Facile fabrication of MnWO4/CdS composites for visible-light-driven photocatalytic Cr(VI) reduction

A novel efficient MnWO4/CdS photocatalyst was fabricated, which had effective performance and outstanding stability of photocatalytic Cr(VI) reduction. Various characterization techniques were used to investigate the crystallographic structure, morphology, optical and electrical properties of photocatalysts. By coupling with MnWO4, the photo-absorption capacity of composites was clearly enhanced. The X-ray photoelectron spectra revealed that CdS as the electron donor excited carriers irradiated by visible light. The excellent photocatalytic performance of MnWO4/CdS composites was mainly ascribed to efficient separation and migration of carriers between CdS and MnWO4 via their intimate contact interfaces which follows a Type-II heterojunction. Under acidic conditions, the major species HCrO - 4 in K2Cr2O7 solution was easily reduced by the photogenerated electrons. This work provides a new design of MnWO4/CdS photocatalysts for more efficient utilization of solar energy and some new perspectives for environmental remediation.