Single-Atom Transition Metal Photocatalysts for Hydrogen Evolution Reactions

Abstract

Hydrogen is one of the potential fuels that is easily stored in ammonia compounds and reacts with oxygen in an environmentally friendly manner, producing water and transferring a significant amount of heat for powering mechanical facilities or transportation. Recently, single-atom photocatalysts have attracted significant attention owing to their ability to produce clean fuels or reduce gaseous pollution, thereby contributing to the preservation of our planet. Utilizing metals composed of a single atom on a semiconductor platform can improve the active sites, thereby increasing the efficiency of the hydrogen evolution reaction. This review focuses on the use of single-atom transition metals as photocatalysts in a solar-powered water-splitting system that produces hydrogen gas. The approach to synthesis, reaction mechanism, and current performance of these materials is exhaustively discussed. In addition, the main challenges and improvement strategies are highlighted.