Graphitic carbon nitride (g-C₃N₄) has received extensive attention in the photocatalytic field because of its low cost, nontoxicity, suitable bandgap structure, and high physicochemical stability among diverse photocatalysts. However, traditional g-C₃N₄ materials prepared by the high-temperature calcination of various organic precursors generally exhibit poor crystallinity and possess numerous internal and surface defects, leading to the rapid recombination of photo-excited charges. Constructing a highly crystalline g-C₃N₄ photocatalyst, as opposed to the traditional poorly crystalline g-C₃N₄, effectively reduces internal and surface defects, facilitating efficient separation and rapid transfer of photoexcited charges. As a result, the photocatalytic performance is significantly enhanced. In this review, recent progress in highly crystalline g-C₃N₄ photocatalysts is summarized. The microstructural characteristics of highly crystalline g-C₃N₄ photocatalysts are discussed in detail. Synthetic methods for highly crystalline g-C₃N₄, such as the salt-assisted (multicomponent salt and single-component salt), template, two-step calcination method, microwave-assisted method, and others, are meticulously presented. Additionally, various modification strategies for highly crystalline g-C₃N₄, encompassing bandgap engineering, heterojunction construction, and co-catalyst modification, are presented. Subsequently, a detailed description of the photocatalytic H₂-evolution applications of highly crystalline g-C₃N₄ materials is given. Lastly, the paper concludes with a discussion on the outlook for highly crystalline g-C₃N₄ photocatalysts, aiming to offer novel insights into the design of highly efficient crystalline g-C₃N₄ photocatalysts.

石墨氮化碳(gC ₃ N ₄ )因其成本低廉、无毒、合适的带隙结构以及在多种光催化剂中较高的物理化学稳定性而在光催化领域受到广泛关注。然而，通过高温煅烧各种有机前驱体制备的传统gC ₃ N _{4材料通常结晶度较差，并且具有大量的内部和表面缺陷，导致光生电荷的快速复合。与传统的低结晶gC 3} N ₄相比，构建高结晶gC ₃ N ₄光催化剂可以有效减少内部和表面缺陷，促进光生电荷的有效分离和快速转移。结果，光催化性能显着增强。这篇综述总结了高结晶gC ₃ N _{4光催化剂的最新进展。}详细讨论了高结晶gC ₃ N ₄光催化剂的微观结构特征。详细介绍了盐辅助法（多组分盐和单组分盐）、模板法、两步煅烧法、微波辅助法等高结晶gC ₃ N _{4的合成方法。}此外，还提出了高结晶gC ₃ N _{4的各种改性策略，包括带隙工程、异质结构建和助催化剂改性。}随后，详细描述了高结晶gC ₃ N ₄材料的光催化H _{2析氢应用。}最后，本文对高结晶gC ₃ N ₄光催化剂的前景进行了讨论，旨在为高效结晶gC ₃ N ₄光催化剂的设计提供新的见解。