A Mini Review: Recent Advances in Asymmetrically Coordinated Atom Sites for High-Efficiency Hydrogen Evolution Reaction

Energy is the substance foundation of human society. Single-atom catalysts (SACs) have emerged as promising electrode materials in the energy field owing to their unique characteristics. It was demonstrated that the hydrogen evolution reaction (HER) performance of SACs relies on the metal-centric species and the corresponding local coordination engineering. Herein, the recent progress relating to asymmetric atomic catalysts for the HER is reviewed, including low coordination, heteroatomic coordination, and bimetallic coordination. In addition, the connection between the coordination structures and the presented electrocatalytic performance was discussed. The main challenges that need to be addressed for the asymmetric atomic catalysts in the HER are summarized. Finally, some insights into the development of high-quality asymmetric atomic catalysts are included.