On the Catalytic Activity of Pt Supported by Graphyne in the Oxidation of Ethanol.

The adsorption of Pt clusters on β- and γ-graphyne (β-GY, γ-GY), graphdiyne (GDY), and graphene (GP) was extensively investigated with density functional theory. Ethanol adsorption and its partial oxidation on the Pt supported by the GY and GP were then explored to address the influence of the supporting materials on the activity of Pt nanoclusters to ethanol oxidation. Among the examined adsorption sites such as the hollow, Csp-Csp, and Csp-Csp2 bonds, the hollow site consisting of multiple triple bonds is the most attractive one to adsorb Pt and Pt4 regardless of β-GY, γ-GY, and GDY. The binding of Pt4 to the GDY is slightly stronger than those of β-GY and γ-GY (binding energy: -3.64, -3.73, and -4.08eV). It is remarkable that the adsorption of Pt4 on GY is 2-3 times stronger than that on GP (-3.6-4.1 vs -1.3 eV), showing that the GY and GDY are better substracts than the GP for the stability of Pt clusters. Furthermore, the potential energy profiles for the oxidation of ethanol show that in spite of the higher energy barrier for the adsorbed ethanol on Pt4 supported by γ-GY than by GP (1.54 vs 1.19eV), the dehydrogenation product and of ethanol on Pt-graphyne is much stabler than that on Pt-graphene, suggesting that graphyne is thermodynamically more favorable than graphene as a subtract for the Pt catalyst.