(544dm) Metal-Oxide Supported Pt Catalysts for Oxygen Reduction Reaction: A Density Functional Theory Approach

Sluggish kinetics of the Oxygen Reduction Reaction (ORR) at the cathode electrode are widely recognized as a major bottleneck for Polymer Electrolyte Membrane (PEM) fuel cells. Currently platinum and its alloys are among the most active catalysts. However even these do not attain the fundamental limit of activity dictated by thermodynamics and cause prohibitively high fuel cells costs in applications such as transportation. We perform an atomistic surface analysis of a novel catalyst design using Density Functional Theory (DFT) based approach. Using the OH* descriptor, we compare adsorption characteristics of a transition metal oxide TiO₂ supported platinum catalyst with bulk Pt(111). Since the variability of transition metals creates diverse properties in metal-oxides, such supports induce a finite strain on the overlying Pt that affects adsorption energetics of the ORR. We define activity by the limiting potential as a function of Pt layer thickness and use this to show how we can tune adsorption on the surface. We also use ensemble error estimation within BEEF to report uncertainties relating to these calculations.