CBE Shell Seminar Series – Randall Meyer

Descriptor Search for Metal Oxide Reactivity and Transport

Dr. Randall J. Meyer obtained his PhD degree in Chemical Engineering at the University of Texas at Austin. He has authored over 90 publications and 5 patents in which he has used a variety of techniques to study heterogeneous catalysis focusing mostly on a combination of density functional theory, kinetic modeling and X-ray absorption spectroscopy.

Abstract: Metal oxides play a prominent role in enabling many important technologies such as heterogeneous oxidation catalysis, oxygen transport membranes, solid oxide fuels and oxygen storage materials.  In the Inorganic Crystal Structure database nearly 40,000 pristine oxide structures have been recorded. However, when dopants to the crystal lattice are considered, the number of different synthesizable metal oxide materials grows even further.  Descriptors for their reactivity and ion conductance that capture the effect of local structure are therefore highly desirable in order to focus researchers on the most appropriate set of materials for a given application.  Different classes of descriptors for oxygen ion transport have been identified which account for the geometric effects (e.g. void volume, transport window), electronic structure effects (e.g. M-O bond strength) and dynamic effects (e.g. phonon band center). Similar descriptors have previously been developed for reactivity of metal oxide surfaces. In this work, building upon the previous literature, we hope to develop multi-descriptor predictive relationships as no single descriptor can capture the complex chemistry of these materials. In addition, we attempt to build descriptors based on local structure as bulk material properties may not be reflective of the atomistic level events described here in transport and catalysis. Although we focus here primarily on oxygen ion transport, some implications and approaches for the more complicated problem of surface reactivity will be presented.