Fan Wei - Graphene-Carbon Nanotube Hybrids for Energy and Environmental Applications

The Author(s) 2017

Wei Fan 1

Abstract

Carbon-based materials ranging from activated carbons, carbon nanotubes (CNTs) to graphene have attracted tremendous attention because of their diversified nanostructures, excellent physical and chemical properties. These properties include variety of forms (powders, fibers, aerogels, composites, sheets, monoliths, tubes, etc.), relatively inert electrochemistry, ease of processability, and controllable porosity. Graphene and CNTs, both comprised of sp2 hybridized carbon atoms, possess unique electrical, mechanical, thermal, catalytic, and electrochemical properties, which have dominated the entire field of material sciences. Graphene, with a two-dimensional layered structure, is the thinnest known material in the universe to date. When infinite graphene crystals become finite and boundaries appear, forming non-three coordinated atoms at the edges, one-dimensional graphene nanoribbons (GNRs) are born and exhibit different properties from that of graphene. GNRs can open a band gap in graphene due to the electron confinement and the presence of edge states, making them attractive as building blocks for basic electronic devices such as transparent electrodes, field effect transistors, and nanoelectromechanical switches.

Keywords

Carbon is a unique, fascinating and very versatile element which is capable of forming different architectures at nanoscale, possessing different physical and chemical properties. Over the past 30 years, new members of the carbon nanostructure family arose, and more are coming. The discovery of C60 Buckminsterfullerene, a beautiful cage-like carbon molecule of 7 in diameter, stimulated the creativity and imagination of scientists and paved the way to a whole new chemistry and physics of nanocarbons []. The unique properties of this 2D atomic crystal have greatly stimulated an extensive study of graphene. New carbon structures with sp2 hybridization, such as bilayer and few-layer graphene, graphene, and graphitic nanoribbons have subsequently emerged, each with novel and unique properties.