Speaker
Description
From simple molecular feedstocks, energy-dense and processable chemicals can be synthesized over heterogeneous catalysts. From a surface chemical physics perspective, these reactions can be modelled as a series of elementary reaction steps funneled through a potential energy landscape. A mechanistic understanding of these processes is of essence, as it enables tuning of the catalyst's activity and selectivity. To to gain this knowledge, we require techniques that (1) are surface sensitive, (2) provide high chemical specificity, and (3) are compatible with operating conditions. While X-ray photoelectron spectroscopy (XPS) has traditionally fulfilled the first two criteria, it has been largely limited to near-vacuum environments. We have developed instrumentation that helps close this “pressure gap,” enabling studies at more realistic conditions than previously possible.
This talk presents key insights enabled by these advances. By observing the adsorbate populations present under steady-state reaction conditions, we can directly compare experiments with predictive theoretical models of catalytic selectivity. This approach is particularly powerful for systems where the catalyst undergoes reaction-induced chemical changes, which are difficult to capture in silico. We demonstrate the influence of various promoters in ammonia synthesis, how different carbide species both enable - and partake in - the Fischer–Tropsch reaction, and how the state of bimetallic methanol synthesis catalysts evolves with reactant composition. Lastly, we provide an outlook for how continued development of instrumentation can increase the industrial relevance of fundamental catalysis research, and ultimately make the chemical industry both more sustainable and effective.