Reaction-Induced Cluster Ripening and Initial Size-Dependent Reaction Rates for CO Oxidation on Ptn/TiO2(110)-(1脳1)

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• 作者：Simon Bonanni ; Kamel A茂t-Mansour ; Wolfgang Harbich ; Harald Brune
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：June 18, 2014
• 年：2014
• 卷：136
• 期：24
• 页码：8702-8707
• 全文大小：431K
• 年卷期：v.136,no.24(June 18, 2014)
• ISSN：1520-5126

文摘

We determined the CO oxidation rates for size-selected Pt_n (n {3,7,10}) clusters deposited onto TiO₂(110). In addition, we investigated the cluster morphologies and their mean sizes before and after the reaction. While the clusters are fairly stable upon annealing in ultrahigh vacuum up to 600 K, increasing the temperature while adsorbing either one of the two reactants leads to ripening already from 430 K on. This coarsening is even more pronounced when both reactants are dosed simultaneously, i.e., running the CO oxidation reaction. Since the ripening depends on the size initially deposited, there is nevertheless a size effect; the catalytic activity decreases monotonically with increasing initial cluster size.