Facile synthesis of heterojunctioned ZnO/Bi2S3 nanocomposites for enhanced photocatalytic reduction of aqueous Cr(Vi) under visible-light irradiation

Abstract

Heterojunctioned ZnO/Bi2S3 nanocomposites were prepared via a facile solvothermal method. The obtained photocatalysts were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and Photoelectrochemical and Photoluminescence spectroscopy (PL), respectively. The results showed that ZnO/Bi2S3 composites exhibited the sandwiched-like structure, where ZnO nanoparticles were randomly embedded between Bi2S3 nanoflakes. The performance of photocatalytic Cr(VI) reduction under visible light indicated that ZnO/Bi2S3 composites exhibited high-efficiency photocatalytic activity in comparison with either Bi2S3 or ZnO. The 5%-ZnO/Bi2S3 photocatalyst removed 96% of Cr(VI) within 120 min at 20 mg/L initial concentration of Cr(VI). The enhanced performance of ZnO/Bi2S3 photocatalysts could be ascribed to the increased light harvesting and the effective separation and transfer of the photogenerated charge carriers across the heterojunction interface of the ZnO/Bi2S3 composite. This work could pave the way for the design of new hetero-structured materials and has great potential in environmental remediation.