Investigating the Influences of the Adsorbed Species on Catalytic Activity for Hydrogen Oxidation Reaction in Alkaline Electrolyte.

Catalysts for hydrogen oxidation reaction (HOR) in alkaline electrolyte are important for anion exchange membrane fuel cells. Understanding the role of OH- during the HOR catalytic process in alkaline electrolyte is essential to design highly active HOR catalysts. Here, we attempt to isolate the influence of OH- by using surface-controlled Pt based nanoparticles as the model catalysts. With a comparison of the HOR activity between PtNi nanoparticles and acid washed PtNi nanoparticles, which have almost the same hydrogen binding energies but much different OH binding energies, it was found that the HOR activity in alkaline electrolyte is not mainly controlled by the OH adsorption. Therefore, a bifunctional catalyst promoting OH adsorption may not useful for HOR in alkaline electrolyte. Tuning the hydrogen binding energy was found to be an efficient way to enhance the HOR activity, and making Pt base alloy is a reasonable way to tune the hydrogen binding energies.