Constructing novel NaLiTi3O7/g-C3N4 Z-scheme photocatalysts to facilitate the separation of charge carriers and study the hydrogen production performance

Abstract

To utilize the UV and visible lights and to improve the separation of photoinduced carriers, a composite composed of NaLiTi₃O₇ and graphite-carbon nitride (g-C₃N₄) was constructed. The morphology and microscopic structural details of NaLiTi₃O₇/g-C₃N₄ photocatalyst were characterized using XRD, SEM, TEM, XPS, FT-IR, UV-DRS, and TGA techniques. XRD and SEM results showed that well-crystalline NaLiTi₃O₇ nanoparticles were well dispersed on the surface of g-C₃N₄ sheets and that the introduction of g-C₃N₄ effectively alleviated the aggregation of NaLiTi₃O₇ nanoparticles. UV-DRS results further suggested that the light absorption edge of the NaLiTi₃O₇/g-C₃N₄ composite had a significant redshift. Due to these advantages, NaLiTi₃O₇/g-C₃N₄ composites exhibited good photocatalytic performance. The hydrogen production performance of all NaLiTi₃O₇/g-C₃N₄ samples was much better than that of pure g-C₃N₄ and NaLiTi₃O₇ under solar irradiation, and the best NaLiTi₃O₇/g-C₃N₄ composite produced 18 times more hydrogen than pure NaLiTi₃O₇ and 4 times more hydrogen than pure g-C₃N₄. Compared with pure NaLiTi₃O₇ or g-C₃N₄ phases, coupling NaLiTi₃O₇ with g-C₃N₄ significantly improved the photocatalytic performance due to the formation of the heterojunction interface between them, which was favorable for the effective separation of the photogenerated electron and hole in a wide light absorption range.