Titanium-decorated carbon nanotubes: a potential high-capacity hydrogen storage medium

TL;DR

This study uses first-principles calculations to show that titanium-decorated carbon nanotubes can adsorb significant amounts of hydrogen with stability and reversibility, promising for hydrogen storage applications.

Contribution

It demonstrates that Ti-decorated SWNTs can adsorb up to 8 wt% hydrogen with dissociative and molecular adsorption modes, advancing hydrogen storage material design.

Findings

Single Ti atom binds four H₂ molecules

High Ti coverage enables 8 wt% hydrogen adsorption

System shows stable and reversible hydrogen adsorption upon heating

Abstract

We report a first-principles study, which demonstrates that a single Ti atom coated on a single-walled nanotube (SWNT) binds up to four hydrogen molecules. The first H$_2$ adsorption is dissociative with no energy barrier while other three adsorptions are molecular with significantly elongated H-H bonds. At high Ti coverage we show that a SWNT can strongly adsorb up to 8-wt% hydrogen. The system is quite stable and exhibits associative desorption upon heating, a requirement for reversible storage. These results advance our fundamental understanding of dissociative adsorption of hydrogen in nanostructures and suggest new routes to better storage and catalyst materials.