Diatomite-Bi2S3 composite photocatalyst: enhanced photocatalytic performance for visible light reduction of Cr(VI)

The Cr(VI) is a acute toxic and bioaccumulated pollutant in wastewater, the removal of these contaminants is particularly significant. Semiconductor photocatalysis is an effective method to reduce the Cr(VI) in the wastewater. In this paper, diatomite/Bi2S3 composite photocatalysts are synthesized by a facile in suit hydrothermal vulcanization method using bismuth nitrate and thiourea as precursors and diatomite as supporting materials. The structural information, morphologies, chemical states and optical properties of the composite are characterized by XRD, SEM, XPS and DRS. Under visible light irradiation (lambda > 400 nm), the diatomite/Bi2S3 composite exhibit better photocatalytic reduction activity of Cr(VI) than the pristine Bi2S3. The photocatalytic mechanism is further investigated by the active species capturing tests and photoelectrochemical measurements.