Photocatalytic reduction of CO₂ is known as one of the most promising methods to produce valuable fuels and value-added compounds. To overcome selectivity and efficiency downsides, various photocatalysts have been designed and developed. This review discusses the state-of-the-art in photo-conversion of CO₂ over graphitic carbon nitride (g-C₃N₄)-based composites. The modification strategies to improve photocatalytic activity of g-C₃N₄ were classified into different categories and discussed as structural modifications, elemental doping, copolymerization, fabricating heterojunctions between g-C₃N₄ and other semiconductors, Z-scheme heterojunctions, noble metal/g-C₃N₄ photocatalysts, and design of ternary nanocomposites based on g-C₃N₄. Finally, perspectives and future research works in this field were also outlined.

光催化还原CO ₂是生产有价值的燃料和增值化合物的最有前途的方法之一。为了克服选择性和效率的缺点，已经设计和开发了各种光催化剂。这篇综述讨论了在基于石墨氮化碳（gC ₃ N ₄）的复合材料上CO _2的光转化的最新技术。改善gC ₃ N _4的光催化活性的修饰策略分为不同类别，并讨论为结构修饰，元素掺杂，共聚，在gC ₃ N ₄之间形成异质结。和其他半导体，Z型异质结，贵金属/ gC ₃ N ₄光催化剂，以及基于gC ₃ N ₄的三元纳米复合材料的设计。最后，还概述了该领域的观点和未来的研究工作。