Enhancement of the photocatalytic activity of fabricated ZnS nanoparticles in the photodegradation of methylene blue

Abstract

Abstract This paper first aims to synthesize and characterize ZnS nanoparticles (NPs) by the hydrothermal method. The synthesized NPs are investigated by x-ray diffraction (XRD), field emission electron microscopy (FE-SEM), energy-dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), ultraviolet-visible (UV–vis) spectroscopy, N2 adsorption-desorption, diffuse reflectance spectroscopy (DRS). Thiosemicarbazide/Zinc acetate dehydrate/ Ethylenediamine/Deionized water are utilized as precursors with three molar ratios and labeled as S1 = 2:1:1:1, S2 = 2:1:1:3 and S3 = 1:2:2:2, respectively. The synthesized pure ZnS NPs under UV irradiation present a higher photodegradation rate in comparison with the existing pure and doped ZnS-based ZnS. The direct optical bandgap of S1, S2 and S3 are estimated by the DRS method and approved by the Tauc method as 3.29 eV, 3.38 eV and 3.37 eV, respectively. The photocatalytic activities of the synthesized pure NPs (S1, S2 and S3) are calculated to be 0.044, 0.036 and 0.050 min−1, respectively. The results indicate the significant effect of precursors on the crystallite phase, optical bandgap and photocatalytic activity of the ZnS NPs so that in comparison with other studies, they could be an effective candidate in the field of photodegradation of the organic dyes.