Role of the nanoscale in catalytic CO oxidation by supported Au and Pt nanostructures

阅读量：

作者：

Sergey，N.，Rashkeev，Andrew，R.，Lupini，Steven，H.，Overbury，Stephen

展开

摘要：

Experiments have found that the catalytic activity of Au increases sharply for supported nanoparticles smaller than 5nm, while Pt exhibits the opposite behavior. Several authors, seeking to explain the nanoscale Au activity, reached conflicting conclusions, attributing it to different nanoscale features or to a particular bilayer structure that is independent of size. Here, we report an extensive theoretical study of a large ensemble of TiO2-supported Au and Pt nanoparticles and show that several nanoscale features collectively result in the observed contrasting behavior. Low coordination is accompanied by bond weakening in Au and strengthening in Pt, while perimeter sites are active only for Au. Though there are orbital-occupancy differences for catalytically active and inactive configurations, there is insignificant variation in physical-charge transfer. Finally, we report atomically resolved Z-contrast images that confirm bond weakening in catalytically active TiO2<

展开

关键词：

surface and interface chemistry heterogeneous catalysis at

DOI：

10.1103/physrevb.76.035438

被引量：

165

年份：

2007