First principles analysis of graphene and its ability to maintain long-ranged interaction with H2S

Vinay I. Hegde, Sharmila N. Shirodkar, Nacir Tit, Umesh V. Waghmare, Zain H. Yamani

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

We determine the chemical activity of (a) carbon site of pristine graphene, (b) Stone-Wales (SW) defect site, and (c) BN-sites of BN-doped graphene towards adsorption of a toxic gas H2S, through comparative analysis based on first-principles density functional theoretical calculations incorporating van der Waals (vdW) interactions. While the adsorption of H2S is weak at both C and BN sites with a binding energy of 15 k J/mol, it is significantly stronger at the Stone-Wales defect site with a much higher binding energy of 26 k J/mol. This is clearly reflected in the contrasting orientation of H 2S molecule in the relaxed geometries: the sulfur atom of H 2S is closer to graphene (at a distance 3.14 Å) during physisorption at C and BN sites, while the molecule's H atoms come closer to graphene (at a distance 2.84 Å) during physisorption at the Stone-Wales defect site. The origin of the stronger binding interaction between H 2S and a SW defect site is attributed to two possible reasons: (i) an increase in the vdW interaction; and (ii) the lowering of both energy of the HOMO level and the total energy of the H2S molecule in attaining a stable configuration. Our findings are compared to the available theoretical results and their technological relevance is further discussed.

Original languageEnglish
Pages (from-to)168-174
Number of pages7
JournalSurface Science
Volume621
DOIs
Publication statusPublished - Mar 2014

Keywords

  • Adsorption kinetics
  • Desorption kinetics
  • Electronic structure of graphene
  • Impurity and defect levels

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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