Density functional theory calculations are performed for CO oxidation over Pd single atoms supported on alumina. Both doped and adsorbed Pd single atoms are considered as structural motifs of the highly-dispersed alumina-supported catalyst. Multiple catalytic cycles are considered on adsorbed Pd single atoms, including carbonate-mediated and self-promoted CO oxidation, while a Mars van Krevelen mechanism is assumed on doped Pd single atoms. Exact, first-principles microkinetic modeling is used to quantify the effect of reaction conditions and the rate-determining step(s) along with the most important reaction intermediates. Simulations provide information insights into the active site, the dominant mechanism, and the state of the catalyst. Contrary to the common belief, we clearly show that under kinetically relevant conditions, the state of the catalyst is not described by <i>ab initio</i> thermodynamics. The dominant catalytic cycle for CO oxidation on these active sites proceeds via a carbonate-mediated mechanism without Eley-Rideal steps.<br/> <br/>

Computational operando spectroscopy and kinetics for single atom catalysis

2019 Spring National Meeting

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