Enhanced solar-to-chemical energy conversion of graphitic carbon nitride by two-dimensional cocatalysts

The appropriate band structure endows graphitic carbon nitride (g-C3N4) with benign redox ability and visible light response, resulting in its popularity in photocatalysis. Given the inferior solar-to-chemical (STC) energy conversion of single-component g-C3N4, loading cocatalysts is serviceable in advancing its photocatalytic activity. In particular, two-dimensional (2D) cocatalysts that could form 2D/2D heterojunctions with g-C3N4 stand out due to several advantages in which the large-area contact interface with g-C3N4 predominates. Herein, the basic information of g-C3N4 was first introduced. Then, representative 2D cocatalysts (e.g., graphene, graphdiyne, molybdenum disulfide, black phosphorus, and MXenes) used to strengthen the STC energy conversion of g-C3N4 were presented. Afterwards, the foremost achievements of g-C3N4 decorated with 2D cocatalysts in STC energy conversion were described in terms of photocatalytic hydrogen evolution, carbon dioxide reduction, hydrogen peroxide production, and nitrogen fixation. Finally, the future development and challenge of photocatalysts decorated with 2D cocatalysts were prospected. This paper could hopefully deepen the readers' understanding of 2D cocatalysts in photocatalysis and attach importance to 2D cocatalysts described in this paper and many others not mentioned.