Dual-Defect Modified\n2<i>D</i>/2D TiO<sub>2</sub>/g‑C<sub>3</sub>N<sub>4</sub> Heterojunction for Photocatalytic\nH<sub>2</sub> Production

In order to solve the current energy and environmental\ncrisis,\nthe design of efficient catalyst materials is a highly effective solution.\nIn this paper, the photocatalytic performance of TiO<sub>2</sub>/g-C<sub>3</sub>N<sub>4</sub> composites was improved by regulating their\nmicrostructure, such as by constructing nanosheet structures, defect\nsites, and contact interfaces. Although TiO<sub>2</sub> had limited\nactivity in H<sub>2</sub> production under visible light irradiation,\nit could serve as an electron acceptor of g-C<sub>3</sub>N<sub>4</sub>, and it greatly increased the photocatalytic activity of g-C<sub>3</sub>N<sub>4</sub>. The optimal TiO<sub>2</sub>/g-C<sub>3</sub>N<sub>4</sub> composite showed good photocatalytic performance (436.3\nμmol h<sup>–1</sup> g<sup>–1</sup>), which was\n23.8 and 3 times that of T400 and g-C<sub>3</sub>N<sub>4</sub>, respectively.\nThe increased photocatalytic activity of the TiO<sub>2</sub>/g-C<sub>3</sub>N<sub>4</sub> composite could be attributed to the higher\nseparation rate of the photogenerated charge carriers (PCCs), more\nactive sites for the reaction, and a lower energy barrier than that\nof g-C<sub>3</sub>N<sub>4</sub>. Through many characterization and\ntesting technologies, this work deeply studies the relationship between\nthe fine structure and reaction mechanism of 2<i>D</i>/2D\nTiO<sub>2</sub>/g-C<sub>3</sub>N<sub>4</sub>, providing a new direction\nand understanding for the design and development of 2D materials with\nhighly efficient activity.