A comparative DFT study of the adsorption of hydrogen on Li-doped defective (8,0) SWCNT and on graphene

C.R. LUNA; G. BRIZUELA; A. JUAN; M. PATRIGNANI; C. PISTONESI; P. BECHTHOLD; P. JASEN

La Plata

Workshop; VIII Workshop on Novel Methods for Electronic Structure Calculations Introduction to Computational Modeling Methods in Materials Science; 2019

CONICET-UNLP

This work presents a theoretical study, based on DFT calculations, about the changes induced when diatomic molecules (CO, O2 and H2) are adsorbed on defective (8,0) SWCNT doped with a Li atom and a comparison with defective graphene. The adsorption of one Lithium atom is tested inside and outside of the nanotube containing a single vacancy. The Li atom induces a magnetic moment onthe nanotube and an important reduction in its the band gap (Eg). The adsorption energy values (Eads) for CO, O2 and H2 when Li is located inside, are higher than when Li is outside. The H2 adsorption does not change the magnetic nature of the system. However, the CO and O2 molecules reduce the magnetic moment from 1.0 B to 0.0 B. The band gap energy is reduced for CO and O2, while increases in the case of H adsorption. The work function (WF) value is reduced in the cases of CO and H2; whereas for O2 we observed an opposite behavior, then the nal charge state of this molecule is negative. Based on our results, the system Li+defective (8,0) SWCNT can be proposed as possible candidate as gas sensor of CO, O2 and H2. In the case of graphene with vacancies the adsorption is also stronger at the vacancy. The eect of B or N substitution is also discussed.