Eco-friendly synthesis of Ag-doped ZnO/MgO as a potential photocatalyst for antimicrobial and dye degradation applications

The world has been witnessing a rapid surge in environmental issues, and to combat this situation, researchers have been exploring the potential of nanomaterials-based solutions. Among these, photocatalytic nanomaterials (PNMs) and nanocomposites (NCs) synthesized using plant extracts have caught the recent attention of scientists. Our team was intrigued by this trend and sought to create an eco-friendly solution utilizing PNMs and NCs synthesized through plant extracts. Plants are a rich source of biomolecules that aid in the production of PNMs and their NCs for a diverse range of environmental applications. The resulting bio-synthesized PNMs/NCs are not only cost-effective and non-toxic, but also safe to handle and highly stable compared to other synthesis methods. While significant efforts have been made to create a greener and more affordable technology for the synthesis of PNMs/NCs, the challenge has been to extend the photocatalytic response to the visible light spectrum as opposed to just the UV spectrum, which represents only 6% of the total solar spectrum. Fortunately, the presence of special pigments in plant extracts facilitates the transport of electrons and holes, allowing for improved e− and h+ transfer rates and charge carrier separations. The present review primarily focuses on the biosynthesized PNMs (Ag, MgO, and ZnO-based) and their NCs, examining their shape, size, and various antimicrobial and dye degradation applications. We also explore efficient green approaches for synthesis methods and compare them to pre-established physical and chemical processes. We hope that this review sheds light on the fundamental mechanisms behind photocatalyst interaction with bacteria and the basic synthesis and fabrication mechanisms for PNMs and NCs, ultimately leading to a better understanding and future research for the scientific community.