Structural, optical and photocatalytic properties of ZnS/zeolite Y nanoparticles synthesized by γ-ray irradiation

The present study deals with würtzite ZnS nanoparticles embedded in zeolite Y, synthesized by γ-radiolysis of exchanged zeolite ZnY in the presence of 2-mercaptoethanol (RSH). The nanocomposites were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible absorption, and photoluminescence (PL). Compared to the bulk state, ZnS nanocrystals have blue – shifted UV visible absorption with an excitonic peak situated at around 320 nm. They display a wide photoluminescence band with seven peaks in the range of 320–550 nm. The increase of the irradiation dose and RSH concentration results in a growth the ZnS nanocrystals and improves their optical performances. The optical as well as the structural characterizations confirmed the nanometric size of ZnS particles (Φ = 5–18 nm). When tested in photodegradation of Congo red under sun light, ZnS-zeolite Y catalyst exhibit high efficiency. For the experimental conditions: [ZnS-Y] = 0.5 g L−1; [CR] = 10 mgl−1+; pH = 6.6, the pseudo-first order constant is 0.076 min−1.