Zinc oxide nanostructures: review on the current updates of eco-friendly synthesis and technological applications

Abstract

The global community faces significant challenges in energy and the environment. Scientists and engineers have developed innovative techniques in nanotechnology and material science, particularly in eco-friendly synthesis of metal oxides, to address these challenges. This review discusses current trends in eco-friendly synthesis and technological applications of ZnO nanostructures beyond the biomedical field mostly presented in the literature. Green synthesis methods of ZnO have attracted researchers due to their low toxicity, versatility, and environmentally friendly nature. ZnO nanoparticles (NPs) possess unique optical and thermal characteristics, a wide band gap, high excitation binding energy, and GRASE status, contributing to their broad range of applications. Conventional synthesis methods were reported to have potential toxicity effects, while green synthesis offers recognized advantages. The review also explores the mechanism of ZnO NP formation. Moreover, this review provides an overview of diverse applications of ZnO NPs, including energy devices (solar cells), cement concrete, sensors, water and environmental remediation, enhanced oil recovery (EOR), coolants and biomedical. Further studies are recommended to explore additional properties and applications of ZnO NPs using the latest environmentally friendly approaches.