In this paper, we will describe the experimental processes involved in analytical atomic-resolution scanning transmission electron microscopy (STEM) of supported nano-scale systems. We show that the combination of high-resolution Z-contrast imaging and electron energy loss spectroscopy (EELS) provides an analytical tool with unprecedented chemical and spatial sensitivity that is vital for studying interfaces in heterogeneous catalyst systems. We apply the described methods to study two example heterogeneous catalyst systems: Pt/SiO2, and Cu/Al2O3. In particular, the presence of a few monolayers of platinum oxide in Pt/SiO2 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. The Cu/Al2O3, reduced at various temperatures, exhibits an increasing oxidation of the Cu-particles upon higher temperature reduction.
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