Developments in green nanotechnology: biogenic synthesis, mechanisms, applications

The conventional methods for fabrication of nanomaterials have heavily relied on the use of toxic chemicals for their reduction and stabilization as well as organic solvents, which are detrimental to the ecosystem. Thus, developing sustainable synthesis methods in line with the principles of “green” chemistry has always taken foremost precedence and at the same time, been a challenge. Over the past few decades, the synthesis of nanomaterials using environment-friendly agents has captivated the research community around the globe. A variety of plant extracts and microbes have been explored for the biogenic synthesis of different nanomaterials for myriad applications. This review aims to present the synthesis of nanomaterials using various green agents, their mechanism of formation and applications. Focus is also laid on how the morphology or property of the nanomaterials is influenced by different green agents or conditions during synthesis. Finally, the challenges and scope of using green agents for the synthesis of nanomaterials are presented. • Biogenic synthesis of nanomaterials with plant extracts and microbes is reviewed. • Insights into underlying mechanisms are investigated. • Applications in catalysis, biomedicine, environmental remediation are explored. • Challenges and recommendations in biosynthesis are presented.