO poisoning primarily affects the anode catalyst. CO adsorption at the cathode electrode is weak, with a desorption potential of approximately ~0.65 V. Therefore, at the normal operating potential of the PEMFC cathode (0.5-0.95 V), CO desorbs spontaneously during the cathode ORR process. However, the S lone pairs of sulfur-containing species, such as H₂S or SO₂, readily combine with Pt d-orbital electrons to form strongly adsorbed Pt-S bonds, which occupy a large number of active sites on the catalyst, leading to catalyst poisoning and even shutdown.
[0003] The current situation where industrial emissions from coal use contain sulfides will persist for a long time. The cathode of a fuel cell is actually a semi-open system where oxygen from the air acts as a fuel to directly participate in the electrochemical reaction. The air is inevitably mixed with industrial waste gas and automobile exhaust, especially in specific places such as parking lots, culverts, and tunnels. Its concentration can increase significantly, which can easily lead to catalyst poisoning and failure, causing serious degradation of battery performance or even permanent failure. If the fuel cell's intake air is treated from an engineering perspective by adding a purification device, not only will the cost increase, but the system will also become more complex. Therefore, it is very important to solve the problem of sulfur poisoning in automotive fuel cells from the material side. Summary of the Invention
[0004] The purpose of the present invention is to provide a method for preparing a carbon-supported noble metal catalyst resistant to poisoning by sulfur-containing species, mainly to solve the technical problem of catalyst resistance to poisoning by sulfur-containing species.
[0005] The basic idea of the technical solution adopted by the present invention is:
[0006] 1) Preparation of M-PtN / C (N=Co, Ni, Cu, etc.; M=Mo, W, Ce, Au, etc.) alloy catalysts.
[0007] By selecting appropriate concentrations and amounts of Pt metal salts, transition metal salts, and a small amount of other metal salt precursors, a solvothermal method was used to synthesize low-Pt disordered M-PtCo / C alloy nanocrystals with specific compositions and sizes. By varying the type of metal precursors and controlling parameters such as the solvent, reducing agent, surfactant, reaction time, and temperature in the reaction system, the effects of different experimental parameters on the composition, size, and structure of the prepared M-PtN / C alloy nanocrystals were studied. By characterizing the obtained M-PtCo / C alloy nanocrystals, the key factors affecting the composition, size, and structure of the alloy products were explored, thus achieving a controllable preparation method for disordered M-PtN / C alloy catalysts.
[0008] 2) Structural regulation of highly ordered Pt-based nanocrystalline structure M-PtN / C alloy catalysts.
[0009] The disordered M-PtN / C alloy catalyst obtained above was atomically ordered under appropriate heat treatment conditions, resulting in a highly durable and poison-resistant Pt-based catalyst. At high temperatures, the alloy nanocrystals undergo atomic rearrangement, tending to form an atomically ordered alloy with low thermodynamic entropy. The ordering transition temperature is influenced by many factors, including alloy nanoparticle size, heating / cooling rates, holding time, and heat treatment atmosphere (reducing, inert, or oxidizing). The authors focused on studying the effects of alloy composition, heat treatment atmosphere, temperature, and time on the degree of ordering in the M-PtN / C alloy catalyst, aiming to understand how to regulate the atomic ordering of Pt-based nanocrystalline M-PtN / C alloy catalysts.
[0010] The specific steps of the preparation method of the present invention are as follows:
[0011] Step 1: Selecting appropriate concentrations and amounts of Pt metal salt, transition metal salt precursor N, and metal salt precursor M according to a certain ratio, wherein the atomic ratio of Pt to transition metal N is in the range of 1:0.1-1:10; the atomic ratio of Pt to M is in the range of 1:0.001-1:1; the concentration of Pt metal salt is in the range of 0.1 mg / mL-10 mg / mL; the concentration of transition metal salt precursor N is in the range of 0.1 mg / mL-10 mg / mL; and the concentration of metal salt precursor M is in the range of 0.001 mg / mL-1.0 mg / mL; and mixing and stirring to obtain system A;
[0012] Step 2, adding the system A to an organic phase solvent and adjusting the pH value to obtain system B;
[0013] Step 3, using segmented temperature control to perform step-by-step reduction to obtain system C;
[0014] Step 4, adding the carbon support to the system C and stirring for adsorption to obtain system D;
[0015] Step 5: Filter the system D to remove water, wash with deionized water, and dry to obtain a disordered carbon-supported noble metal catalyst E.
