Hydrogen Storage on Platinum-Decorated Carbon Nanotubes with Boron, Nitrogen Dopants or Sidewall Vacancies

TL;DR

This study uses first-principle calculations to explore how doping and vacancies in platinum-decorated carbon nanotubes affect hydrogen adsorption, revealing enhanced storage capacity with sidewall vacancies.

Contribution

It demonstrates that sidewall vacancies enable Pt-decorated CNTs to adsorb and desorb more hydrogen molecules under ambient conditions, improving hydrogen storage potential.

Findings

Sidewall vacancies increase hydrogen adsorption capacity.

Dopants do not reduce maximum hydrogen molecules adsorbed.

Enhanced hydrogen release with vacancies under ambient conditions.

Abstract

The interaction between hydrogen molecules and platinum (Pt)-decorated carbon nanotubes (CNTs) with boron (B)-, nitrogen (N)-dopants or sidewall vacancies is discussed from first-principle calculations. The adsorption patterns of hydrogen molecules on four types of Pt-decorated CNTs are investigated, and the partial density of states projected on the Pt atom is computed to reveal the response to the number of hydrogen molecules, dopants or vacancies. It is found that the B-, N-dopants or sidewall vacancies can adjust the binding energy between the hydrogen molecules and the Pt atom deposited on the defective CNT, while not reducing the maximum number of hydrogen molecules that are chemically adsorbed on the Pt atom. It is demonstrated that the binding energy of the first H2 and the Pt atom on the pristine CNT or the CNT with the B-, N-dopants is quite strong, so each Pt atom in these three cases can only release the second H2 under ambient conditions. However, when the Pt atom is deposited on the CNT with sidewall vacancies, it can adsorb and desorb two hydrogen molecules under ambient conditions.