Hydrogen molecule adsorption and sensing on lanthanide (La) doped/decorated carbon nanotube and graphene structures

Abstract

The use of carbon nanotube (CNT) and graphene structures as doped and decorated with La atom as an adsorbent and a sensor material for hydrogen molecules was investigated by the density functional theory method. It is seen that the hydrogen interaction increased significantly after the La modification on the CNT and graphene. The fact that the adsorption enthalpy values are smaller than the liquefaction enthalpy value of hydrogen indicates that they can be used as adsorbent materials for hydrogen adsorption. While the adsorption energy values are better in the modification with La doping in the CNT structure, the results in the graphene structure are better in the decoration with the La atom. Charge transfer has occurred between the structures modified with La and the hydrogen molecule. After the hydrogen interaction, HOMO–LUMO gap values decreased in La-modified CNT structures and increased in graphene structures. This signifies that the La-modified CNT structures could be electronic sensors for hydrogen molecules. Consequently, the CNT and graphene structures doped and decorated with La can be used as adsorbents for hydrogen molecules. In addition, La-modified structures have electronic sensor properties.