Fabrication of gold nanodots decorated on 2D tungsten sulfide (Au-WS2) photoanode for simultaneous oxidation of phenol and arsenic (III) from industrial wastewater

Abstract

Two dimensional (2D) photoelectrocatalysts with a tunable band gap and a large surface area have emerged in recent years for advanced oxidation processes that remove toxic compounds from wastewater. In this study, ultra-thin 2D tungsten sulfide (2D WS2) photoelectrocatalysts have been fabricated using organosulfur sources, and the resulting 2D WS2 has high chemical stability and visible light band edges. Additionally, citrate stabilized Au nanodots were successfully incorporated into the 2D WS2 nanosheets in order to reduces the charge carrier recombination. The morphology, composition, chemical state, and optical properties of the Au-WS2 photoanodes have been systematically investigated. An Au-WS2 photoanode is successfully assembled in a photoelectrochemical cell (PEC) for removing phenol and oxidizing toxic As(III) into non-toxic As(V) under visible light. The studies show that the Au-WS2 photoanode had an oxidation efficiency of 99% for phenol and 95% for As(III) under visible light illumination. Furthermore, X-ray photoelectron spectroscopy (XPS) and theoretical analyses were used to investigate the oxidation pathways of phenol and As(III). A reachability study was carried out to demonstrate that mixed synthetic wastewater containing phenol and arsenite could be used for extended periods in a practical manner. In this study, Au-WS2 photoanodes were demonstrated to be highly effective in enhancing environmental remediation using advanced oxidation methods.