Front propagation at low temperatures and multiscale modeling for the catalytic combustion of H2 on Pt

A skeleton elementary reaction mechanism is employed in a molecular model (kinetic Monte Carlo simulation) and tested against spatially resolved scanning tunneling microscopy data for the first time during wave propagation in the catalytic combustion of H2 on a Pt surface at low temperatures. It is shown that while the predicted wave propagation is in qualitative agreement with experimental observations, this mechanism cannot predict quantitatively patterns on catalytic surfaces at low temperatures. Multiscale, hybrid (stochastic coupled with deterministic) simulations for the Pt combustion of H2 in a CSTR are then carried out using complex surface chemistry of 13 elementary reactions. It is found that while a continuum model based on a mean field description of the surface is adequate to predict ignition, large discrepancies from the multiscale predictions are observed on the ignited branch and for the extinction temperature due to adjacency requirements at the microscopic level.