Dual-Defect Modified 2D/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.