Titanium-capped carbon chains as promising new hydrogen storage media

TL;DR

This study uses first-principles calculations to show that Ti-capped carbon chains can adsorb multiple hydrogen molecules, offering a promising approach for high-capacity hydrogen storage in one-dimensional carbon nanostructures.

Contribution

It demonstrates the potential of Ti-capped carbon chains as efficient hydrogen storage media with specific adsorption capacities depending on chain type.

Findings

Ti atoms strongly attach to carbon chains via d-p hybridization.

Each Ti atom can adsorb up to five or six H2 molecules depending on chain type.

Hydrogen storage capacity is optimized when TiC5 chains are terminated on C20 fullerenes.

Abstract

The capacity of Ti-capped sp carbon atomic chains for use as hydrogen storage media is studied using first-principles density functional theory. The Ti atom is strongly attached at one end of the carbon chains via d-p hybridization, forming stable TiCn complexes. We demonstrate that the number of adsorbed H2 on Ti through Kubas interaction depends upon the chain types. For polyyne (n even) or cumulene (n odd) structures, each Ti atom can hold up to five or six H2 molecules, respectively. Furthermore, the TiC5 chain effectively terminated on a C20 fullerene can store hydrogen with optimal binding of 0.52 eV/H2. Our results reveal a possible way to explore high-capacity hydrogen storage materials in truly one-dimensional carbon structures.