Recent advances in the application of phosphates and borates as electrocatalysts for water oxidation

Electrocatalytic oxygen evolution reaction (OER) is considered as a core reaction for clean energy generation and storage. OER, as a half-reaction of water splitting, is a complicated and sluggish process. In recent years, increasing efforts have been devoted to improving the OER efficiency of transition metal phosphates and borates because of their outstanding activity and stability. In this review, the recent advances in transition metal phosphate- and borate-based electrocatalysts are summarized, including the synthetic approaches, catalytic performances, and the improvement strategies. First, the reaction pathways and thermodynamic of OER are introduced. The nature of catalytic active species of phosphates and borates are also discussed. Finally, a perspective for designing transition metal phosphates and borates to OER with high performance has been provided.