Bronsted-Evans-Polanyi relation for CO oxidation on metal oxides following the Mars-van Krevelen mechanism

Scaling relations are widely used to model catalytic reactions on metal surfaces, but they are less commonly applied to metal oxides. Oxygen vacancy formation energies have been suggested as a descriptor for the activity toward oxidation reactions via the Mars-van Krevelen mechanism. However, there is currently no function that maps oxygen vacancy formation energies to CO oxidation barriers. We have compiled a data set for CO oxidation on doped and pristine metal oxide surfaces as well as metal/metal oxide interface sites using density functional theory. Based on this data, we can predict CO oxidation barriers from oxygen vacancy formation energies using a Bronsted-Evans-Polanyi relation with a mean absolute error of 14 kJ/mol. Contrary to what is known for reactions on metal surfaces, we find that the scaling parameter alpha that describes the lateness of the transition state for CO oxidation on metal oxides is not constant. (C) 2019 Elsevier Inc. All rights reserved.