Structure and Reactivity
We study surface chemistry of oxide-supported metal and transition metal oxide nanoparticles focusing on effects of particle size, shape and the nature of oxide support on reactivity, particularly in the CO2 hydrogenation reactions.
The mono- and multi-component particles, prepared by inverse micelle encapsulation technique, are deposited onto planar oxide supports by dip coating followed by the oxygen plasma and calcination-reduction treatments. In addition, the metallic particles can be prepared by physical vapor deposition in vacuum.
In several UHV setups, we use a variety of “surface science” techniques such as scanning probe microscopy (SPM), Auger electron spectroscopy (AES), temperature programmed desorption (TPD), infrared reflection absorption spectroscopy (IRAS) (also in polarization-modulation mode, PM-IRAS), and X-ray photoelectron spectroscopy (XPS) in UHV as well as at near atmospheric pressures (NAP-XPS). In addition, the elementary steps of reactions are addressed by molecular beam (MB) studies in combination with IRAS. The catalytic activity of model planar catalysts under both UHV-compatible and realistic conditions can be monitored by a gas chromatography and mass-spectrometry.
The results on model catalysts are compared to the “real” systems prepared on high surface area supports to rationalize the structure-reactivity relationships.