A review of g-C3N4-based photocatalytic materials for photocatalytic CO2 reduction

Currently, the concentration of carbon dioxide (CO2) has exceeded 400 ppm in the atmosphere. Thus, there is an urgent need to explore CO2 reduction and utilization technologies. Photocatalytic technology can convert CO2 to valuable hydrocarbons (CH4, CH3OH, and C2H5OH, etc.), realizing the conversion of solar energy to chemical energy as well as solving the problems of fossil fuel shortage and global warming. Graphitic carbon nitride (g-C3N4), as a two-dimensional nonmetallic semiconductor material, shows great potential in the field of CO2 photoreduction due to its moderate bandgap, easy synthesis method, low cost, and visible light response properties. This review elaborates the research progress of g-C3N4-based photocatalysts for photocatalytic CO2 reduction. The modification strategies (e.g., morphology engineering, elemental doping, crystallinity modulation, cocatalyst modification, and constructing heterojunction) of g-C3N4-based photocatalysts for CO2 reduction application have been discussed in detail. Finally, the challenges and development prospects of g-C3N4-based photocatalytic materials for CO2 reduction are presented.