Theoretical study on the removal of adsorbed sulfur on Pt anchored graphene surfaces

The adsorption and dissociation reactions of hydrogen sulfide (H2S) on the Pt atom anchored graphene (Pt-graphene) surfaces were investigated by first-principles calculations. It is found that the atomic S has stronger interaction with the Pt atom, while the SH and H2S species are weakly bound on the Pt-graphene surfaces. The adsorption of S-based species can regulate the electronic structure and magnetic properties of Pt-graphene systems. Besides, the calculated results show that the formation of SH and H from the H2S (H2S -> SH + H) is rather easy and further the hydrogenation reaction generates the hydrogen molecular (H-2), as well as leaving the SH anchors on the Pt atom (SH + H + H -> SH + H-2). Moreover, the preadsorbed S atom with the presence of H atoms can be converted into other species (SH or H2S) and thus inhibit the sulfur deposition on the Pt-graphene surfaces, which is expected to prevent the sulfur poisoning on graphene-based anode materials and boost the efficiency of fuel cells. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.