QM metadynamics full solvent simulations of the oxygen reduction reaction (ORR); atomistic description of the electrode-electrolyte interface (EEI)

Abstract

Advances in theory and methods of quantum mechanics and in supercomputers are making it practical to consider first principles (de novo) predictions of the mechanisms of complex catalytic reactions. We will highlight some recent advances in such methodologies including: QM Metadynamics calcns. of free energies of electrocatalysis at operational temp. and potential Grand canonical QM calcns. of electrochem. catalysis at const. potential (instead of const. nos. of electrons), which we will illustrate with recent applications to fuel cells: We will discuss the activation barrirs for the key steps of the oxygen redn. reaction (ORR) on Pt(111) dissocg. O_2, forming OH and forming H_2O product. In particular, we will ext. from the simulations the predicted XPS chem. shifts and the OH vibrational frequencies for the species in the electrolyte that might be compared to future exptl. measurements to understand the nature of the electrode-electrolyte interface (EEI).