Facilitating the Rational Design of Active Sites for the Oxygen Evolution Reaction on 3d Transition Metal Oxide Catalysts

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The proposed work will involve the development of new methods as well as the application of existing methods to obtain an understanding of how the activity for the oxygen evolution reaction (OER) of an active site on a 3D transition metal oxide surface is related to the structure (geometry and composition) of the active site. This would enable us to identify the properties of an active site leading to highest OER activity, as well as the mechanism by which the reaction occurs on such a site. This would provide valuable guidance for future experimental and computational search for a practical heterogeneous oxygen evolution catalyst. Additionally we will seek an understanding of this structure-activity relationship at the quantum chemical level. Periodic density functional theory (DFT) calculations will be used to determine the energetics of catalytic intermediates and rate constants for reaction steps which will then be used in a kinetic model to predict the turnover frequency and rate controlling step of the catalytic cycle for several different mechanisms. The calculations will include interactions with a continuum model of the electrolyte and will be performed on charged as well as neutral states of the active site. This latter task will require the development of a method for calculating free energies of charged active sites within the framework of periodic DFT, a frequently encountered situation in catalysis at the solid-liquid interface for which a universally applicable and computationally inexpensive approach does not currently exist. Novel constraining methods for examining the local electronic structure of the active site that were previously developed in our group will be used and further developed to understand how the electronic structure varies across the different metal oxides and how this relates to the catalytic activity.