Low-platinum high active core-shell structure catalyst and preparation method thereof

A technology of catalyst and shell structure, applied in the field of low-platinum high-activity core-shell structure catalyst and its preparation, can solve the problems of expensive platinum and achieve the effects of solving cost and performance, easy control of reaction conditions, and simple preparation process

Inactive Publication Date: 2010-03-10

NORTHWEST NORMAL UNIVERSITY

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AI-Extracted Technical Summary

Problems solved by technology

At present, most of the catalysts used in low-temperature fuel cells are based on the precious metal platinum, and the price of platinum is ...

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Abstract

The invention provides a high active core-shell structure catalyst used for low temperature fuel cell. The preparation method comprises the following steps: adopting carbon powder or carbon nanotubesas carrier, coating single-layer or two-layer platinum which is reduced by reductant, on the metal-based core to form a core-shell structure and loading the structure on carbon powder or carbon nanotubes carrier. The catalyst has low platinum loading and high catalytic activity so that platinum loading is low, the activity of the catalyst is high; the contradiction between the cost and performanceof catalyst is effectively solved, and the high active core-shell structure catalyst plays an extremely important role in solving the current problems of the fuel cell.

Application Domain

Cell electrodesCatalyst activation/preparation +1

Technology Topic

ChemistryCarbon nanotube +8

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Examples

Experimental program(5)

Example Embodiment

[0024] Example 1: Preparation of Pd@Pt/C catalyst

[0025] Add 42.9mg of palladium chloride to a 50ml round-bottomed flask, add 25ml of ethylene glycol, add magnets and stir, ultrasonically for more than 0.5 hours to completely dissolve. Add 193.8mg of sodium citrate, stir to completely dissolve, adjust the pH of the solution with 5% KOH/EG solution to 9; add 102.8mg of sodium formate, 100mg of carbon powder, stir for 0.5 hours, ultrasonic for 0.5 hours; transfer the resulting solution to high pressure The reaction kettle is placed in an oven and reacted at 160°C for 8 hours; the resultant is suction filtered, washed with water three times until no chloride ions are detected in the solution, and dried in vacuum at 70°C to constant weight to obtain a catalyst precursor.

[0026] Weigh 17.0 mg of chloroplatinic acid, add it to a round-bottomed flask, and add 20 ml of ethylene glycol (ethylene glycol is a solvent and also a reducing agent), use 5% KOH/EG solution to adjust the pH value of the solution = 9; add the aforementioned preparation 50mg of the catalyst precursor, under stirring at 60°C for 6 hours, cooling, and standing for more than 4 hours. After suction filtration, it was repeatedly washed with triple water and dried to obtain Pd@Pt/C catalyst.

[0027] It is determined that in the Pd@Pt/C catalyst, Pt accounts for 5% of the total mass of the catalyst; Pd accounts for 20% of the total mass of the catalyst. The particle size of the active component is 4.4nm. Compared with commercial Pt/C, the oxygen reduction half-potential of Pd@Pt/C catalyst is positively shifted by about 8mV.

Example Embodiment

[0028] Example 2: Preparation of PdFe@Pt/C catalyst

[0029] Add 19.2mg of palladium chloride and 106.0mg of ferric chloride into a 50ml round-bottomed flask with 25ml of ethylene glycol, stir with a magnet, and ultrasound for more than 0.5 hours to completely dissolve them; add 294.3mg of sodium citrate and stir until complete Dissolve. Adjust the pH of the solution to 10 with a 5% KOH/EG solution, add 156.2 mg of sodium formate and 100 mg of carbon nanotubes, stir for 0.5 hours, and ultrasonic for 0.5 hours.

[0030] The above solution was transferred to an autoclave, placed in an oven, and reacted at 160°C for 8 hours. The resultant was suction filtered, washed with water three times until no chloride ions were detected in the solution, and dried in vacuum at 70°C to constant weight to obtain a catalyst precursor.

[0031] Weigh 9.4 mg of chloroplatinic acid, add it to a round bottom flask, and add 20 ml of ethylene glycol, 5% KOH/EG solution to adjust the pH of the solution to alkaline 9, add 1 ml of formic acid, and add 50 mg of the catalyst precursor prepared above, The reaction was carried out at 60°C for 4 hours with stirring, cooled, and allowed to stand for more than 4 hours. After suction filtration, it is washed repeatedly with triple water and dried to obtain PdFe@Pt/C catalyst.

[0032] It is determined that in the PdFe@Pt/C catalyst, Pt accounts for 4.4% of the total catalyst mass; Pd accounts for 12% of the total catalyst mass, and Fe accounts for 11% of the total catalyst mass. The particle size of the active component is 4.6nm. Compared with commercial Pt/C, the oxygen reduction half-potential of Pd@Pt/C catalyst is positively shifted by about 17mV.

Example Embodiment

[0033] Example 3: Preparation of PdCo@Pt/C catalyst

[0034] Add 36.3mg of palladium chloride and 32.3mg of cobalt chloride to a 50ml round-bottomed flask, then add 25ml of ethylene glycol, stir with a magnet, and ultrasound for more than 0.5 hours to completely dissolve it; add 232.0mg of sodium citrate and stir to completely dissolved. Adjust the pH of the solution to 9 with 5% KOH/EG solution, add 123.12 mg of sodium formate, 100 mg of carbon powder, stir for 0.5 hours, and ultrasonic for 0.5 hours; transfer the solution to the autoclave and place it in an oven at 160°C React for 8 hours. The resultant was suction filtered, washed with water three times until no chloride ions were detected in the solution, and dried in vacuum at 70 degrees to constant weight to obtain a catalyst precursor.

[0035] Weigh 8.9 mg of chloroplatinic acid, add it to a round bottom flask, and add 20 ml of ethylene glycol, adjust the pH of the solution to alkaline 10 with 5% KOH/EG solution, add 1 ml of formaldehyde, and add 50 mg of the catalyst precursor prepared above , Under stirring, react at 80°C for 2 hours, cool and let stand for more than 4 hours. After suction filtration, repeated washing with triple water and drying were performed to obtain PdCo@Pt/C catalyst.

[0036] It has been determined that in the PdCo@Pt/C catalyst, Pt accounts for 3.6% of the total catalyst mass; Pd accounts for 12% of the total catalyst mass, and Co accounts for 14% of the total catalyst mass. The particle size of the active component is 4.7nm. Compared with commercial Pt/C, the oxygen reduction half-potential of Pd@Pt/C catalyst is positively shifted by about 11mV.

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PUM

Property	Measurement	Unit
Particle size	4.6	nm
Particle size	4.7	nm
Particle size	5.2	nm
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Simple preparation process

Nano porous high-temperature-insulating material taking thixotropic colloid as template agent and preparation method for high-temperature-insulating material

InactiveCN105314999AAvoid reunion and scatter problemsSimple preparation processCeramicwareThermal conductivityAerospace

Owner:浙江圣润纳米科技有限公司

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Low-platinum high active core-shell structure catalyst and preparation method thereof

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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