Surface study of platinum decorated graphene towards adsorption of NH₃ and CH₄

To distinguish the potential of graphene sensors, there is a need to recognize the interaction between graphene sheet and adsorbing molecules. We used density functional theory (DFT) calculations to study the properties of pristine as well as Pt-decorated graphene sheet upon adsorption of NH₃ and CH₄ on its surface to exploit its potential to be as gas sensors for them. We found much higher adsorption, higher charge transfer, lower intermolecular distance, and higher orbital hybridizing upon adsorption of NH₃ and CH₄ gas molecules on Pt-decorated graphene compared to pristine graphene. Also our calculations reveal that the adsorption energies on Pt-decorated graphene sheet are in order of NH₃ >CH₄ which could be corresponded to the order of their sensitivity on this modified surface. We used orbital analysis including density of states as well as frontier molecular orbital study for all analyte-surface systems to more understanding the kind of interaction (physisorption or chemisorption). Consequently, the Pt-decorated graphene can transform the existence of NH₃ and CH₄ molecules into electrical signal and it may be potentially used as an ideal sensor for detection of NH₃ and CH₄ in ambient situation. - Highlights: • Pt-decorated graphene was investigated as an adsorbent for NH₃ and CH₄. • Much higher adsorption of NH₃ and CH₄ on Pt-decorated graphene than pristine graphene. • Higher adsorption of NH₃ compared to CH₄ on Pt-decorated graphene. • Pt influences the electronic structure of graphene.