Significance of oxophilic site in alkaline hydrogen evolution and oxidation reaction: Is it playing the same role?

Abstract

Regenerative alkaline anion-exchange membrane fuel cells (AAEMFC) represent a potential technology for facilitating the integration of renewable energy generation. The hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) are the principal reactions in regenerative fuel cells. Numerous studies have been conducted in this area, however for electrochemical processes, it is crucial to comprehend the mechanism underlying the reaction by carefully optimizing the adsorption of the intermediates. Recent research suggests that the oxophilic site is important for the alkaline HER and HOR, and that having the oxophilic site on the catalyst's surface can speed up the reaction. When it comes to Alkaline HER, the oxophilic site expedited the adsorption and scissoring of the H–OH molecule to provide a steady supply of proton, while *OH adsorption is vital for HOR. An in-depth description of this concept, together with innovations in the fabrication of the oxophilic site, is something that requires urgent attention. This review begins by elucidating the significance of the oxophilic sites in both reactions, followed by a discussion on the advanced fabrication techniques employed for the synthesis of the oxophilic site. We have also engaged in discussions regarding future directions and challenges in the research within this area.