ZnTe/CdS Heterojunctions as High‐Performance Visible‐Light Catalysts for Rapid and Sustainable Organic Dye Degradation

ABSTRACT The present study focuses on the synthesis, characterization, and catalytic performance of ZnTe, CdS, and ZnTe/CdS nanocomposites for the reductive degradation of Congo Red (CR) and Rhodamine‐B (RhB) dyes. The nanostructures were prepared via a solvothermal synthesis route, to yield phase‐pure materials with well‐defined morphology and crystalline. Several characterization methods viz UV–visible (vis) spectroscopy, Photoluminescence (PL) spectroscopy, x‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy‐dispersive x‐ray spectroscopy (EDX) confirmed the successful formation of the composites with homogeneous elemental distribution. PL studies unveil that the formation of heterojunction structure of ZnTe/CdS by with a band gap of 2.32 eV exhibit an emission peak at 629 nm which is the amalgamation of electronic structures from both constituents and efficient interfacial charge transfer. Furthermore, room temperature catalytic reduction experiments were conducted on CR, RhB by the synthesized nanomaterials and it was revealed that reactions followed pseudo‐first‐order kinetics. The reduction results indicated that CR dye was removed 74% by ZnTe/CdS in 100 min and 99.5% of the RhB was removed by ZnTe/CdS in 65 min. These results are much superior, than the individual components and also the effect of composite was further confirmed by physical mixing of the individual components. This improvement may be attributed to the synergistic effect of nanocomposites that facilitates the electron transfer. Further, the reusability studies confirm the developed nanomaterials have shown the efficiency was retained until three cycles. These findings indicate that ZnTe/CdS nanocomposites are promising catalysts for the rapid and efficient reductive removal of hazardous dyes from wastewater.