Preparation of a Coal-Based MoS2/SiO2/GO Composite Catalyst and Its Performance in the Photocatalytic Degradation of Wastewater and Hydrogen Production.

Abstract

Photocatalytic degradation of wastewater and the simultaneous production of hydrogen (H2) is a green and efficient method to solve energy and environmental problems. In this paper, coal-based SiO2/GO with a stable structure was prepared by a modified Hummers oxidation method, and then, a lotus-shaped composite photocatalyst, MoS2/SiO2/GO, was prepared by in situ loading of flower cluster MoS2 from sodium molybdate reduction onto SiO2/GO. Its photocatalytic degradation of wastewater and H2 production properties were investigated while characterizing the material structure. The results show that SiO2/GO as a carrier not only ensures adequate dispersion of MoS2 but also enhances the visible-light response of the composite catalyst. In addition, it can also hinder the recombination of photogenerated electrons and holes in MoS2 and act as an electron transport channel in composite catalysts. MoS2/SiO2/GO exhibits much higher photocatalytic degradation of wastewater and H2 production capacity than MoS2: after 180 min of reaction, the CODcr removal of wastewater increased from 45.6% for MoS2 to 84.2% for MoS2/SiO2/GO and the H2 yield reached 233.4 μmol. The goal of degrading wastewater while producing H2 more economically has been tentatively achieved, although not to the extent required for industrialization.