CN-121460609-B - Preparation method and application of tungsten carbide doped carbon-supported platinum Pt/C catalyst

Abstract

The invention discloses a preparation method and application of a tungsten carbide doped carbon-supported platinum Pt/C catalyst, wherein tungsten oxide and a carbon carrier are mixed in an organic solvent by a hydrothermal method to obtain precursor powder; the precursor powder is subjected to high-temperature heat treatment, cooled to obtain W-C powder, then mechanically mixed with conductive carbon powder in an organic solvent to obtain a W-C/C composite carrier, dispersed in the solvent, added with a platinum source for reduction reaction, washed and dried to obtain a Pt/W-C/C catalyst, and the catalyst is prepared into slurry which is coated on two sides of a proton exchange membrane to prepare the three-in-one membrane electrode. Through the mode, the preparation method provided by the invention is relatively simple in process and strong in controllability, ensures uniform formation and high stability of the W-C framework through a technology combining hydrothermal synthesis and high-temperature carbonization, and realizes controllable preparation of the high-performance and high-durability membrane electrode through an optimized platinum carrying process and an ion liquid doping process.

Inventors

• QIAN YU
• SHANG ZIQI
• LIU JING
• XU BIN
• LAI ZHIYONG
• WU CHENGXIANG

Assignees

• 江苏源氢新能源科技股份有限公司

Dates

Publication Date

20260505

Application Date

20260107

Claims (9)

1. 1. The preparation method of the tungsten carbide doped carbon-supported platinum Pt/C catalyst is characterized by comprising the following steps of: (1) Mixing tungsten oxide and a carbon carrier in an organic solvent by a hydrothermal method, filtering and drying after reaction to obtain precursor powder; (2) Carrying out heat treatment on the precursor powder obtained in the step (1) at 1500-2000 ℃ under the protection of inert atmosphere, enabling tungsten oxide and carbon to react to form a tungsten carbide W-C framework, and cooling to obtain W-C powder; (3) Mechanically mixing the W-C powder obtained in the step (2) with conductive carbon powder according to the mass ratio of (1-4) (9-6) in an organic solvent for 2-4 h, filtering and drying to obtain a W-C/C composite carrier; (4) Dispersing the W-C/C composite carrier obtained in the step (3) in a solvent, adding a platinum source, then adding a reducing agent under the condition of pH value of 8-12 for reduction reaction, washing and drying after the reaction to obtain the Pt/W-C/C catalyst.
2. 2. The method for preparing a tungsten carbide doped carbon supported platinum Pt/C catalyst according to claim 1, wherein in step (1), the tungsten oxide is one of tungsten trioxide (WO 3 ) or tungsten dioxide (WO 2 ).
3. 3. The method for preparing a tungsten carbide doped carbon supported platinum Pt/C catalyst according to claim 1, wherein in step (1), the carbon carrier is one of XC-72 or acetylene black ECP 300.
4. 4. The method for preparing a tungsten carbide doped carbon supported platinum Pt/C catalyst according to claim 1, wherein in the step (1), the hydrothermal reaction is performed at a temperature of 100-200 ℃ for a time of 2-3 h.
5. 5. The method for preparing a tungsten carbide doped carbon supported platinum Pt/C catalyst according to claim 1, wherein in step (1) and step (3), the organic solvent is one or a mixture of several of N-methylpyrrolidone, tetrahydrofuran or N-butanol.
6. 6. The method for preparing a tungsten carbide doped carbon-supported platinum Pt/C catalyst according to claim 1, wherein in the step (4), the platinum source is chloroplatinic acid, and the reducing agent is sodium borohydride or sodium citrate.
7. 7. A membrane electrode comprising the Pt/W-C/C catalyst prepared by the method of any one of claims 1 to 6, wherein the method comprises mixing the Pt/W-C/C catalyst, an ionic liquid, and an isopropyl alcohol solution to prepare a catalyst slurry, coating the slurry on both sides of a proton exchange membrane to form a cathode catalytic layer and an anode catalytic layer, and assembling the cathode catalytic layer and the proton exchange membrane into a three-in-one membrane electrode.
8. 8. The membrane electrode according to claim 7, wherein the ionic liquid is an imidazole ionic liquid, and comprises one or more of 1-ethyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, 1-butyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt or 1-butyl-2, 3-dimethylimidazole bis-trifluoromethanesulfonyl imide salt.
9. 9. The membrane electrode of claim 7, wherein the platinum loading in the cathode catalytic layer is 0.2-0.4 mg/cm2 and the platinum loading in the anode catalytic layer is 0.05-0.15 mg/cm2.

