The Adsorption of hydrogen on Li-Doped Defective (8,0) SWCNT: a DFT Study

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

Pisa

Conferencia; ICASS 2019 3rd International Conference on Applied Surface Science; 2019

Elsevier

This work presents a theoretical study, based onDFT calculations, about the changes induced when diatomic hydrogen moleculesare adsorbed on defective (8,0)SWCNT doped with a Li atom. First principlescalculations are implemented through the Vienna Ab initio Simulation Package(VASP) code. We used GGA approximation (GGA) and PBE functional with aplane-wave basis set, implementing the PAW. We have included the use of theDFT-D2 Grimme method. We computed the adsorption energies, magnetic moment,density of states (DOS) curves, Bader charges and electrostatic potentials. Theadsorption of one Lithium atom is tested inside and outside of the nanotubecontaining a single vacancy. The Li atom induces a magnetic moment on thenanotube and an important reduction in its the band gap (Eg). The presence ofLithium induces a magnetic moment of 1.0 μB and a reduction ofband gap value from 0.48 eV to 0.09 eV and 0.24 eV for outer and inner Li,respectively. The Li atom acts as a donor of electrons, that is to say thedefective nanotube after adsorption is negatively charged. These facts make thesystem Li+(8,0) SWCNT a good candidate to be used as a negative electrode inLithium-ion batteries and to be used in spintronic area. The adsorption energyvalues (Eads) for H2 when Li is located inside, arehigher than when Li is outside. The H2 adsorption does not changethe magnetic nature of the system.  Theband gap energy is increased after hydrogen adsorption while the work function(WF) value is reduced. Based on our results, the system Li+defective (8,0)SWCNT can also be proposed as possible candidate as H2 sensor. Acomparison is provided with adsorption on defective graphene.<!-- /* Font Definitions */ @font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:10.0pt;mso-bidi-font-size:12.0pt;font-family:"Times New Roman",serif;mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-GB;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:10.0pt;mso-ansi-font-size:10.0pt;mso-bidi-font-size:10.0pt;}@page WordSection1{size:612.0pt 792.0pt;margin:72.0pt 72.0pt 72.0pt 72.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->