Underlying aspects of surface amendment strategies adopted in electrocatalysts for overall water splitting under alkaline conditions

Hydrogen (H2) is a well-known and efficient energy carrier that can be utilized as future green fuel. H2 production via electrolysis of water can be considered as the most suitable energy conversion technology. For water electrolysis, the competent catalysts are noble metal-associated electrocatalysts such as Pt, RuO2, IrO2, etc. Due to their high cost and scarcity-to-performance ratio, intense research is being carried out for the fabrication of inexpensive, stable, and extremely active transition metal-based electrocatalyst for water electrolysis. In this context, surface modification strategies such as nanostructure engineering, introducing doping elements, defects or vacancies, and composition modulation for enhancing electrocatalysts properties are highly pursued in the recent literature. These strategies contribute to the modification of electronic structure, boosting electronic conductivity, and enhancing the exposure of catalytically active sites. This review reports the recent progress on various synergistic surface modulation aspects for advancing the catalyst's performance for overall water electrolysis in alkaline media.