Octagraphene as a Versatile Carbon Atomic Sheet for Novel Nanotubes, Unconventional Fullerenes and Hydrogen Storage

TL;DR

This paper introduces octagraphene, a new carbon sheet with unique structure and properties, capable of forming novel nanotubes, fullerenes, and effectively storing hydrogen, with potential applications in nanotechnology.

Contribution

The study presents the first-principles analysis of octagraphene, revealing its structure, electronic properties, mechanical strength, and potential for hydrogen storage and nanostructure fabrication.

Findings

Octagraphene is a stable, semimetallic carbon sheet with mechanical properties comparable to graphene.

Novel nanotubes and fullerenes can be constructed from octagraphene.

Hydrogen storage capacity of Ti-absorbed octagraphene is approximately 7.76 wt%.

Abstract

We study a versatile structurally favorable periodic $sp^2$-bonded carbon atomic planar sheet with $C_{4v}$ symmetry by means of the first-principles calculations. This carbon allotrope is composed of carbon octagons and squares with two bond lengths and is thus dubbed as octagraphene. It is a semimetal with the Fermi surface consisting of one hole and one electron pocket, whose low-energy physics can be well described by a tight-binding model of $\pi$-electrons. Its Young's modulus, breaking strength and Poisson's ratio are obtained to be 306 $N/m$, 34.4 $N/m$ and 0.13, respectively, which are close to those of graphene. The novel sawtooth and armchair carbon nanotubes as well as unconventional fullerenes can also be constructed from octagraphene. It is found that the Ti-absorbed octagraphene can be allowed for hydrogen storage with capacity around 7.76 wt%.