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

Abstract

AgIn 5 S 8 /TiO 2 nanocomposite is prepared through a one-pot hydrothermal method, which is used for photocatalytic H 2 production under visible-light irradiation. The effects of AgIn 5 S 8 /TiO 2 molar ratio in the nanocomposites on the crystal phase, microstructure, optical absorption properties, and photocatalytic H 2 evolution activity are investigated comparatively. The pristine AgIn 5 S 8 shows a sharp absorption edge at ∼705 nm, corresponding to a bandgap of ∼1.76 eV, and its visible-light-driven photoactivity for H 2 production can be remarkably enhanced by coupling with TiO 2 . The AgIn 5 S 8 /TiO 2 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 AgIn 5 S 8 . The enhanced photoactivity can be ascribed to some AgIn 5 S 8 nanoparticles closely contacting the TiO 2 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 AgIn 5 S 8 toward TiO 2, which is beneficial for separating the photogenerated carriers in space and improving the photoactivity.