Truttmann Vera, Drexler Hedda, Stöger-Pollach Michael, Kawawaki Tokuhisa, Negishi Yuichi, Barrabés Noelia, Rupprechter Günther
Institute of Materials Chemistry TU Wien Getreidemarkt 9/165 1060 Vienna Austria.
University Service Center for Transmission Electron Microscopy (USTEM) TU Wien Wiedner Hauptstraße 8-10 1040 Vienna Austria.
ChemCatChem. 2022 Jul 21;14(14):e202200322. doi: 10.1002/cctc.202200322. Epub 2022 May 18.
Monolayer protected Au nanocluster catalysts are known to undergo structural changes during catalytic reactions, including dissociation and migration of ligands onto the support, which strongly affects their activity and stability. To better understand how the nature of ligands influences the catalytic activity of such catalysts, three types of ceria supported Au nanoclusters with different kinds of ligands (thiolates, phosphines and a mixture thereof) have been studied, employing CO oxidation as model reaction. The thiolate-protected Au/CeO showed significantly higher CO conversion after activation at 250 °C than the cluster catalysts possessing phosphine ligands. Temperature programmed oxidation and infrared spectroscopy revealed that while the phosphine ligands seemed to decompose and free Au surface was exposed, temperatures higher than 250 °C are required to efficiently remove them from the whole catalyst system. Moreover, the presence of residues on the support seemed to have much greater influence on the reactivity than the gold particle size.
已知单层保护的金纳米团簇催化剂在催化反应过程中会发生结构变化，包括配体在载体上的解离和迁移，这会强烈影响其活性和稳定性。为了更好地理解配体的性质如何影响此类催化剂的催化活性，采用一氧化碳氧化作为模型反应，研究了三种负载在氧化铈上的、带有不同类型配体（硫醇盐、膦以及它们的混合物）的金纳米团簇。硫醇盐保护的Au/CeO在250℃活化后显示出比具有膦配体的团簇催化剂更高的一氧化碳转化率。程序升温氧化和红外光谱表明，虽然膦配体似乎会分解并暴露出金的表面，但需要高于250℃的温度才能有效地将它们从整个催化剂体系中去除。此外，载体上残留物质的存在对反应活性的影响似乎比金颗粒的尺寸更大。
