Transforming waste into carbon-based nanomaterials

Carbon-based nanomaterials (CNMs) such as graphene and carbon nanotubes (CNTs) have huge potential in environment and energy related applications. Although a wide range of synthesis methods has been developed to produce CNMs, green synthesis methods with either energy-saving reactions or inexpensive starting materials are gaining more attentions recently. It is evident from recent developments that converting low-valued waste materials into high-valued CNMs contributes towards sustainable materials processing and recycle technology. Objective of this review is to analyze green synthesis routes to prepare CNMs focusing on graphene and CNTs. This review starts with the identification of wastes that can be used as resources for producing CNMs followed by discussing various methods of CNTs and graphene synthesis. Finally, a summary of current status and future prospects of green synthesis methods are discussed.