Controlled hydrothermal synthesis and solar light photocatalysis properties of branched Bi2S3/TiO2 nano-heterostructure

In this work, we used two simple and inexpensive hydrothermal steps to synthesize Bi2S3 nanoflowers branched on TiO2 nanorod heterostructure. The nanoscale morphology of Bi2S3 deposited on TiO2 nanorods was optimized by controlling the hydrothermal growth temperature of bare Bi2S3 nanoparticles. Under solar lighting, the structural and optical properties, also the photocatalytic performance was systematically evaluated for the bare Bi2S3, bare TiO2 and Bi2S3/TiO2 heterostructures synthesized under optimized conditions. The Bi2S3/TiO2 heterostructures showed an enhanced visible-light absorption ability and photocatalytic efficiency comparing to bare TiO2. Photoluminescence and electrochemical impedance spectroscopy measurements suggest that Bi2S3/TiO2 heterostructures promoted the separation of electron-hole pairs and then enhanced the photocatalytic degradation performance for organic pollutant. The prepared heterostructures showed great stability and reusability. It also displayed enhanced photocatalytic performance for MB degradation, presenting 90% removal efficiency for 240 min, under solar light irradiation. The improved photocatalytic performance was attributed to the large Bi2S3 nanowires branched like nanoflowers structure on TiO2 nanorod arrays. This performance has obviously led to a better separation of electron-hole pair and an improvement in the absorption of light in the visible-light region.