Three-Dimensional Highly Porous MoS2/Graphene Aerogel for Visible-Light-Driven Photocatalytic Degradation of Tetracycline

Composite aerogels are an exciting new class of porous photocatalysts, attributed to their extremely lightweight, impressive specific surface area, ease of application, and convenience of retrieval after the decontamination process. Herein, an extremely lightweight and highly porous molybdenum disulfide/graphene aerogel (pMGA) has been successfully developed through a facile and scalable two-step method and comprehensively evaluated for the photocatalytic degradation of tetracycline (TC). Particularly, the influence of porosity on the reaction kinetics and percentage removal of TC is explored because of its implications in light absorption, charge separation, and transfer, as well as molecular diffusion and transport. The sample with the largest pore size exhibits a photocatalytic efficiency and degradation rate approximately 1.6 and 3.1 times greater than those of conventional MGA by providing abundantly accessible active sites for both adsorption and photocatalytic reactions. In addition, larger pore width increases the generation of electrons and holes, and thus reactive oxygen species, because of the ease of light penetration and scattering within the interconnected graphene networks and subsequent enhancement of light-MoS2 interactions. Furthermore, the promising photocatalytic performance of pMGA in both municipal wastewater and hospital wastewater highlights its tremendous potential as a photocatalyst for visible-light-assisted decontamination of pharmaceutical micropollutants from aquatic systems.