Experimental and Theoretical Investigation of Degradation Activity of Layered Two-Dimensional MoS2-ZnS Nanocomposites

Abstract

Commercial wastewater treatment via. eco-friendly routes are highly appreciated as a sustainable solution as per the United Nation’s Sustainable Development Goal 6 (UNSDG-6). In this article, we report a cost-effective and efficient route to treat wastewater by photocatalysis using Sunlight. Hydrothermally-synthesized MoS2-ZnS nanocomposite is used as photocatalyst and methylene blue (MB) and rhodamine B (RhB) are used as model dyes to study the photocatalytic degradation activity. After exposing to the Sunlight for a period of 60 min, the MoS2-ZnS nanocomposite shows a degradation of 98.29 and 93.01% for MB and RhB, respectively. This enhanced photocatalytic activity of the MoS2-ZnS nanocomposite is due to its high light absorption and lower electron-hole recombination for the degradation of dyes. No harmful by-products are formed, which shows the eco-friendly nature of photocatalytic degradation of dyes in wastewater. A detailed theoretical investigation is carried out using density functional theory (DFT) analysis. The DFT calculations are performed for dyes and the photocatalysts in order to understand the mechanism behind the degradation. A good correlation between the calculated and experimental data is observed. This study proclaims that MoS2-ZnS nanocomposite is a cost-effective and efficient photocatalyst among other costly layered two-dimensional nanocomposites.