Metal atom-induced microenvironment regulation in polymeric carbon nitride for photocatalytic hydrogen evolution

Developing high-efficiency and stable semiconductor photocatalysts is crucial for realizing the practical applications of photocatalysis. Polymeric carbon nitride (CN) has been verified as a promising candidate for photocatalytic H₂ evolution due to a series of outstanding physicochemical properties. Over the past decade, significant progress has been made in enhancing the photocatalytic H₂ evolution of CN-based photocatalysts through various strategies based on thermodynamics or kinetics. Recently, metal atom decoration has provided a new avenue for modifying CN by precisely regulating its microenvironment. This paper provides a comprehensive review of recent advancements in metal atom-decorated CN photocatalysts for photocatalytic H₂ evolution via water splitting, encompassing single metal atom decorated CN, dual metal atoms decorated CN, and single metal atom and cluster co-decorated CN, in which the vital roles of metal atoms are highlighted. Furthermore, the challenges and opportunities in the development of advanced CN-supported metal atom photocatalysts are thoroughly summarized.