CuO-decorated ZnO nanosheets with enhanced dielectric characteristics and visible light-driven photocatalytic activity towards organic pollutants

ZnO-CuO nanocomposites ((CuO)x(ZnO)1-x) have been prepared by the facile co-precipitation method. The prepared nanocomposites have been studied using XRD, SEM, UV–Vis, FTIR, Raman, and dielectric measurements. XRD characterization depicts the formation of hexagonal and monoclinic structures of ZnO and CuO, respectively. SEM studies of the nanocomposites show that ZnO has sheet-like design while CuO has rod like morphology. The FTIR and Raman studies reveal the presence of characteristic starching and bending modes of ZnO and CuO nanostructures with plenty of surface-related defects in the nanocomposites, respectively. Interestingly, the optical band gap of the nanocomposite is red shifted towards the visible range of the solar spectrum with the increased loading of CuO over the surface of the ZnO nanosheets. The enhancement in the dielectric characteristics has also been observed, which may be due to the increased number of interfaces and electron exchange between Zn2+ and Cu+2 ions in the nanocomposites. Furthermore, the photodegradation capability of the prepared nanocomposites has been examined towards methyl orange (MO), an azo dye with a highly stable and toxic nature, mostly found in wastewater from textile industries. The results show that the nanocomposites exhibit appreciable photocatalytic activity (71% dye decomposition in 180 min) under visible light irradiation, which can be ascribed to the enhanced visible light response of the nanocomposites, high specific surface area of the composite, and optimized pH conditions of dye solution. The prepared nanocomposite may find applications in barrier layer capacitors and wastewater treatment technologies.