Defect Engineering in Graphitic Carbon Nitride Nanotextures for Energy Efficient Solar Fuels Production: A Review

Excessive release of greenhouse gas carbon dioxide (CO2) into the atmosphere and continuous utilization of fossil fuels has resulted in global warming and energy shortage. Among the different alternatives, photocatalytic conversion of CO2 to fuels and hydrogen production is a promising approach. To achieve this goal, highly efficient and low-cost semiconductor are demanding to maximize solar energy conversion to renewable fuels. In this perspective, metal free two-dimensional (2D) graphitic carbon nitride (g-C3N4) has attracted numerous considerations because of its low cost and higher reduction potential, but it has a lower efficiency. Herein, we demonstrated various engineering defect strategies in g-C3N4 to promote photocatalytic efficiency under solar energy. Initially, an overview of engineering defects, creation of different vacancies in g-C3N4, and their identification is discussed. In the main stream defect, engineering such as carbon, nitrogen, and oxygen to promote g-C3N4 photocatalytic efficiency is systematically disclosed. Subsequently, the role of sulfur (S) and phosphorus (P) atoms in g-C3N4 to maximize CO2 reduction and hydrogen production are deliberated. The comparative analysis, efficiency enhancement, and role of defect engineering are finally discussed to get higher yields and productivities under solar energy utilization.