Trends in green reduction of graphene oxides, issues and challenges: A review

Graphene has occupied the central stage in material science research all over the world. Various techniques and methods have emerged, the most common being top down approach, where graphene is synthesized from graphite. In this approach, reduction of graphene oxide is considered as the most important step and it is generally achieved by strong chemical reducing agents such as NaBH4 and hydrazine hydrate. But now, new generation of researchers have developed various natural and eco-friendly methods of reducing graphene oxide. This review summarizes the green methods employed in natural reduction of graphene oxide, which includes use of biomolecules, microorganisms and plant extracts. Issues and challenges are raised to provide pathways for future endeavors that will translate into service delivery for the benefit of human.