Atomic Imaging of Oxide-Supported Metallic Nanocrystals

作者：Feng Zhenxing; Kazimirov Alexander; Bedzyk Michael J^*

来源：ACS Nano, 2011, 5(12): 9755-9760.

DOI：10.1021/nn203273e

• nanoparticles
• epitaxy
• atomic imaging
• interface structure
• X-ray standing waves
• platinum
• strontium titanate

The nucleation of noble metal nanoparticles on oxide surfaces can lead to dramatic enhancements in catalytic activity that are related to the atomic-scale formation of the nanoparticles and interfaces. For the case of submonolayer Pt deposited on the 2x1 SrTiO(3)(001) surface atomic-force microscopy shows the formation of nanoparticles. We use X-ray standing wave (XSW) atomic imaging to show that these nanoparticles are composed of Pt face-centered-cubic nanocrystals with cube-on-cube epitaxy laterally correlated to the substrate unit cell. The phase sensitivity of the XSW allows for a direct measurement of the Interface offset between the two unit cells along the c-axis. Different Pt coverages lead to differences In the observed XSW Image of the Interfacial structure, which Is explained by a proposed model based on the Pt-Pt interaction becoming stronger than the Pt-substrate Interaction as the global coverage is Increased from 0.2 to 0.6 ML.

• 出版日期2011-12
• 单位西北大学