Van Marum Colloquium: Making Kinetics at Surfaces a More Exact Science
- Tuesday 15 November 2022
2333 CC Leiden
Quantitative understanding of reactions at surfaces is essential for rational design of catalytic materials for large-scale chemical transformations. The quality of a catalyst is typically evaluated by the degree it enhances the product formation rate, its selectivity for the particular product and its resistance against processes leading to its deactivation. All these properties can be fully characterized when elementary rate constants of all underlying processes, like adsorption, diffusion, reaction and desorption are determined from experiment or theory. Today catalyst discovery is transitioning more and more into full in silico modelling. Unfortunately, many methods employed in this context remain without validation from precise experiments. Given the fact that these untested methods are likely to influence our choice of the catalytic material for a given purpose, this situation remains highly unsatisfying.
During the last few years we established the Velocity Resolved Kinetics (VRK) technique, which opened up the possibility to study transient surface reaction rates with extraordinary precision. We focused on characterization of elementary rate constants for desorption, site-to-site hopping and active-site specific reactions on atomically stepped and flat single crystal surfaces. In the first part of my talk, I want to review some of our most important findings with special focus on benchmarking methods for thermal rate and rate constant modelling. In the second part of my talk, on the example of NH3 oxidation on Pt, I want to discuss strategies for characterization of elementary rate constant even for rather complicated surface reaction mechanisms. I will conclude with a few examples on how to bridge the gap between laboratory and real world heterogeneous catalysis applications.