ZnO/CdS nanocomposites: Synthesis, characterization and assessment of photocatalytic performance

Abstract

This study investigates the photocatalytic degradation of Methyl orange (MO) dye using ZnO/CdS nanocomposites synthesized by the hydrothermal technique. Using XRD, FTIR, FESEM-EDS, TEM, UV-Vis DRS, BET, and XPS, the chemically produced chalcogenide hybrid nanocomposites were thoroughly characterized. The 5 % ZnO/CdS nanocomposite photocatalyst exhibited a crystallite size of 5.63 nm, a bandgap energy of 2.35 eV, and a larger surface area of 118.47 m²/g, indicating excellent photocatalytic performance compared to pristine ZnO and CdS. The best MO removal efficiency of 98.67 % within 60 min is demonstrated by the 5 % ZnO/CdS photocatalyst under UV-C irradiation. The photocatalytic MO degradation reaction maintains a pseudo-first-order kinetic law. The rate constant (k) and half-life (t_1/2) are found to be 0.065 min⁻¹ and 10.66 min, respectively. The reusability of the 5 % ZnO/CdS photocatalyst was investigated, and the MO removal efficiency remained acceptable after three cycles. These findings suggest that the synthesized ZnO/CdS nanocomposite is a promising photocatalyst for efficiently and sustainably removing organic pollutants from wastewater.