Atomic scale observations of the chemistry at the metal-oxide interface in heterogeneous catalysts
Atomic scale observations of the chemistry at the metal-oxide interface in heterogeneous catalysts
复制标题
非均相催化剂金属-氧化物界面化学的原子尺度观察
DOI：
10.1006/jcat.2001.3430
复制
发表时间：
2002
影响因子：
7.3
通讯作者：
N. Browning
中科院分区：
文献类型：
--
作者：
R. Klie;M. Disko;N. Browning
在这里，我们提出了一个初步的分析模型非均相催化剂系统，Pt/SiO2的原子尺度的界面化学。我们表明，Z-衬度成像和电子能量损失谱（EELS）在扫描透射电子显微镜（STEM）的组合表现出表面氧化和界面化学的变化，是高于传统的分析方法，如能量色散X射线光谱（EDS），化学吸附，和X射线吸收近边结构分析（XANES）的敏感性。特别地，可以清楚地看到存在几个氧化铂单层，并且可以将SiO2载体在金属-氧化物界面的0.1nm内的化学变化表征为催化剂制备条件的函数。这些结果表明，这种新技术的组合可以提供无与伦比的信息，这些信息可能是理解非均相催化剂体系的活性和选择性的关键。
Here we present a preliminary analysis of the atomic scale interface chemistry in a model heterogeneous catalyst system, Pt/SiO2. We show that the combination of Z-contrast imaging and electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) exhibits a sensitivity to surface oxidation and changes in the interfacial chemistry that is higher than that of conventional analytical methods such as energy-dispersive X-ray spectroscopy (EDS), chemisorption, and X-ray absorption near edge structure analysis (XANES). In particular, the presence of a few monolayers of platinum oxide can be clearly seen, and changes in the chemistry of the SiO2 support within ∼1 nm of the metal–oxide interface can be characterized as a function of the catalyst preparation conditions. These results demonstrate that this combination of novel techniques can provide unparalleled information that is potentially the key to understanding the activity and selectivity of heterogeneous catalyst systems.