Bonding, mechanism and kinetics of water oxidation over oxide catalysts

Abstract

We have used quantum mech. models to elucidate the mechanisms by which leading heterogeneous and mol. electrocatalysts facilitate the chem. conversions required for the oxidn. of water and redn. of protons and CO_2. For the oxidn. of water to dioxygen over acid-stable IrO_2, fixed-electrochem.-potential simulations including solvation and transition states predict the chem. evolution of the solid-electrolyte interface as a function of potential. The activation barriers for reactions of surface oxo and hydroxo groups with each other and with water are discussed, and compared to mechanisms over other catalysts. Microkinetic models populated by potential-dependent rate and equil. consts. enable comparisons to exptl. Tafel plots.

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