Regulation of Polymerization Kinetics to Improve Crystallinity of Carbon Nitride for Photocatalytic Reactions

• Published in: ChemSusChem 2023-08, Vol.16 (16), p.e202300361-n/a
• Main Authors: Wang, Chong, Xiao, Hongxiang, Lu, Yichun, Lv, Jinliang, Yuan, Zhanhui, Cheng, Jiajia
• Format: Article
• Language: English
• Subjects: Ammonia; Carbon; Carbon nitride; Catalytic activity; Copper oxides; Crystal structure; Crystalline; Crystallinity; Crystallography; Current carriers; High temperature; Hydrogen production; Kinetics; Melamine; Photocatalysis; Polymerization; Polymerization kinetics
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202300361

Carbon nitride (CN) polymers exhibit tunable and fascinating physicochemical properties and are thus an essential class of photocatalytic materials with potential applications. Although significant progress has been made in the fabrication of CN, the preparation of metal‐free crystalline CN via a straightforward method remains a considerable challenge. Herein, we describe a new attempt to synthesize crystalline carbon nitride (CCN) with a well‐developed structure through regulation of the polymerization kinetics. The synthetic process involves the pre‐polymerization of melamine to remove most of the ammonia and further calcination of the pre‐heated melamine in the presence of copper oxide as an ammonia absorbent. Copper oxide can decompose the ammonia produced by the polymerization process, thereby promoting the reaction. These conditions facilitate the polycondensation process while avoiding carbonization of the polymeric backbone at high temperatures. Owing to the high crystallinity, nanosheet structure, and efficient charge‐carrier transmission capacity, the as‐prepared CCN catalyst shows much higher photocatalytic activity than its counterparts. Our study provides a novel strategy for the rational design and synthesis of high‐performance carbon nitride photocatalysts by simultaneously optimizing polymerization kinetics and crystallographic structures. Highly crystalline carbon nitride (CCN) was effectively fabricated by controlling the condensation kinetics of the polymerization process. Our finding not only demonstrates that CCN is a promising catalyst for photocatalytic reactions but also highlights an underdeveloped avenue to synthesize carbon nitride with high crystallinity.