Recent progress on the photocatalytic hydrogen evolution reaction over a metal sulfide cocatalyst-mediated carbon nitride system

Abstract

Under the dual background of energy and environment, the use of precious metal-free carbon nitride (g-C₃N₄) for photocatalytic H₂ evolution has attracted the attention of scientific researchers. Nonetheless, bulk g-C₃N₄ suffers from serious drawbacks, such as severe photo-generated carrier recombination and scarcity of active sites. Among numerous modification strategies, cocatalyst loading can extract photogenerated charges, provide effective active sites, and reduce reaction activation energy, thus obtaining better catalytic efficiency. Metal sulfides (MSs) are one of the materials that have replaced precious metals as cocatalysts in recent years owing to their unique electronic structure, low cost, and Gibbs free energy close to Pt. As a result, it is imperative to examine the research advancements in the MS/g-C₃N₄ system. In this paper, the structure and properties of g-C₃N₄ are reviewed, and the mechanism and role of a cocatalyst binding to g-C₃N₄ are discussed. Next, typical MS cocatalysts, including their modification strategies and loading techniques, are introduced. Finally, the article discusses the main issues and future research directions for MS/g-C₃N₄ systems. In conclusion, this review can enhance our comprehension of the correlation between g-C₃N₄ and cocatalysts, offering more efficient insights for the development of alternative MS cocatalysts.