ZnS/CdS Heterostructures for Efficient Solar‐Driven Photocatalytic Degradation of Rhodamine B

ZnS/CdS (1:4) heterostructure nanocomposite was synthesized via a facile sol–gel route and evaluated for visible‐light‐driven photocatalytic degradation of Rhodamine B (RhB) dye. X‐ray diffraction (XRD) confirmed the formation of cubic ZnS and CdS phases with an average crystallite size of ∼6.5 nm, indicating successful heterojunction formation. Fourier‐transform infrared spectroscopy (FTIR) analysis revealed characteristic metal–sulfur bonding. Specific surface area (120.34 m 2 g − 1 ), porosity, morphological, and compositional details were provided by Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). UV–vis diffuse reflectance spectroscopy (DRS) revealed enhanced visible‐light absorption, accompanied by a reduced band gap of 2.0 eV, resulting from the synergistic interaction between ZnS and CdS. Under visible‐light irradiation, the ZnS/CdS nanocomposite achieved 85% RhB degradation within 180 min, following pseudo‐first‐order kinetics with a rate constant of 0.04801 min − 1 , outperforming individual semiconductor components. The enhanced photocatalytic performance is attributed to efficient charge separation across the ZnS/CdS heterojunction and the suppression of electron–hole recombination. These results demonstrate that the engineered ZnS/CdS heterostructure is an effective visible‐light photocatalyst for the degradation of organic dyes, showing promise for wastewater treatment applications.