Mechanism of water oxidation catalyzed by cobalt-intercalated layered MnO₂: confinement and intercalant local ordering

To lower the overpotential is a persistent goal for (photo)electrochemistry reactions, which can be facilitated by selectively stabilizing one reaction intermediate over another. In this mechanistic SCAN+rVV10^1,2 study of the oxygen evolution reaction (OER) catalysed by cobalt-intercalated layered MnO₂, we show that confinement effects and local cobalt atomic ordering in the interlayer space can be used to tune the adsorption energies of O, OH, and OOH reaction intermediates and the scaling relationship between them. Interlayer confinement destabilizes the OER intermediates, but clustering Co atoms can selectively stabilize OOH. With considering both effects, our model predicts an overpotential of 0.30 V, in excellent agreement with the experimental result of 0.36 V³. In addition to giving mechanistic explanation for experimental findings, these insights illuminate a route for engineering non-toxic precious-metal-free catalysts through designed layered materials.
¹J. Sun, A. Ruzsinszky, J. P. Perdew, Physical Review Letters 115, 036402 (2015).
²H. Peng, Z. Yang, J. P. Perdew, and J Sun Phys. Rev. X 6, 041005 (2016)
³A. C. Thenuwara, D. R. Strongin, ACS Catalysis 6, 7739 (2016).