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Size-Selected Cluster Deposition and Model Catalyst Studies

The problem:

Many important catalysts consist of small clusters or nanoparticles of active metals or metal oxides, dispersed on a high surface area support (e.g. titania, alumina, silica). These catalysts are complex and difficult to study, therefore many groups have turned to planar model catalysts where catalytic clusters/nanoparticles are grown on a single crystal or thin film support, allowing them to be studied by surface science methods like STM, ion scattering, electron spectroscopies, and a variety of mass spectrometry methods. In such experiments, there is still a rather broad range of cluster/nanoparticle sizes present, as well as distributions of metal-support geometries. In our experiments, we grow catalytic cluster ions in the gas phase, then use a mass spectrometer to select a particular size/composition of interest, which is then deposited on a single crystal support to make a truly monodisperse model catalyst. We then use a variety of in situ methods to characterize morphology, electronic structure, adsorbate binding, and catalytic activity. Typical results are summarized in the PDF files linked below.

Funding AFOSR and DOE

Recent Results: (Note: the slide shows may be too big if you have a slow internet connection).

CO oxidation on Aun on TiO2

Hydrazine on Irn on Al2O3

CO oxidation over Pd/TiO2 - correlations of activity with electronic structure and adsorbate binding

Last Updated: 6/3/21