ABSTRACT
This chapter discusses the challenge, pros, and cons, necessitate green synthesis and its multifunctional applications. Importantly covered, synthetic processes of MNPs using green natural products alike plant extracts and micro-organisms such as algae, bacteria, fungi, etc. Besides, the various parameters like concentration, pH, reaction time, temperature, and so on affect the green synthesis of MNPs are also explained. In exploring various options to address the above problem, nanomaterials, like metal nanoparticles, have emerged as promising material since; NPs possess greater permanence, lower toxicity, higher stability and selectivity when compared to organic NPs, drugs and chemicals agents. Owing to differences in the preparation conditions of the NPs, alike precursors, reactants, processing temperature and pH. Metal oxide based nanomaterials with extraordinary characteristics have been proposed, prepared, and used as main materials in the field of photocatalysis and biomedicine, due to their non-toxic nature, large specific surface area, useful optical band gap, and high biological activity.
