Platinum-doped graphene: The next generation gas sensing

Carbon-based nanostructures functionalized by transition metals have attracted attention as efficient sensors and storage mediums of various gases. In this project, we use density functional theory (DFT) to investigate sensing and storage capacity of H₂, S₂, and CH₄ gases on Pt-doped graphene. We establish a hierarchy of models of Pt chemisorption to graphene, including single Pt atoms, Pt₁₃, and Pt₅₅ atomic clusters. For the Pt clusters, we adopt the cuboctahedron geometry with its triangular side facing graphene, which is found to be energetically favorable compared to the icosahedron geometries. To investigate the sensibility at different levels of H_2, S₂, and CH₄ adsorption, we examine the changes in electronic transport properties upon the gradual adsorption of gas molecules to the energetically favorable sites around Pt, which are identified by using a combined strategy of ab initio random search and molecular dynamics (MD). We find that gas adsorption alters the resistivity of Pt-doped graphene based on the gas type and the number of adsorbed gas molecules. These results indicate that Pt-doped graphene can be utilized for the next-generation gas sensors.