Recent advances in single-atom electrocatalysts supported on two-dimensional materials for the oxygen evolution reaction

As a half-reaction of electrolytic water-splitting for hydrogen generation, the oxygen evolution reaction (OER) is the major bottleneck due to the sluggish kinetics of the four-electron transfer reaction. Developing high-efficiency and cost-effective OER electrocatalysts is crucial to the advancement of water-splitting. Besides the conventional metal-based nanoparticle catalysts, constructing single-atom catalysts (SACs) on two-dimensional (2D) materials has become an important research direction in recent years. In this review, we summarize the recent strategies for the synthesis of SACs, the experimental and theoretical studies of 2D material-based SACs to enhance the OER performance, and the rational design principles of SACs toward the OER, as well as the challenges and future directions. A discussion is provided for a better understanding of the OER, to guide the optimization of electrocatalysts, and for possible future candidates of SACs. This review summarizes the recent theoretical and experimental progress in two-dimensional material-based single-atom catalysts for the electrochemical OER. The remaining challenges and an outlook on future directions are highlighted.