Dual-Defect Modified 2<i>D</i>/2D TiO₂/g-C₃N₄ Heterojunction for Photocatalytic H₂ Production

In order to solve the current energy and environmental crisis, the design of efficient catalyst materials is a highly effective solution. In this paper, the photocatalytic performance of TiO2/g-C3N4 composites was improved by regulating their microstructure, such as by constructing nanosheet structures, defect sites, and contact interfaces. Although TiO2 had limited activity in H2 production under visible light irradiation, it could serve as an electron acceptor of g-C3N4, and it greatly increased the photocatalytic activity of g-C3N4. The optimal TiO2/g-C3N4 composite showed good photocatalytic performance (436.3 μmol h–1 g–1), which was 23.8 and 3 times that of T400 and g-C3N4, respectively. The increased photocatalytic activity of the TiO2/g-C3N4 composite could be attributed to the higher separation rate of the photogenerated charge carriers (PCCs), more active sites for the reaction, and a lower energy barrier than that of g-C3N4. Through many characterization and testing technologies, this work deeply studies the relationship between the fine structure and reaction mechanism of 2D/2D TiO2/g-C3N4, providing a new direction and understanding for the design and development of 2D materials with highly efficient activity.