Multiple Ti and Li doped carbon nanoring for hydrogen storage

Multiple Ti and Li atom doped carbon nanorings are considered for hydrogen storage using density functional theory for the first time. There are five six membered carbon rings bonded through C-C bond in a carbon nanoring. Formation energy values show that both, Li as well as Ti atom doped carbon nanoring, are thermodynamically stable structures. Cohesive energy values indicate that Li and Ti atom doped carbon nanoring structures are more stable than undoped carbon nanoring. No clustering of metal atoms occurs in metal doped carbon nanorings which usually reduces the hydrogen storage capacity of a mate-rial. Li atom doped carbon nanoring is not suitable for hydrogen storage even at very low temperature at 1 atm pressure as well as at high pressure at room temperature. Ti atom doped carbon nanoring is suitable for hydrogen storage below 225 K and 1 atm pressure as well as at high pressure at room temperature. H2 desorption temperature is found to be 113 and 450 K for Li and Ti atom doped carbon nanoring respectively. H2 molecules interact strongly with Ti atom doped carbon nanoring than Li atom doped carbon nanoring that results in higher H2 desorption temperature for the former than the latter.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Multiple Ti and Li atom doped carbon nanorings were studied for hydrogen storage using density functional theory. The results showed that both Ti and Li doped carbon nanorings were thermodynamically stable and more stable than undoped carbon nanorings. Metal clustering, which reduces hydrogen storage capacity, was not observed in the doped nanorings. The Ti doped carbon nanoring was found to be suitable for hydrogen storage at low temperatures and high pressures, while the Li doped carbon nanoring was not suitable. The hydrogen desorption temperatures for the Ti and Li doped nanorings were 450 K and 113 K respectively, indicating stronger interaction between H2 molecules and Ti doped carbon nanoring.