Adsorption of a Pt₁₃ cluster on graphene oxides at varied ratios of oxygen to carbon and its catalytic reactions for CO removal investigated with quantum-chemical calculations

We applied periodic density-functional theory to investigate the interaction of a Pt₁₃ cluster on graphene oxide (GO) sheets at varied ratios of oxygen to carbon and on a pristine graphene sheet. Relative to a pristine graphene sheet, the existence of oxygen atoms in an appropriate proportion in the formation of graphene oxide enhanced the adsorption capability of a Pt₁₃ cluster. The O/C ratio of GO sheets had the following influences on the Pt₁₃ cluster adsorption behavior: (i) for O/C ratio < 0.125, the Pt₁₃ cluster abstracted the neighboring oxygen atom from a GO sheet to form Pt₁₃O, or aggregated with an adjacent cluster to form a larger cluster; (ii) for O/C ratio ≥ 0.125, the Pt₁₃ cluster was stabilized and dispersed on the GO sheet. We calculated also the adsorption behavior of carbon monoxide on a Pt₁₃/GO sheet; a strong interaction between the Pt₁₃ cluster and the GO sheet modulated the electronic structure of the Pt₁₃ cluster, thus decreasing the CO adsorption energy, which in turn decreased the combined barriers, CO + O and CO + OH, in the watergas shift reaction (WGSR) and improved the CO tolerance of the Pt catalyst. (Graph Presented).