(383b) Development of the Oxygen Reduction Reaction Mechanism on Pt(111) Using Dft

Despite being the subject of numerous studies, the reaction mechanism of the oxygen reduction reaction on Pt electrodes is still not clear. Current knowledge of the reaction has been derived almost entirely from current-voltage relationships because of the inaccessibility of the electrode | electrolyte interface to surface probes. Although a few Pt-alloy catalysts exhibiting superior performance to pure Pt have been identified, the lack of a clear mechanism has hindered ORR catalyst design.

DFT offers great promise in advancing the understanding of the oxygen reduction reaction. The challenge, however, lies in developing a model that represents the physics of the interface, yet is not so complex that its use is prohibitive. In this talk, we will present the results of our calculations of oxygen reduction on Pt(111), in which the solution is modeled by weakly adsorbed protonated water clusters and the interfacial charge gradient modeled with homogeneous electric fields. These calculations favor a pathway in which an initial proton transfer step is followed by a dissociation step. We will then discuss how these results complement previous experimental data.