To investigate the stability of the In

UV–vis diffuse reflectance FG2216 spectrum (DRS) over a wavelength range between 200 and 1000 nm was recorded to explain the UV–vis light photocatalytic property of In2S3. As shown in Fig. 5a, the In2S3 nanoparticles show significant absorption up to the visible range of over 650 nm, which almost covers the entire visible region. The very broad light absorption region is the main reason for its high UV–vis-light photocatalytic activity.