Adsorption of H₂S at Stone–Wales defects of graphene-like BC₃: a computational study

Abstract

We employed density functional theory to characterise H₂S adsorption, and dissociation on the pristine and Stone–Wales (SW) defected BC₃ graphenes. H₂S is predicted to be weakly adsorbed on the pristine graphene with the adsorption energy of about 7.11 kcal/mol. Two types of SW defects were generated by rotating a C–C bond (SW-CC) or a B–C bond (SW-BC) by about 90°. We predict that, in contrast to SW-BC, dehydrogenation of H₂S is energetically more favourable on the SW-CC compared to the associative adsorption. It is also found that SW-CC formation is more favourable than the formation of SW-BC. Molecular adsorption of H₂S on both of the SW defected sheets is more favourable than that on the pristine sheet. The preferable adsorption process on the SW-BC and SW-CC defected graphene sheets is via associative and dissociative mechanisms, respectively. Furthermore, the highest occupied molecular orbital and lowest unoccupied molecular orbital energy gap of the SW-BC defected sheet is highly sensitive to the adsorption process which may be used for the detection of H₂S.

Keywords:

• BC₃ graphene
• DFT
• nanostructures