O'Connor Christopher R, van Spronsen Matthijs A, Egle Tobias, Xu Fang, Kersell Heath R, Oliver-Meseguer Judit, Karatok Mustafa, Salmeron Miquel, Madix Robert J, Friend Cynthia M
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA.
Nat Commun. 2020 Apr 15;11(1):1844. doi: 10.1038/s41467-020-15536-x.
Heterogeneous catalysts are complex materials with multiple interfaces. A critical proposition in exploiting bifunctionality in alloy catalysts is to achieve surface migration across interfaces separating functionally dissimilar regions. Herein, we demonstrate the enhancement of more than 10 in the rate of molecular hydrogen reduction of a silver surface oxide in the presence of palladium oxide compared to pure silver oxide resulting from the transfer of atomic hydrogen from palladium oxide islands onto the surrounding surface formed from oxidation of a palladium-silver alloy. The palladium-silver interface also dynamically restructures during reduction, resulting in silver-palladium intermixing. This study clearly demonstrates the migration of reaction intermediates and catalyst material across surface interfacial boundaries in alloys with a significant effect on surface reactivity, having broad implications for the catalytic function of bimetallic materials.
多相催化剂是具有多个界面的复杂材料。在合金催化剂中利用双功能的一个关键命题是实现跨越分隔功能不同区域的界面的表面迁移。在此，我们证明，与纯氧化银相比，在氧化钯存在的情况下，银表面氧化物的分子氢还原速率提高了10倍以上，这是由于原子氢从氧化钯岛转移到由钯银合金氧化形成的周围表面所致。钯银界面在还原过程中也会动态重构，导致银钯混合。这项研究清楚地证明了反应中间体和催化剂材料在合金表面界面边界的迁移对表面反应性有显著影响，这对双金属材料的催化功能具有广泛的意义。
