Kinetics and Dynamics at Surfaces

ended

This proposal implements slice imaging to measure catalytic rates for site-specific elementary reactions thus offering remarkable opportunities to advance our fundamental understanding of heterogeneous catalysis. As evidence for global climate change continues to grow, catalysis has moved to the front line of the struggle to obtain new, sustainable technologies for the future. Catalysis and catalytic processes account, directly or indirectly, for 20-30 % of world Gross Domestic Product. Knowledge of elementary chemical reaction mechanisms in heterogeneous catalysis underlies our ability to construct comprehensive kinetic models for many such important chemical processes, in order to optimise them. Our proposed strategy makes the formidable task of describing site-specific chemical reaction mechanisms and elementary rates in heterogeneous catalysis facile, while its necessity we justified (Nature 2018) on the prototypical CO oxidation reaction on Pt by demonstrating that 40 years of traditional experimentation led to false interpretation of the reaction mechanism. The aim of this proposal is characterize the important factors that influence the kinetics of elementary reactions at surfaces, e.g. the chemical nature of the catalyst and the geometry of the active site (stereodynamics). We chose elementary reactions involving C, H, O, N, as these are important in many key industries, such as the methane reforming, syngas, fuel cells, Fischer-Tropsch synthesis and the Haber-Bosch process. Our strategy is that of a “bottoms up” approach to catalysis, i.e., building and understanding complex heterogeneous chemical catalysis, from the site-specific kinetics of the elementary building block reactions. Our measurements, will serve for benchmarking first principles calculations of reaction rates in surface chemistry. Our methodology measures the kinetics in the s regime with temperatures in the 200 to 1000 K range, i.e, more relevant to industrial conditions.