H2S adsorption and dissociation on NH-decorated graphene: A first principles study

• Published in: Surface science 2018-02, Vol.668, p.100-106
• Main Authors: Faye, Omar, Eduok, Ubong, Szpunar, Jerzy, Samoura, Almoustapha, Beye, Aboubaker
• Format: Article
• Language: English
• Subjects: Density functional theory; Dissociation; Graphene composite; H2S adsorption
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2017.10.016

•Adsorption and dissociation of H2S molecule on NH-doped graphene were studied.•We predicted that the adsorption of H2S was enhanced by the nitene radicals (NH).•We showed that there is partial dissociation at a weight percent of 3.76 wt% of NH radical.•We also observed a complete dissociation of H2S molecule at 7.25 wt% NH radical.•The H-transfer of the second H atom of H2S molecule at 3.76 wt% was energetic unfavorable. The removal of H2S gas poses an emerging environmental concern because of the lack of knowledge of an efficient adsorbent. A detailed theoretical study of H2S adsorption and dissociation on NH-doped graphene (GNH) has been carried out by means of density theory calculations. Our results reveal that the adsorption of H2S molecule on GNH composite is enhanced by the presence of active site such as the NH radicals. These NH radical sites formed NHH bonds and increase the charge transfer from H2S to GNH. The dissociation of the adsorbed H2S molecule leads the chemisorption of SH radical via H-transfer to GNH, while the formation of GNH2 at a weight percent of 3.76 wt% of NH radical is an endothermic process with an energy of 0.299 eV and 0.358 eV for ortho and para-position respectively. However, at 7.25 wt% NH radical, we observed a complete dissociation of H2S molecule with an energy released of 0.711 eV for the chemisorbed S atom on GN2H4. Moreover, the H-transfer of the second H atom of H2S molecule at 3.76 wt% was energetic unfavorable. The trend of predicted results within this study reveals that NH-doped graphene (GNH) successfully adsorbed and eliminated of H2S molecule; this work unveils definitive theoretical procedures which can be tested and validated experimentally. [Display omitted]