The efficiency of catalysts is driven by the reactivity of intermediate species in the catalytic pathway. By recognizing that many reactions, such as H2 production and oxidation and O2, N2 and CO2 reduction, involve electron, proton, and hydride transfers, we can use a thermodynamic approach to avoid high-energy and low-energy intermediates. This approach is based on the knowledge of pKa values, hydride donor abilities, redox potentials, and other relevant thermodynamic properties. These quantities can be accurately calculated using isodesmic reaction schemes employing DFT calculations, whereby one or a few reference complexes are used, and the desired property is determined with respect to the references. The reference values to be used in the isodesmic reactions are determined using high accuracy ab initio methods. We will show examples from our labs of catalysts for the O2 reduction reaction and will demonstrate how this approach can used to obtain design points for improving catalyst efficiency.

Thermodynamic approach for exploring catalytic pathways using high accuracy computational methods

251st National Meeting (2016)

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