Introduction

Carbon-based nanomaterials (CBNMs), including graphene, carbon nanotubes, carbon spheres, carbon fibres and graphitic carbon nitride, are emerging as research hotspots owing to their distinct optical, electrical,structural and chemical properties. With the advancement in the material synthesis route, they can be functionalized and used in various environmental applications. Many CBNMs could be derived from renewable sources, providing viable and environmental friendly substitutes for conventional materials. Furthermore, they possessed large surface area, high charge transfer efficacy, low recombination rate and high stability. This chapter discusses a brief history of CBNMs, classification, and potential properties of carbon materials with different structures. The properties and structures of the graphene family, including graphene nanoribbons, graphene quantum dots, and graphene oxide, are briefly discussed. Moreover, the structural properties of carbon nanotubes (single-walled and multi-walled), carbon fibres with different precursors, carbon spheres (hollow and porous carbon spheres), and graphitic carbon nitride were addressed.