Single-atom catalyst (SAC) with the highest utilization of active sites is a new frontier in heterogeneous catalysis. SACs with a number of support types like metal oxides, pure metals, carbon materials, metal-organic frameworks, zeolites, etc., have been investigated experimentally and computationally. Among them, graphene has been identified as one of the most promising candidates for the next generation support of catalysts due to its unique electronic and geometric properties. Moreover, graphene supported SACs exhibit high catalytic activity for many redox and electro-catalytic reactions. Recently, graphene supported SACs are shown to exhibit remarkable hydrogenation selectivity experimentally. It is thus important to unveil the nature of hydrogenation selectivity and catalytic activation of this kind of SACs. In this work, we have performed periodic density functional theory (DFT) calculations to investigate the reaction mechanism of acetylene hydrogenation catalyzed by single/double vacancy graphene (SV/DV-G) supported single-atom Pt1 catalyst. It is shown that the interaction between single Pt1 atom and SV/DV-G support is stable enough to prevent the diffusion and aggregation of single atoms. The reactants, C2H2 and H2, can be simultaneously activated at the Pt1 atom. The energetically favored catalytic processes proceed via semi-hydrogenation of acetylene to ethylene, where hydrogenation of ethylene to ethane has a high-energy barrier. The computational results also suggest that Pt1/DV-G exhibits better selectivity than Pt1/SV-G for acetylene hydrogenation.

Selective hydrogenation of acetylene on graphene supported single-atom Pt catalyst

254th National Meeting (2017)

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