Dual-Function Nanocomposites: CuS@ZnO P–N Heterojunctions for Enhanced Light-Driven Photocatalysis and Microbial Inactivation

Organic dyes pose significant environmental and health concerns, including increased carcinogenicity and detrimental effects on photosynthesis due to elevated levels of BOD and COD. Herein, a hydrothermal approach was employed to synthesize CuS@ZnO nanocomposites. Structural properties of the prepared nanocomposites were confirmed and evaluated by using XRD and FTIR techniques. Morphological characteristics and particle size (showing an average size of around 40 nm) were evaluated by FESEM. To assess their effectiveness, the prepared nanomaterials were investigated against the photodegradation of rhodamine B (RhB). The CuS@ZnO-b composite, with a 1:1 M ratio, achieved an impressive 94.31% photodegradation efficiency against 10 ppm RhB with a quantum yield of 1.97 × 10⁻⁵ molecules photon⁻¹ (within 120 min at pH 4.0, 50-W light intensity and 40°C). The ability of the CuS@ZnO photocatalyst to absorb visible light effectively and generate free radicals was significantly enhanced by increased photon energy activation. The antimicrobial effectiveness of the CuS@ZnO nanocomposite was tested against two bacterial strains, Lactobacillus and Escherichia coli, using the agar disk diffusion technique. The nanocomposites showed excellent antimicrobial activity, producing inhibition zones of 18 mm for Lactobacillus and 19 mm for Escherichia coli, demonstrating their strong potential to combat these bacteria. These findings underscore potential advancements in photocatalytic systems for water purification applications.