[0016] Step 6: Treat the prepared carbon-supported noble metal catalyst at high temperature under an inert atmosphere to obtain an ordered carbon-supported noble metal catalyst F.
[0017] Furthermore, the step 1 further comprises: the Pt metal salt comprises chloroplatinic acid, platinum nitrate, and ethanolamine hydroxyplatinum; the transition metal salt precursor N comprises precursors of elements such as Co, Ni, and Cu, and a small amount of other metal salt precursors M comprises precursors of elements such as Mo, W, Ce, and Au;
[0018] Preferably, the step 2 further comprises: adjusting the pH value to be in the range of about 10 to 12. The organic phase solvent includes DMF, ethylene glycol, acetone and the like.
[0019] Preferably, the staged temperature control in step 3 is used for step-by-step reduction control: heating to 100 degrees Celsius, keeping warm and stirring for 60 minutes, then heating to 120 degrees Celsius, keeping warm and stirring for 180 minutes.
[0020] Preferably, step 5 is specifically as follows: filtering the system D to remove water, washing it with deionized water 5 to 6 times, and then drying and dehumidifying it in a vacuum drying oven, first drying it at 80°C for 2 hours, then keeping it warm at 60°C for 3 hours, and finally drying it at 40°C for 6 hours to obtain a carbon-supported precious metal catalyst.
[0021] Preferably, step 6 is specifically as follows: under N2 / H2 (gas flow ratio N2:H2=3:1) atmosphere conditions, the temperature is controlled in the range of 400-600°C, and heat treatment is performed for 2-3 hours to obtain an ordered carbon-supported noble metal catalyst.
[0022] Preferably, the precious metal is any one of platinum, palladium, rhodium, iridium and ruthenium.
[0023] Compared with the prior art, the beneficial effects of the present invention include:
[0024] 1) Selecting noble metals and transition metals, such as Pt and Co, to form an atomically ordered fine structure of the intermetallic nanocatalyst, resulting in a mismatch in the number of atoms in the lattice, creating compositional vacancies, increasing adsorption sites, optimizing the electronic structure, and regulating the bond length / bond energy of the ordered alloy;
[0025] 2) Doping with corrosion-resistant metal M elements (such as Mo, W, Ce, Au, etc.) is used to weaken the strength of the S-Pt bond, reduce the adsorption effect between SO2 and Pt atoms, and optimize the adsorption energy of Pt atoms to oxygen-containing species. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The present invention will be described below in conjunction with the accompanying drawings:
[0027] Figure 1 is the cyclic voltammogram of Pt / C catalyst in sulfur species solution;
[0028] Figure 2 The cyclic voltammogram of the Mo-PtCO / C catalyst in Example 1 is used to characterize the electrochemical active area.
[0029] Figure 3 : This is a half-cell linear scan diagram of the Mo-PtCO / C catalyst in Example 1, which characterizes the oxygen reduction mass specific activity;
[0030] Figure 4 TEM images of the catalysts of the examples; in the figure: a-200nm, b-20nm;
[0031] Figure 5 Figure 2 is a statistical distribution diagram of the particle size of the catalyst in the example. DETAILED DESCRIPTION
[0032] Example 1: Preparation of 1 gram of platinum-carbon catalyst
[0033] 1) Accurately weigh 1.8g of Pt in chloroplatinic acid solution, add 1.5g of cobalt nitrate solution, and then add 0.1g of molybdenum nitrate solution. Stir the three materials for 30 minutes to mix them evenly. This is recorded as A.
[0034] 2) Accurately measure 600 mL of DMF (dimethylformamide), then add material A, slowly add 0.5 mol / L sodium hydroxide to adjust the pH of the solution to 10-12, and stir for 2 hours. This is recorded as B.
[0035] 3) Then, B was placed in an oil bath and reacted with a reducing agent at 100°C for 1 hour, then kept at 120°C for 3 hours, and then cooled to room temperature and stirred for 2 hours to obtain system C.
[0036] 4) Accurately weigh 1 g of conductive carbon black and add it to the system C. Stir and adsorb for about 48 hours. Filter the catalyst to remove water and wash it 10 times with deionized water to obtain catalyst D.
