Investigation of Graphene as an absorbent for some gases: A DFT Study

DFT studies could provide insights on the interactions between different gas molecules andgraphene sheet. Thereby, elucidating the role of various graphene sheets on the catalyst activitytoward gas molecules selective adsorption[1-3]. At the present theoretical study, DFT calculationswere performed for elucidating the reaction, absorption energy and the quantum moleculardescriptors including electronic chemical potential(μ), chemical hardness(ɳ), Homo, Lumo, bandgap energy (Eg)[4] and finding the most active graphene sheet for absorption H2S, CH4, N2 andCO2 gases. We want to predict interaction between graphene and some gases have been studiedwith DFT using B3LYP method and 6-31G basis set. According to our DFT analysis, the higher activity of H2S toward graphene selectiveabsorption can be attributed to this capability in H2S dissociation. Also, based on the obtainedquantum molecular descriptors, the proposed graphene sheet shows a good selectivity forabsorption gases. From Eg calculations, it can be seen that Eg are decreased in the order:graphene to H2S > graphene to CH4> graphene to N2> graphene to CO2. Decrease of Eg promisemore stable compound. So, Graphene beside the CO2 can act as a better electron donor to higherelectrical conductivity. Chemical hardness and chemical potential of all the samples except thegraphene sheet to H2S are in the same range. However, graphene sheet to H2S possesses the mostchemical hardness and chemical potential indicating that graphene sheet interaction with H2S isharder than the others. Finally it is predicted that the graphene sheet was determined as the mostactive phases toward H2S adsorption.

Keywords:

DFT , Graphene , Some gases , Different Properties