Heterostructures based on g-C3N4 for the photocatalytic CO2 reduction

The interest of the global scientific community in the problems of CO2 utilization and returning to the carbon cycle has markedly increased in recent years. Among various CO2 transformation processes, photocatalytic reduction is one of the most promising. Currently, much attention is paid to photocatalysts based on graphitic carbon nitride, since the use of g-C3N4 makes it possible to perform CO2 reduction under visible or solar light irradiation. To increase the reduction efficiency, g-C3N4 is subjected to various modifications with the most popular and promising approach being the synthesis of composite photocatalysts based on g-C3N4 with other semiconductors to form heterostructures. Depending on the type of semiconductor, transfer of photogenerated charge carriers in these systems can occur by various mechanisms, which largely determine the course of the process and the rates of formation of reaction products. This review addresses studies on the synthesis of composite photocatalysts based on g-C3N4, with emphasis being placed on the mechanisms of charge carrier transfer and the distribution of products of CO2 reduction.