[0037] 5) Dry and remove moisture in a vacuum drying oven by program, first drying at 80°C for 2 hours, then keeping at 60°C for 3 hours, and finally drying at 40°C for 6 hours to obtain a disordered carbon-supported noble metal catalyst E.
[0038] 6) Under N2 / H2 atmosphere (gas flow ratio N2:H2=3:1), the temperature was controlled in the range of 400-600°C and the catalyst was heat treated for 2-3 h to obtain an ordered carbon-supported noble metal catalyst F.
[0039] Example 2: A pilot test was conducted to prepare 10 g of a platinum-carbon catalyst having a platinum content of 60%.
[0040] 1) Accurately weigh 18g of Pt in chloroplatinic acid solution, add 15g of cobalt nitrate solution, and then add 1g of molybdenum nitrate solution. Stir the three materials for 30 minutes to mix them evenly. This is recorded as A.
[0041] 2) Accurately measure 6 L of DMF (dimethylformamide), then add material A, slowly add 0.5 mol / L sodium hydroxide to adjust the pH of the solution to 10-12, and stir for 2 hours. This is recorded as B.
[0042] 3) Then, B was placed in an oil bath and reacted with a reducing agent at 100°C for 1 hour, then kept at 120°C for 3 hours, and then cooled to room temperature and stirred for 2 hours to obtain system C.
[0043] 4) Accurately weigh 10 g of conductive carbon black and add it to the system C. Stir and adsorb for about 48 hours. Filter the catalyst to remove water and wash it with deionized water 10 times to obtain catalyst D.
[0044] 5) Dry and remove moisture in a vacuum drying oven by program, first drying at 80°C for 2 hours, then keeping at 60°C for 3 hours, and finally drying at 40°C for 6 hours to obtain a disordered carbon-supported noble metal catalyst E.
[0045] 6) Under N2 / H2 atmosphere (gas flow ratio N2:H2=3:1), the temperature was controlled in the range of 400-600°C and the catalyst was heat treated for 2-3 h to obtain an ordered carbon-supported noble metal catalyst F.
[0046] Example 3: A pilot test was conducted to prepare 20 grams of a platinum-carbon catalyst having a platinum content of 60%.
[0047] 1) Accurately weigh 36g of chloroplatinic acid solution containing Pt, add 30g of cobalt nitrate solution, and then add 2g of molybdenum nitrate solution. Stir the three materials for 30 minutes to mix them evenly. This is recorded as A.
[0048] 2) Accurately measure 12 L of DMF (dimethylformamide), then add material A, slowly add 0.5 mol / L sodium hydroxide to adjust the pH of the solution to 10-12, and stir for 2 hours. This is recorded as B.
[0049] 3) Then, B was placed in an oil bath and reacted with a reducing agent at 100°C for 1 hour, then kept at 120°C for 3 hours, and then cooled to room temperature and stirred for 2 hours to obtain system C.
[0050] 4) Accurately weigh 20 g of conductive carbon black and add it to the system C. Stir and adsorb for about 48 hours. Filter the catalyst to remove water and wash it 10 times with deionized water to obtain catalyst D.
[0051] 5) Dry and remove moisture in a vacuum drying oven by program, first drying at 80°C for 2 hours, then keeping at 60°C for 3 hours, and finally drying at 40°C for 6 hours to obtain a disordered carbon-supported noble metal catalyst E.
[0052] 6) Under N2 / H2 atmosphere (gas flow ratio N2:H2=3:1), the temperature was controlled in the range of 400-600°C and the catalyst was heat treated for 2-3 h to obtain an ordered carbon-supported noble metal catalyst F.
[0053] Example 4: A pilot test was conducted to prepare 100 g of a platinum-carbon catalyst having a platinum content of 60%.
[0054] 1) Accurately weigh 180g of chloroplatinic acid solution containing Pt, add 150g of cobalt nitrate solution, and then add 10g of manganese nitrate solution. Stir the three materials for 30 minutes until they are evenly mixed. This is recorded as A.
[0055] 2) Accurately measure 60 L of DMF (dimethylformamide), then add material A, slowly add 0.5 mol / L sodium hydroxide to adjust the pH of the solution to 10-12, and stir for 2 hours. This is recorded as B.
