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Catalyst

‌The main function of hydrogen fuel cell catalysts is to promote the occurrence of hydrogen oxidation reaction and oxygen reduction reaction, thereby generating electricity. In the electrochemical reaction of fuel cells, there are mainly two reactions involved, namely hydrogen oxidation (HOR) at the anode and oxygen reduction (ORR) at the cathode. The electrochemical reaction process at the anode is very fast, and the reaction process at the cathode is slow. In order to improve the overall reaction efficiency of the fuel cell, a catalyst is needed to increase the reaction rate of the cathode.

Product Recommendations

Catalyst Type

Pure platinum catalyst

Platinum (Pt) has good molecular adsorption and dissociation characteristics, so platinum catalyst has become the most ideal and currently the only commercial catalyst material. Platinum has high catalytic activity for both hydrogen oxidation reaction and oxygen reduction reaction.

Low platinum catalyst

Since platinum metal is expensive, scientists and companies improve the stability and activity of the catalyst by alloying with other metals, while also reducing the use of platinum. These alloys mainly use cobalt, nickel, iron, copper, zinc, etc.

Non-platinum-based catalysts

These catalysts mainly include palladium-based catalysts, non-precious metal catalysts and non-metal catalysts. Non-precious metal catalysts include iron, cobalt, nickel, etc. The most common non-metal catalysts are carbon-based catalysts, such as carbon nanotubes, carbon fibers, graphene, etc.

Preparation of catalysts

Overview of impregnation reduction method

Impregnation reduction method is one of the earliest methods used to prepare supported catalysts. It obtains the catalyst by impregnating the salt solution of the precious metal precursor onto the carrier and then performing a reduction treatment.
Steps: Disperse the carbon carrier evenly in the solvent, add the precious metal precursor for impregnation, and then add an excess reducing agent at a certain temperature or pyrolyze and reduce in a reducing atmosphere to obtain a Pt/C catalyst.
Features: This method is simple and easy, but the catalyst particle size is related to the carrier, and the reaction conditions need to be precisely controlled to obtain the ideal catalyst performance.

Other methods

Polyol reduction method, organic solvent thermal method, microemulsion method. These methods are also commonly used to prepare hydrogen fuel cell electrode catalysts, but due to their high production costs, complex process control and the use of organic reagents, researchers have been seeking improvements and optimizations.

Overview of colloid method

The colloid method is to prepare the catalyst precursor into a colloid using a reducing agent in a specific solvent, and evenly and stably disperse it in the solvent, and then combine it with the carrier to prepare the catalyst.
Features: The colloid method can prepare metal catalysts with narrow particle size distribution and small particle size. To prevent catalyst aggregation, protective agents such as charged surfactants or polymers are often used.