Abstract
The preparation of photocatalysts capable of harnessing solar light energy as a sustainable and renewable source for treating wastewater containing organic pollutants and for H(2) production from water splitting represents a significant direction in the photocatalyst field. In this study, S-scheme CuO/Ag(2)O-ZnO heterostructures with different CuO contents were prepared by the sol-gel method. XRD results confirmed the doping of ZnO by Ag(+) and Cu(2+). Also, the intensity of peaks decreased obviously after the addition of Ag(+), while the addition of Cu(2+) was accompanied by an increase in the peak intensity. UV-visible analysis results displayed a significant red shift of the absorption edge to the visible region, and a remarkable reduction in the band gap of ZnO was detected after the addition of Ag(+) and Cu(2+). The photocatalytic performance was evaluated by photodegradation of MB, TC, and H(2) evolution under sunlight illumination. The results revealed that the addition of Ag(+) and Cu(2+) enhanced the photocatalytic activity of ZnO significantly due to the formation of the S-scheme (p-n)-heterojunction heterostructure, which efficiently improved the separation and increased the lifetime of the photogenerated charge carriers compared with pure ZnO nanoparticles. The ESR and radical quenching results revealed that (•)O(2) (-) and (•)OH are the active radicals in the photodegradation of methylene blue (MB) and tetracycline (TC). The photodegradation mechanism, mineralization (TOC), and kinetic degradation were studied. The CuO/Ag(2)O-ZnO heterostructure exhibited excellent photocatalytic activity, reusability, and stability.