Single-Atom Catalysts for the Hydrogen Evolution Reaction

Electrocatalytic hydrogen evolution reaction (HER) is recognized as a promising way to generate clean hydrogen energy. However, its large-scale application requires the development of cheap and efficient catalysts. An increasing number of reports have been published lately on the HER over single atom catalysts (SACs) owing to the high catalytic activity, stability and maximum atom utilization of SACs, of which the final point endows noble-metal catalysts with low costs. In this Review, we highlight the electrochemical applications of all reported SACs in the HER, with a particular focus on the discussion of their catalytic properties and mechanisms at the atomic level. The main advantages and challenges of SACs are also summarized. This Review aims to provide a comprehensive understanding of current and future applications of SACs in the HER.