Fabrication of novel ZnO/MnWO4 nanocomposites with p-n heterojunction: Visible-light-induced photocatalysts with substantially improved activity and durability

Abstract

We report, for the first time, binary ZnO/MnWO4 nanocomposites with p-n heterojunction fabricated by a simple ultrasonic-calcination route. The phase structure, morphology, and optical along with textural properties were comprehensively characterized. The photocatalytic performance was studied via degradations of rhodamine B, methyl blue and methyl orange (RhB, MB, MO), and fuchsine pollutants under visible-light illumination. The ZnO/MnWO4 nanocomposites exhibited better photocatalytic performance than their single components and the nanocomposite with 30 wt% MnWO4 showed the highest activity. Photocatalytic performance of this nanocomposite is 22.5, 17.7, 26.8, and 23.9 times higher than that of the ZnO sample in degradations of RhB, MB, MO, and fuchsine dyes, respectively. The improved photocatalytic performance was ascribed to the formation of p-n heterojunction between ZnO and MnWO4 with high charge separation efficiency as well as strong visible-light absorption ability. The possible mechanism for the improved photocatalytic performance was proposed. This study revealed that the novel ZnO/MnWO4p-n heterojunction can act as a promising visible-light-active photocatalyst for environmental applications.