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.

合适的能带结构赋予石墨碳氮化物（gC ₃ N ₄）良好的氧化还原能力和可见光响应，使其在光催化中很受欢迎。考虑到单组分gC ₃ N _4的太阳能转化为劣等离子的情况，负载助催化剂可用于提高其光催化活性。特别地，可以形成2D / 2D异质结与GC的二维（2D）的助催化剂₃ Ñ ₄脱颖而出由于几个优点，其中大面积接触接口与GC ₃ Ñ _4个占优势。此处，gC ₃ N ₄的基本信息首次介绍。然后，提出了用于增强gC ₃ N ₄的STC能量转化的代表性2D助催化剂（例如，石墨烯，石墨二炔，二硫化钼，黑磷和MXenes）。之后，gC ₃ N ₄的最重要成就以光催化析氢，二氧化碳还原，过氧化氢生成和固氮的形式描述了在STC能量转换中用2D助催化剂修饰的结构。最后，展望了用二维助催化剂修饰的光催化剂的未来发展和挑战。本文有望加深读者对光催化中2D助催化剂的理解，并重视本文所述的2D助催化剂以及许多其他未提及的催化剂。