Publication

Abstract : Reducing toxic pollutants using reducing agents in the presence of a catalyst is a common approach. The aim of this study is to improve ZnO's properties through cobalt ion inclusion and Ag Schottky barrier formation, which are crucial for improving the catalytic reduction potential. Thus, Co-doped ZnO/Ag (CZS) heterostructure was synthesized using a simple sol-gel combustion approach. The PVA-CZS precursor TGA-DTA thermal stability analysis result confirmed that 400 °C was found to be the temperature at which stable CZS heterostructure material was obtained. The appearance of independent silver peaks on the XRD pattern confirms the formation of a ZnO/Ag Schottky barrier. The nonexistence of a cobalt (II, III) oxide independent peak and the presence of a peak shift confirm greater solubility of cobalt ions in the ZnO lattice. The crystallite size (XRD) and particle size (TEM) for synthesized materials were found to be 9–24 nm and 30–90 nm, respectively. The formation of ZnO/Ag Schottky barrier was affirmed by the HRTEM image d-spacing analysis for ZnO (0.262 nm) and Ag (0.233 nm) crystals. The reduction of indirect DRS-UV–vis bandgap energy for CSZ (2.63 eV), compared to ZnO (3.15 eV), also supports the cobalt ion inclusion in ZnO lattice interpretation. The CZS PL spectra intensity reduction compared to ZnO confirms the presence of charge transfer through the ZnO/Ag Schottky barrier. The FESEM morphological result shows the formation of a cotton-type porous CZS heterostructure. EDS-elemental compositional and elemental mapping analysis images confirmed the presence of only expected elements with good dopant distribution on the ZnO host surface. The heterostructure showed complete 4-nitrophenol and methylene blue reduction potential within 7.5 min. Thus, cobalt inclusion and Ag heterojunction have crucial future outlooks to modify ZnO properties for industrial-level pollutant reduction applications.