Kinetics and Mass Transport in Plasma Catalysis*

Coupling non-equilibrium plasma with heterogeneous catalysis offers a sustainable electrically driven route to produce a broad range of chemicals. Plasma catalysis leverages the highly selective nature of catalytic processes on surfaces and the activation of strong chemical bonds in, for example N₂, by non-equilibrium electron-induced plasma reactions. In this presentation, we will report our work that probed mechanisms of coupling plasma- and catalytic-chemistry in plasma afterglows. The well-defined hydrodynamics in short contact time reactors equipped with a molecular beam mass spectrometry enabled us to determine the rates of plasma-driven and catalytic surface chemistry. These studies establish a quantitative description of plasma-catalyst interactions and elucidated selective routes for converting N₂ in plasma-catalytic reactors. A key outcome of the work is the exceedingly important role of mass transport, of which we will highlight a few examples. The research provides critical insights for improving plasma catalytic reactor design which in the last decade has often been based on empirical reactor optimization.