[0056] 3) Then, B was placed in an oil bath and reacted with a reducing agent at 100°C for 1 hour, then kept at 120°C for 3 hours, and then cooled to room temperature and stirred for 2 hours to obtain system C.
[0057] 4) Accurately weigh 100 g of conductive carbon black and add it to the system C. Stir and adsorb for about 48 hours. Filter the catalyst to remove water and wash it with deionized water 10 times to obtain catalyst D.
[0058] 5) Dry and remove moisture in a vacuum drying oven by program, first drying at 80°C for 2 hours, then keeping at 60°C for 3 hours, and finally drying at 40°C for 6 hours to obtain a disordered carbon-supported noble metal catalyst E.
[0059] 6) Under N2 / H2 atmosphere (gas flow ratio N2:H2=3:1), the temperature was controlled in the range of 400-600°C and the catalyst was heat treated for 2-3 h to obtain an ordered carbon-supported noble metal catalyst F.
[0060] The electrochemical active area oxygen reduction mass specific activity was tested according to the method in GB / T 20042.4-2009 Proton exchange membrane fuel cell part 4: electrocatalyst test method. The test results are shown in Table 1.
[0061] Table 1 Platinum content and electrochemical performance characterization results of Mo-PtCO / C catalyst
[0062] .
Claims
1. A method for preparing a carbon-supported noble metal catalyst resistant to poisoning by sulfur-containing species, characterized in that: The carbon-supported noble metal catalyst is represented by M-PtN / C, wherein: N represents a transition metal salt precursor, M represents a metal salt precursor, the transition metal salt precursor N is a Co precursor, and the metal salt precursor M is a Mo precursor; the preparation method thereof comprises the following steps: Step 1: Select appropriate concentrations of Pt metal salt, transition metal salt precursor N, and metal salt precursor M, and mix and stir the Pt metal salt, transition metal salt precursor N, and metal salt precursor M in a certain proportion to obtain system A; Step 2, adding system A to an organic phase solvent and adjusting the pH value to obtain system B; Step 3: using segmented temperature control to perform step-by-step reduction to obtain system C; the segmented temperature control to perform step-by-step reduction is as follows: heating to 100 degrees Celsius, stirring at this temperature for 60 minutes, then heating to 120 degrees Celsius, stirring at this temperature for 180 minutes; Step 4, adding the carbon support to system C and stirring for adsorption to obtain system D; Step 5: The system D was filtered to remove water and washed with deionized water; the system D was dried and dehumidified in a vacuum drying oven, first at 80°C for 2 hours, then at 60°C for 3 hours, and finally at 40°C for 6 hours to obtain a disordered carbon-supported noble metal catalyst E; Step 6: Treat the prepared disordered carbon-supported noble metal catalyst at high temperature under an inert atmosphere to obtain an ordered carbon-supported noble metal catalyst F.
2. The preparation method according to claim 1, characterized in that In step 1: The concentration range of Pt metal salt is 0.1mg / mL-10mg / mL; The concentration range of transition metal salt precursor N is 0.1 mg / mL-10 mg / mL; The concentration range of the metal salt precursor M is 0.001 mg / mL-1.0 mg / mL.
3. The preparation method according to claim 1, characterized in that In step 1: The atomic ratio of Pt to N ranges from 1:0.1 to 1:10; The atomic ratio of Pt to M ranges from 1:0.001 to 1:
1.
4. The preparation method according to claim 1, characterized in that In step 1: The Pt metal salt includes any one of chloroplatinic acid, platinum nitrate, and ethanolamine hydroxyplatinum.
5. The preparation method according to claim 1, characterized in that In step 2: Adjust the pH value to 10-12.
6. The preparation method according to claim 1, characterized in that In step 2: The organic phase solvent includes any one of DMF, ethylene glycol, acetone, and ethanol.
7. The preparation method according to any one of claims 1 to 5, characterized in that: The step 6 is specifically as follows: under N2 and H2 atmosphere conditions, the temperature is controlled in the range of 400-600°C, and heat treatment is performed for 1-3 hours to obtain an ordered carbon-supported precious metal catalyst, and the N2 and H2 gas flow ratio is N2:H2=3:1.
Citation Information
Patent Citations
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