C2H2 Selective Hydrogenation over the M@Pd and M@Cu (M = Au, Ag, Cu, and Pd) Core–Shell Nanocluster Catalysts: The Effects of Composition and Nanocluster Size on Catalytic Activity and Selectivity
journal contributionposted on 10.06.2019, 00:00 by Riguang Zhang, Mifeng Xue, Baojun Wang, Lixia Ling, Maohong Fan
To clarify the effects of the composition and nanocluster size of the core–shell catalysts on C2H4 selectivity and activity in C2H2 selective hydrogenation, the kinetic mechanisms of C2H2 selective hydrogenation over different compositions of M@Pd (M = Au, Ag, and Cu) and M@Cu (M = Au, Ag, and Pd) nanoclusters with different sizes are investigated using density functional theory calculations. The results suggest that the composition and nanocluster size of the core–shell catalyst affect C2H4 selectivity and activity, and Cu as the core for M@Pd catalysts exhibits excellent C2H4 selectivity and activity than that of Au and Ag; moreover, M@Pd catalysts show better C2H4 selectivity and activity than M@Cu. Namely, the core–shell nanocluster catalyst with Cu as the core and Pd as the shell is beneficial to improve C2H4 selectivity and activity in C2H2 selective hydrogenation. On the other hand, C2H4 selectivity and activity increase over M@Pd catalysts with the increase in the nanocluster size, which means that it is necessary to have the catalyst with a larger cluster size in the preparation of Cu@Pd core–shell catalysts. The electronic structure analysis revealed the microscopic reasons about the effects of core–shell catalyst compositions and nanocluster size on the catalytic performance of C2H2 selective hydrogenation. This study can provide theoretical guidance for the design of core–shell nanocluster catalysts to improve C2H4 selectivity and activity in C2H2 selective hydrogenation by adjusting the composition and nanocluster size in an efficient way.