Impact of Heterovalent Cu<sup>2+</sup> and Ag<sup>+</sup> Doping on the Structural, Optoelectronic, and Photocatalytic Properties of ZnO for Enhanced Solar-Driven Hydrogen Evolution and Organic Pollutant Degradation
Saedah R. Al‐Mhyawi, Ahlam I. Al‐Sulami, Fatimah Mohammad H. AlSulami, Reema H. Aldahiri, Merfat M. Alsabban, Fuad Mohammed A.B. Mosa, Jawza Sh Alnawmasi, Omer Nur, A. Rajeh, Mohammed A. Mannaa
Abstract
High Resolution Image Download MS PowerPoint Slide 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.