A comprehensive review on recent progress in synthesis methods of ZnO/CuO nanocomposites and their biological and photocatalytic applications

In recent years, ZnO and CuO nanoparticles (NPs) are the most often utilized metal oxide semiconductor NPs in a variety of applications. Even though in contrast to other distinct semiconductor metal oxide NPs, the combination of these two NPs has garnered noteworthy attention for the development of ZnO/CuO nanocomposite (NCs) owing to its extensive application throughout numerous domains. The mixing of ZnO and CuO gives control over their structural, morphological, and surface features. Since copper can readily overlap d-electrons with ZnO valence bond, it is chosen to interact with ZnO. As a result, the optical and electrical characteristics are strengthened by enhanced surface area, smaller particle sizes, and the production of ZnO/CuO NCs. Therefore, the main purpose of this review is to provide various synthesis methods like deposition, hydrothermal, co-precipitation, sol-gel, wet impregnation, spray pyrolysis and others including green synthesis protocols and explores the biocompatibility and antibacterial properties of ZnO/CuO NCs and evaluates its photocatalytic performance in the degradation of pollutants and the review identifies the current challenges such as stability, scalability and environmental impacts and suggest future research gaps for researchers and the scientific community to optimize the performance and broaden the application of the ZnO/CuO NCs.