Advances in biogenic synthesis of palladium nanoparticles

Green approaches for the synthesis of nanoparticles provide advantages due to the fact that green protocols are benign and environmentally friendly. Among various green recipes, biogenic synthesis of nanoparticles has recently emerged as an active area of research due to the simplicity of this method, with cost effective protocols, higher potential of reduction and low toxic effect on human health and the environment. Moreover, the biogenic reduction occurs at physiological conditions of temperature and pressure. The raw materials are easily available and therefore, the reaction can easily be scaled up. This paper presents a review to give an idea about the most reliable, cost-effective and environment friendly synthetic protocols for metal nanoparticles to control size, shape and dispersity. In this contribution, we have emphasized particularly various plants responsible, and investigated so far, for the synthesis of palladium nanoparticles. Based on the isolated compounds/metabolites such as polyols, polyphenols, flavonoids and proteins from the respective plant extracts, a correlation is established where such metabolites are linked with the biogenic syntheses of Pd nanoparticles. The present investigation and works reviewed lead us to recommend a few potential plants for the reduction of Pd²⁺ ions into Pd⁰ nanoparticles. This review not only summarizes the present literature but also highlights the potential of this field to open up new avenues for researchers.