Measuring reaction rates for heterogeneous catalysis

Heterogeneous catalysis on solid surfaces provides high-value chemicals and is involved in a large fraction of the world’s economic productivity, yet our understanding of this important class of processes remains limited. Thermal reaction rates obtained from experiments on model catalysts provide quantitative data that can reveal reaction mechanisms and provide benchmarks for computational simulations of catalytic processes. This perspective describes a critical advance in measuring these rates: velocity resolved kinetics (VRK). VRK delivers absolute rates for elementary surface reactions that are of sufficient accuracy that they may be meaningfully compared to theoretical rate predictions, creating a powerful synergy between theory and experiment. It is now routinely possible to derive fundamental thermochemical quantities, including desorption and adsorption energies, reaction barrier heights, diffusion barrier heights, and lateral adsorbate interaction energies. Reaction mechanisms can also be revealed and reaction intermediates directly detected. The high time resolution of VRK allows study of catalytic reactions at the high temperatures typical of conditions present in real catalytic reactors. Current work exploiting the newest and by far the most powerful variant of VRK has only scratched the surface of what is possible, signifying a promising future for researchers in this field.