Utilizing photocatalysis technology to convert solar energy into chemical energy or direct degradation and mineralization of organic pollutants is a long-term solution to solve the problem of energy shortage and environmental pollution. Polymer type graphite carbon nitride (g-C₃N₄) possesses a similar structure with graphene and has been attracted widespread attention as a novel photocatalyst for the light catalytic conversion of solar energy due to its excellent chemical stability and unique electronic band structure. Moreover, the g-C₃N₄ can be used as a low-cost, stable and metal-free visible-light-driven photocatalyst in the degradation of pollutants, water splitting for hydrogen and oxygen evolution and organic synthesis, as the precursors of g-C₃N₄ are inexpensive and the synthesis is comparatively simple. Many efforts are still needed to overcome the limitation of fast recombination for pure g-C₃N₄ in practical application. In this review, recent research progress for g-C₃N₄ has been reviewed, including metal/non-mental doping, semiconductor coupling, depositing with metals. In addition, the catalytic mechanism for the g-C₃N₄-based composite is also reviewed.

Contents
1 Introduction
2 g-C₃N₄-metal composites photocatalyst
3 g-C₃N₄-oxide composites photocatalyst
4 g-C₃N₄-sulfide composites photocatalyst
5 g-C₃N₄-bismuth compounds composites photocatalyst
6 g-C₃N₄-carbon composites photocatalyst
7 Other g-C₃N₄ composites photocatalyst
8 Conclusion