Recent developments in metal phosphide and sulfide electrocatalysts for oxygen evolution reaction

Oxygen evolution reaction (OER), as an important half-reaction involved in water splitting, has been intensely studied since the last century. Transition metal phosphide and sulfide-based compounds have attracted increasing attention as active OER catalysts due to their excellent physical and chemical characters, and massive efforts have been devoted to improving the phosphide and sulfide-based materials with better activity and stability in recent years. In this review, the recent progress on phosphide and sulfide-based OER electrocatalysts in terms of chemical properties, synthetic methodologies, catalytic performances evaluation and improvement strategy is reviewed. The most accepted reaction pathways as well as the thermodynamics and electrochemistry of the OER are firstly introduced in brief, followed by a summary of the recent research and optimization strategy of phosphide and sulfide-based OER electrocatalysts. Finally, some mechanistic studies of the active phase of phosphide and sulfide-based compounds are discussed to give insight into the nature of active catalytic sites. It is expected to indicate guidance for further improving the performances of phosphide and sulfide-based OER electrocatalysts.