RuO2 and IrO2 are among the best catalysts for the oxygen evolution reaction (OER), an electrochemical reaction that limits the efficiency of water splitting. The high activity of these rutile oxides has been attributed to their ability to stabilize the OER intermediates via electroadsorption which involves related elementary proton and electron transfer steps. However, the rates (kinetics) of the individual proton and electron transfer steps related to the oxygen electroadsorption are still unclear. In this presentation, we present our measurements of these kinetics on well-defined RuO2 and IrO2 surfaces. We use rate-dependent cyclic voltammograms to extract the rates of the oxygen electroadsorption on RuO2 and IrO2. Well-defined surfaces are used to minimize convolution from different facets. We further identify the pathway and related fundamental rate laws by investigating the influence of different electrolytes on kinetics. Our results provide insights into the kinetics of oxygen electroadsorption on oxides and the fundamental origin of the sluggishness in the OER kinetics.

Measurements of oxygen electroadsorption kinetics on RuO2(110) and IrO2(110)

2019 Spring National Meeting

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