Integrating the Z-scheme heterojunction into a novel Ag2O@rGO@reduced TiO2 photocatalyst: Broadened light absorption and accelerated charge separation co-mediated highly efficient UV/visible/NIR light photocatalysis

Abstract

A photocatalyst with good electron-transfer property and wide spectrum response is of great interest. Herein, visible/NIR-light-driven Ag2O nanoparticles (NPs) and UV/visible-responsive reduced TiO2 nanosheets (TiO2−x NSs) anchored onto reduced graphene oxide (rGO) forming Ag2O@rGO@TiO2−x composites are synthesized in this study. The as-synthesized Ag2O@rGO@TiO2−x composites exhibit a superior full solar spectrum (UV, visible and NIR) response, showing their potential for effective use of solar energy. Compared to single component (TiO2 NSs and Ag2O NPs) or binary composites (Ag2O@TiO2), Ag2O@rGO@TiO2−x ternary composite has exhibited improved photocatalytic activity under UV, visible, NIR and nature sunlight irradiation and excellent photostability. The outstanding photocatalytic performance of Ag2O@rGO@TiO2−x composites depends on three sides: firstly, synergistic effect among the reduced TiO2, Ag2O, and rGO improves the wide spectrum response ability; Secondly, Ag2O@rGO@TiO2−x builds a Z-scheme structure, which promotes the separation of electron/hole pairs and retains prominent redox ability; Thirdly, the electrons of Ag2O are transferred to rGO to suppress the photo-corrosion of Ag2O during the photocatalytic process and the stability of Ag2O@rGO@TiO2−x composite has been enhanced greatly.