Preparation of AgIn5S8/TiO2 Heterojunction Nanocomposite and Its Enhanced Photocatalytic H2 Production Property under Visible Light

AgIn5S8/TiO2 nanocomposite is prepared through a one-pot hydrothermal method, which is used for photocatalytic H-2 production under visible-light irradiation. The effects of AgIn5S8/TiO2 molar ratio in the nanocomposites on the crystal phase, microstructure, optical absorption properties, and photocatalytic H-2 evolution activity are investigated comparatively. The pristine AgIn5S8 shows a sharp absorption edge at similar to 705 nm, corresponding to a bandgap of similar to 1.76 eV, and its visible-light-driven photoactivity for H-2 production can be remarkably enhanced by coupling with TiO2. The AgIn5S8/TiO2 nanocomposite with molar ratio of 1:10 has the maximum photoactivity for H-2 production, improved by 7.7 times as compared with the pristine AgIn5S8. The enhanced photoactivity can be ascribed to some AgIn5S8 nanoparticles closely contacting the TiO2 nanoparticles to form heterojunction structure. This configuration of the composite photocatalyst results in an efficient charge separation at the interface, followed by fast diffusion of photoelectrons generated in AgIn5S8 toward TiO2, which is beneficial for separating the photogenerated carriers in space and improving the photoactivity.