Introducing sulfur vacancies and in-plane SnS2/SnO2 heterojunction in SnS2 nanosheets to promote photocatalytic activity

Abstract

Due to the relatively sluggish charge carrier separation in metal sulfides, the photocatalytic activity of them is still far lower than expected. Herein, sulfur vacancies and in-plane SnS2/SnO2 heterojunction were successfully introduced into the SnS2 nanosheets through high energy ball-milling. These defective structures were studied by the electron paramagnetic resonance, Raman spectra, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscope analyses. The sulfur vacancies and in-plane heterojunctions strongly accelerate the separation of photoexcited electron-hole pairs, as confirmed by the photoluminescence emission spectra and time-resolved photoluminescence decay spectra. The introduction of sulfur vacancies and in-plane heterojunction in SnS2 nanosheets results in roughly six times higher photodegrading rate for methyl orange and four times higher photocatalytic reduction rate of Cr6+ than those of pure SnS2 nanosheets.