Chemical Approach Based ZnS-ZnO Nanocomposite Synthesis and Assessment of their Structural, Morphological and Photocatalytic Properties

This work describes a comparative assessment between zinc oxide (ZnO) nanoparticles (NP), zinc sulfide (ZnS) NP and ZnS-ZnO nanocomposite (NC). A chemical non-aqueous method was chosen for materials synthesis. From XRD spectra, the crystalline phases and phase purity of the samples were confirmed. The average crystallite sizes were calculated as 69 nm, 5 nm and 10 nm for ZnO NP, ZnS NP and ZnS-ZnO NC, respectively, indicating a relatively pronounced growth and coarsening processes in ZnO NP. The lowering of band gap energy was verified through optical absorption spectra of ZnS-ZnO NC. Morphological investigation revealed that ZnO consisted of plate-like structures, ZnS comprised of agglomerated spheres while ZnS-ZnO NC exhibited both these structures. EDX and XPS spectra of ZnS-ZnO NC confirmed the presence of Zn, S and O in the NC. The photocatalytic degradation of cationic dyes were observed to be the highest by ZnS-ZnO NC compared to its individual components, ZnO and ZnS.