Reducing CO2 into high value fuels and chemicals is considered a great challenge in the 21st century. Efficiently activating CO2 will lead to an important way to utilize it as a resource. This article reviews the latest progress of g-C3N4 based catalysts for CO2 reduction. The different synthetic methods of g-C3N4 are briefly discussed. Article mainly introduces methods of g-C3N4 shape control, element doping, and use of oxide compounds to modify g-C3N4. Modified g-C3N4 has more reactive sites, which can significantly reduce the probability of photogenerated electron hole recombination and improve the performance of photocatalytic CO2 reduction. Considering the literature, the hydrothermal method is widely used because of its simple equipment and process and easy control of reaction conditions. It is foreseeable that hydrothermal technology will continue to innovate and usher in a new period of development. Finally, the prospect of a future reduction of CO2 by g-C3N4-based catalysts is predicted.

Abstract
1. Introduction
2. Experimental Procedure
    2.1 Solvothermal method
    2.2 Thermal polymerization method
    2.3 Electrochemical deposition method
3. Results and Discussion
    3.1 g-C3N4 morphology control and reduction ofCO2
    3.2 Non-metal doped g-C3N4 to reduce CO2
    3.3 Metal doped g-C3N4 to reduce CO2
    3.4 Oxide composites/g-C3N4 reduction to CO2
4. Conclusion
References

• Wei-Qin Cai(Key Laboratory of Functional Molecule Design and Interface Process, Anhui Jianzhu University)
• Feng-Jun Zhang(Key Laboratory of Functional Molecule Design and Interface Process, Anhui Jianzhu University/Anhui Key Laboratory of Advanced Building Materials, Anhui Jianzhu University) Corresponding author
• Cui Kong(Key Laboratory of Functional Molecule Design and Interface Process, Anhui Jianzhu University)
• Chun-Mei Kai(Key Laboratory of Functional Molecule Design and Interface Process, Anhui Jianzhu University)
• Won-Chun Oh(Department of Advanced Materials Science & Engineering, Hanseo University, Seosan 31962, Republic of Korea)