The progress of g-C₃N₄ in photocatalytic H₂ evolution: From fabrication to modification

Polymeric semiconductor, Graphitic Carbon Nitride (g-C₃N₄), has emerged as one of the desired materials in photocatalytic hydrogen evolution (PHE) due to its visible-light activity, facile accessibility, low-cost, chemical stability, as well as the unique layered structure. However, pure g-C₃N₄ photocatalyst suffers from limited photocatalytic performance due to the low efficiency of charge carrier separation and serious charge recombination. Researches over the past few decades have shown that the photocatalytic active of g-C₃N₄ can be easily affected by many factors including spatial morphology, electronic structure, as well as the interaction between g-C₃N₄ and other materials. This review gives a comprehensive introduction over the basic properties and the development of g-C₃N₄ in PHE. A brief history and the basic properties are firstly introduced. After then, this review introduces the fabrication and the limits of g-C₃N₄ in PHE, followed by the rational methods in improving the photocatalytic active of g-C₃N₄ including the self-modification strategies (e.g., molecular structure regulation, defect engineering and microstructure manipulation) and the exogenous modification strategies (e.g., the deposition of co-catalyst and the construction of g-C₃N₄ based heterostructure). Lastly, this review discusses the major challenges and opportunities of g-C₃N₄ in photocatalytic field. It is believed that this review is benefit for proposing more effective solutions in developing high active g-C₃N₄ photocatalysts based on a comprehensive understanding of g-C₃N₄ material.