Current and future trends for spinel-type electrocatalysts in electrocatalytic oxygen evolution reaction

Fabricating advanced oxygen evolution reaction (OER) catalysts is of vital significance for the effectiveness of water splitting. Endowed with high catalytic performance toward OER, spinel-type materials are universally agreed to be one of most promising alternatives to the currently used noble metal-based electrocatalysts. Nonetheless, a major issue that limits the practical applications of spinel-type materials as OER catalysts is the high OER overpotential. Aiming to enable spinel-type materials to serve as practical OER electrocatalysts, intensive endeavors have been dedicated to the optimization of electrochemical properties by modifying their structures and compositions. Given that, summarizing the recent progress of spinel electrocatalysts with modified electronic configurations and their applications in OER is highly desirable. This review starts by introducing the OER mechanisms which involves with the conventional adsorbate evolution mechanism (AEM) and lattice oxygen mechanism (LOM). In addition, the OER pathways with spinel electrocatalysts and some important descriptors have also been summarized. Afterwards, many advanced strategies that have been demonstrated to be effective for optimizing the electrochemical properties of spinel electrocatalysts are predominately discussed. Finally, the perspective insights in advancing deep understanding and fabricating excellent spinel-type electrocatalysts are also manifested.