The oxygen evolution reaction (OER) is of central importance for the sustainable production of fuels and high-value commodity chemicals because it provides the protons and electrons for reduction processes, such as the hydrogen evolution reaction or the conversion of carbon dioxide. The OER is slow and needs to be promoted by catalysts. A key challenge is the development of OER catalysts that are simultaneously stable and efficient. To facilitate the design of such catalysts, it is essential to develop a better mechanistic understanding of the OER. The O-O bond formation step is often considered the rate-limiting step of this reaction. It is therefore critical to understand the process of O-O bond formation. In this work, we explored how the O-O bond formation mechanism on Co-oxide-based electrocatalysts depends on applied electrode potential. Using operando infrared spectroscopy and electroanalytical methods, we found a potential-induced switch in the pathway of O-O bond formation. We will discuss the implications of our mechanistic findings for the design of stable and efficient OER catalysts.

Potential-dependence of the mechanism of the oxygen evolution reaction (OER) on Co-oxide based electrocatalysts

ACS Spring 2022

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