Description

Preparation method and application of tungsten carbide doped carbon-supported platinum Pt/C catalyst Technical Field The invention relates to the field of catalysts for fuel cells, in particular to a preparation method of a tungsten carbide doped carbon-supported platinum Pt/C catalyst and a membrane electrode CCM comprising the catalyst. Background Currently, conventional Pt/C catalysts face multiple challenges in operation. Firstly, hydrogen peroxide (H 2O2) and oxygen-containing groups such as hydroxyl radicals (OH) derived from the hydrogen peroxide can be generated in the running process of the battery, and the strong oxidizing substances can attack the carbon carrier and the proton membrane, so that the catalyst loss and the chemical attenuation of the membrane component are caused. Second, pt nanoparticles are prone to dissolution, migration and ostwald ripening under potential cycling, resulting in a decrease in active area. In addition, the proton conductivity of the catalyst layer is drastically deteriorated and the poisoning sensitivity of the catalyst to impurities such as carbon monoxide (CO) is increased at the time of low humidity operation, which severely restricts the life and reliability of the battery. In order to cope with the above problems, there have been studies on attempts to introduce auxiliary components to improve catalyst stability. Among them, tungsten carbide (W-C) is attracting attention due to its high melting point, excellent chemical stability and unique noble metal-like catalytic properties. W-C has stable structure in an acidic environment, can effectively capture H 2O2 and OH free radicals, lighten the damage of the H 2O2 and OH free radicals to a catalyst and a membrane, and also has certain CO poisoning resistance. However, single material modifications tend to be limited in effectiveness. Therefore, there is a need for a novel catalytic layer structure that can cooperate with Pt catalysts to provide multiple protections, physically form a protective layer, inhibit the ripening and migration of Pt particles, and simultaneously maintain proton conduction at low humidity, thereby synergistically improving the overall durability of the membrane electrode under severe conditions from multiple dimensions, such as inhibiting catalyst decay, maintaining proton conduction, and resisting chemical attack. Disclosure of Invention The invention mainly solves the technical problems of providing a preparation method of a tungsten carbide doped carbon-supported platinum Pt/C catalyst, and a membrane electrode comprising the catalyst, and the problems of the existing Pt/C catalyst in terms of durability, low-humidity operation and anti-attenuation performance can be comprehensively solved by constructing a membrane electrode which is formed by loading platinum by a tungsten carbide doped composite carrier and forming a synergistic protection system with ionic liquid in a catalytic layer. In order to solve the technical problems, the invention adopts a technical scheme that the preparation method of the tungsten carbide doped carbon-supported platinum Pt/C catalyst comprises the following steps: (1) Dispersing tungsten oxide and a carbon carrier in an organic solvent according to the mass ratio of (3-4) (7-6), mixing by a hydrothermal method, laying a foundation for forming a uniform W-C framework subsequently, filtering after reaction, and drying to obtain precursor powder; (2) Carrying out heat treatment on the precursor powder obtained in the step (1) at 1500-2000 ℃ under the protection of inert atmosphere, enabling tungsten oxide and carbon to react to form a tungsten carbide W-C framework, and cooling to obtain W-C powder; (3) Mechanically mixing the W-C powder obtained in the step (2) with conductive carbon powder in an organic solvent, filtering and drying to obtain a W-C/C composite carrier with the chemical protection function of W-C and excellent conductivity of a carbon material; (4) Dispersing the W-C/C composite carrier obtained in the step (3) in a solvent, adding a platinum source, then adding a reducing agent under the condition of pH value of 8-12 for reduction reaction to form platinum nano particles with uniform particle size, washing and drying after the reaction to obtain the Pt/W-C/C catalyst. The catalyst combines the free radical scavenging capacity of W-C and the catalytic activity of high-dispersion Pt, and improves the overall durability of the catalyst. In a preferred embodiment of the present invention, in step (1), the tungsten oxide is one of tungsten trioxide (WO 3) or tungsten dioxide (WO 2) to provide an effective tungsten source. In a preferred embodiment of the present invention, in step (1), the carbon support is one of XC-72 or acetylene black ECP300 to provide an initial support having a high specific surface area. In a preferred embodiment of the present invention, in step (1), the hydrothermal reaction is carried out at a temperature of 100-200