Preparation and characterization of ZnS:MgS nanocomposites for photocatalytic and antioxidant applications

Abstract

In the present study, the pure ZnS and MgS quantum dots (QDs) were synthesized by co-precipitation method and the ZnS:MgS nanocomposites were prepared from these QDs in the ratios, 4:1, 1:1 and 1:4. The synthesized nanocomposite were characterized by structural, morphological, compositional and optical by X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM), Energy Dispersive X-ray (EDAX), and UV–visible absorption techniques. The ZnS and MgS were in cubic crystalline structure with high phase purity. The average crystallite structure had been calculated as 1.8 and 4.8 nm for ZnS and MgS quantum dots, respectively. The absorption was increasing by the increase of MgS concentration in composite and the band gap is narrowing due to the compositional and size effects. The ZnS:MgS nanocomposites have been used as a photocatalyst for the reduction of methylene blue dye. Though, all the nanocomposites possessed with photocatalytic activity, ZnS:MgS (4:1) showed excellent efficiency and rapid decolourization. Moreover, reusability of these nanocomposite were analysed. The Antioxidant activity of the pure ZnS and MgS and their composites was evaluated by DPPH radical scavenging method and vitamin E (Vit. E) was used as a standard drug.