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.

Single-Atom Ru Catalyst-Decorated CNF(ZnO) Nanocages for Efficient H2 Evolution and CH3OH Production

“…The remarkable performance of SACs pertaining to the hydrogen evolution reaction (HER) and the CO 2 reduction reaction (CO 2 RR) has recently been reviewed. 14,15 A heteroatom, such as nitrogen in a N−C framework, is a great support for anchoring metal atoms separately due to its special electronic and structural characteristics, which promote bonding between the singly dispersed atoms and carbon support through metal−C and metal−N−C coordination. 16 The N atoms in ZIF-8 serve as versatile supporting precursors and have emerged as potentially effective light-harvesting supports for loading single metal atoms with high contents, and they may also act as anchoring sites.…”

“…This atomic-level precision allows for the precise adjustment of light absorption, charge separation, and surface reactivity, ultimately resulting in exceptional photonic conversion efficiency. − In this regard, the synthesis of SACs has emerged as a promising strategy for improving the performance of the redox reactions. − SACs recognized as new approaches in heterogeneous catalysis with a high level of structural and chemical performance, accomplishing the minimum use of precious manipulation metals with a unique control over atomistic effects, exhibit exceptional catalytic activity, selectivity, and stability, owing to their unique electronic and geometric properties. The remarkable performance of SACs pertaining to the hydrogen evolution reaction (HER) and the CO 2 reduction reaction (CO 2 RR) has recently been reviewed. , …”