Semiconductor photocatalysis via sunlight-driven photoredox reactions to directly convert solar energy into chemical energy or to mineralize organic pollutants, is regarded as a long-term solution to address the global energy and environmental problems. Recently, graphitic carbon nitride (g-C₃N₄), a polymeric semiconductor has been widely used as a low-cost, stable and metal-free visible-light-active photocatalyst in the sustainable utilization of solar energy, such as water splitting, organic photosynthesis and environmental remediation. This has attracted worldwide attention from energy and environmental relative fields. In this review, some recent advances in g-C₃N₄ photocatalysis are present, including the theoretical research of chemical structure and features of g-C₃N₄, metal/non-mental doping of g-C₃N₄ to adjust the semiconductive electronic band structure, soft/hard templates assisted the synthesis of g-C₃N₄ nanoarchictures, surface modification of g-C₃N₄ to overcome the high kinetic barrier for water reduction/oxidation, and as well as the construction of g-C₃N₄ based heterojunctions and composite photocatalysts to promote the separation of energy-wasteful charge recombination. The prospects for the development of highly efficient g-C₃N₄ based photocatalysts are also discussed.

Contents
1 Introduction
2 Mechanism study of g-C₃N₄ photocatalyst
2.1 Semiconductive band structure of g-C₃N₄
2.2 Photocatalytic performance of g-C₃N₄
3 Development of g-C₃N₄ photocatalyst
3.1 Theoretical calculation of g-C₃N₄ photocatalyst
3.2 Synthesis optimization of g-C₃N₄ photocatalyst
3.3 Nanostructuring g-C₃N₄ photocatalyst
3.4 Synthesis of g-C₃N₄ photocatalyst by copolymeri-zation
3.5 Semiconductor doping of g-C₃N₄ photocatalyst
3.6 Surface modification of g-C₃N₄ photocatalyst
3.7 Sensitization of g-C₃N₄ photocatalyst
3.8 g-C₃N₄ based composite photocatalysts
4 Conclusion and outlook