ABSTRACT
This chapter gives an insight in nanotechnology platforms and focuses on new ways or methods of synthesizing nanoparticles (NPs) mainly metal–metal oxides (MeOs). The chapter will further unfold their (NPs) effective optical and catalytic activity processes and/or applications. The present work will provide a general overview on the different types, synthesis methods, characterizations, properties, and applications of NPs. Developing highly efficient electrocatalysts for emerging technologies has attracted intense attention to the scientific community. Over the past few years, the scientific communities have been deployed to develop new and fundamentally novel chemistries that will revolutionize the field of nanotechnology and human-kind. Since its inception, the field of green chemistry has been specifically designed to mitigate or respond to the many challenges faced by the world. Green chemistry unifies concepts that include the design of novel and more environmentally-friendly experimental methods in order to replace traditional, unsustainable chemistries. Most recently, green synthesis of catalytically active metal oxide nanoparticles has become an interesting subject in nanoscience and nanotechnology. The use of plant systems has been deemed a green route and a dependable method for optically and electrochemically active biosynthesized nanoparticles, owing to its environmental friendly nature. We demonstrate bioreductive green synthesized highly crystalline nanosized ZnO, CuO, NiO nanoparticles and NiO/MgO, Cu/Cu2O/CuO/ZnO nanocomposites using plants and fruit extracts (i.e., peel extracts of Puma granatum L., Moringa extract, Aloe vera, etc.) and their activities. A mechanism of interaction is also elucidated for clear understanding of ligand–metal orientation. A study on optical and electrochemical properties resulting upon interaction of ligands with different nanocatalysts is presented. The measurements of the optical absorption properties have provided important information about structure–properties dependence, while the electrochemical measurements provide the catalytic effect of the set nano-metals.
