Decoration of ZnO surface with tiny sulfide-based nanoparticles for improve photocatalytic degradation efficiency

Modifying wide band gap ZnO nanoparticles surface by combine narrow bandgap semiconductors is a novel route to promote the ZnO to diverse applications. Herein, different metal sulfides (CdS, Ag₂S and Bi₂S₃) were decorated on ZnO surface using facile a chemical route for photocatalytic application. Crystal structure, surface morphology and optical changes for the surface modified ZnO were studied by using various characterization techniques. The XRD spectra exhibited mixed phase of decorated metal sulfide nanoparticles along with strong pattens of hexagonal structure ZnO. The SEM images were confirmed that tiny CdS, Ag₂S and Bi₂S₃ sulfide nanoparticles are well decorated on ZnO hexagonal rods surface. Band gap of the ZnO was tuned into visible region by modifying the surface by the sulfide nanoparticles. Textile industry-based crystal violet (CV) dye was used as a model pollutant to evaluate the photocatalytic activity of sulfides decorated well-crystalline ZnO photocatalysts under natural sunlight. Among the three catalysts, the Ag₂S decorated ZnO achieved greatest photodegradation efficiency of 94.1% for degradation of the CV dye with rate constant value of 0.050. The highest catalytic activity may be related to Ag₂S acting a significant part in reducing bandgap and boosting hole, superoxide radical, and hydroxyl radical formation, which inhibits recombination, hence enhancing the photocatalyst's efficacy, activity, and also stability.