The principle of the catalyst: Depending on the electrode, the fuel cell catalyst is also different. The anode catalyst is usually aimed at different fuels, with high stability and high activity, usually platinum carbon black or platinum black catalyst. Cathodic electrocatalysts mainly consider fuel penetration and oxygen reduction stability, so the choice of cathodic electrocatalysts should be more cautious. The raw materials are fused through solvents, metal precursors are added, the pH value is adjusted, and a reducing agent is added at a specific temperature to obtain an electrocatalyst with a metal platinum carbon black support.

      At present, the cathode and anode catalysts commonly used in proton exchange membrane fuel cells are platinum carbon black catalysts (Pt/C) or platinum black catalysts. Platinum carbon black is a supported catalyst dispersed from Pt nanoparticles onto carbon black supports. Unlike traditional chemical platinum carbon catalysts (platinum loading is less than 5%), platinum carbon black catalysts used in hydrogen fuel cells generally have a platinum loading capacity of more than 20%, which is very difficult to prepare. Platinum carbon black catalysts for hydrogen fuel cells require platinum nanoparticles with a particle size of 2 to 5 nm, a narrow particle size distribution, and a uniform dispersion on carbon. Since the surface energy of 2-5nm platinum nanoparticles is very large, it is easy to agglomerate, so the preparation of platinum carbon catalysts with a particle size of 2-5nm, a narrow particle size distribution, and uniform dispersion on carbon is very difficult, requiring special preparation process treatment.  

      There are many factors that affect the catalyst, including the size of the crystal and the degree of dispersion of the crystal, as well as the synthesis method of the catalyst, which also affects the efficacy of the catalyst. Although the platinum-carbon catalyst has high catalytic properties for oxygen reduction, the improper use of the catalyst will also cause the oxygen reduction process to be not a complete electronic reaction, thus reducing the catalytic activity. At the same time, it also has a great impact on the stability of the proton exchange membrane. Not only that, in the methanol fuel cell system, the platinum electrocatalyst is also easily poisoned by carbon monoxide, hydrogen sulfide, etc., and the anti-permeability is not high. Methanol penetration can greatly affect the cathode catalytic activity. Therefore, the research focuses on the selection of more active and more selective cathode catalysts. The selection direction should take into account the catalyst materials with high activation, low toxicity, anti-penetration and low cost. The advantages and disadvantages of electrocatalysts are mainly evaluated by catalyst activity and stability. By changing the performance of the support (specific surface area, pore structure, surface chemical properties, etc.), the content and particle size of the active metal in the catalyst, the macroscopic and microscopic distribution of the active metal on the support, etc. The ability to prepare well-dispersed high surface area electrocatalysts containing platinum has greatly improved the feasibility of many electrochemical processes. This new process provides an excellent high-purity catalyst suitable for forming highly uniform electrode structures.

physicochemical parameters