The oxygen evolution reaction (OER) provides the reducing equivalents necessary for hydrogen gas generation and carbon dioxide reduction, among other means of renewable energy storage. Metal oxides catalysts, such as those based on cobalt, may drive OER electrochemically, with such schemes categorically relying upon additional bases and buffers. These bases not only serve as supporting electrolytes but also interact directly with the protons produced by and involved in OER. This multifaceted role is explored herein with acid-stable and acid-unstable metal oxide catalysts, to clarify how processes of self-healing and lattice-oxygen protonation may contribute to electrochemical OER activity. Relying upon rotating disc electrodes and various bases, we show how OER activity may be modulated by mass transport effects and pK<sub>a</sub> value, which direct both diffusion-layer pH gradients and the deprotonation of reactive intermediates. This dual role of bases in electrochemical OER highights important design principles for next-generation catalysts, as well as provides insight into how protons activity around electodes may be affected and exploited.

Dual role of Lewis bases in electrochemical oxygen evolution on metal oxide catalysts

ACS Spring 2022

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