Graphitic carbon nitride (g-C₃N₄) is an attractive photocatalyst which has appealing visible light absorption, outstanding layered porous structure, high stability and nontoxicity. Many experimental methods have been developed to modify the pristine g-C₃N₄ and enhanced photocatalytic activities have been witnessed. First-principle calculation based on density functional theory is an effective approach to investigate the structural, electronic, optical and thermodynamic properties of molecules and crystals, which provides important information to elucidate the improved photocatalytic activity of modified g-C₃N₄ at atomic or unit-cell levels, or even further, to predict the property and photocatalytic activity of experimentally un-synthesized g-C₃N₄-based photocatalysts. This review is dedicated to this important material, i.e. tri-s-triazine-based g-C₃N₄ and summarized a panorama of the major advances in the first-principle investigation. The existing challenges and future directions at the forefront of this emerging research hotpot have also been discussed.

石墨碳氮化物（gC ₃ N ₄）是一种有吸引力的光催化剂，具有吸引人的可见光吸收，出色的层状多孔结构，高稳定性和无毒性。已经开发了许多实验方法来修饰原始gC ₃ N _4，并且已经见证了增强的光催化活性。基于密度泛函理论的第一性原理计算是研究分子和晶体的结构，电子，光学和热力学性质的有效方法，它为阐明修饰的gC ₃ N ₄的改进的光催化活性提供了重要的信息。在原子或单位细胞水平上，或什至更进一步，以预测实验上未合成的基于gC ₃ N ₄的光催化剂的性质和光催化活性。这篇综述专门针对这一重要材料，即基于三s-三嗪的gC ₃ N _4，并概述了第一原理研究的主要进展。还讨论了这个新兴研究热点最前沿的现有挑战和未来方向。