Binary CuO/ZnO Nanocomposites: A Mini-Review on Synthesis, Properties, and Emerging Applications

Abstract

In the fields of energy conversion, storage and also in environmental remediation, metal oxides nanocomposites are the emerging and promising materials with a plethora of applications in the essayed fields of catalysis, sensing, hydrogen storage, energy conversion, optoelectronics, and environmental remediation. Therefore, they encompass the entirety of sustainability and energy conversion. Metal oxide nanocomposites such as copper oxide/zinc oxide (CuO/ZnO) are of tremendous interest due to the ease with which their catalytic, electrical, optical, magnetic, biodegradable and biocompatible properties can be modified. The composite of CuO and ZnO gives a distinct composite with heterogenous grains of higher surface area, more active sites, facilitated electron transfer, and reduced photo-corrosion which results in high performance. CuO/ZnO nanocomposites have been prepared via different synthesis routes such as co-precipitation, sol–gel, wet impregnation, and thermal decomposition. Hydrothermal and microwave-assisted methods have emerged as some of the most promising synthesis methods due to their added control over the particle shape. Depending on the synthesis route and conditions, composites may appear as Cu-doped ZnO or as mixed CuO/ZnO oxides with varied morphologies including nanoparticles (0D), nanorods (1D) and hierarchical structures. Various advanced Characterization methods have also been employed in determining the properties of the synthesized nanocomposite such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Uv-Vis spectroscopy. This review is dedicated to the discussion of synthesis methods, properties, and the wide spectrum of the applications, especially photocatalysis, sensing, and energy devices, along with the mention of the challenges and progress of the future realization.