Role of Water Solvation on the Key Intermediates Catalyzing Oxygen Evolution on RuO2
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di-liberto-et-al-2023.pdf
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Published version
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Author(s)
Di Liberto, Giovanni
Pacchioni, Gianfranco
Shao-Horn, Yang
Giordano, Livia
Date Issued
May 18, 2023
Journal
The Journal of Physical Chemistry C
Publisher
American Chemical Society
Citation
Giovanni Di Liberto, Gianfranco Pacchioni, Yang Shao-Horn, and Livia Giordano
The Journal of Physical Chemistry C 2023 127 (21), 10127-10133
DOI: 10.1021/acs.jpcc.3c02733
Version
Final published version
Abstract
RuO2 and IrO2 are among the most active catalysts for the Oxygen Evolution Reaction (OER). Recently, it was demonstrated that the catalytic surface of these oxides plays a role in the reaction, where a hydrogen bond with a neighbor OH group stabilizes an unconventional −OO intermediate (−OO–H), prior to O2 evolution. Quantum chemical calculations neglecting solvation effects indicated that this intermediate is more stable than the conventional −OOH, and that deprotonation of the stabilizing −OH is the rate limiting step for OER on RuO2(110) and RuO2(100). In this work, we investigate the role of water molecules on the relative stability of −OOH and −OO–H oxygenates on RuO2 (110) by means of density functional theory calculations combined with ab initio Molecular Dynamics simulations (AIMD). We show that the two intermediates participate in a hydrogen bonding network with water to a similar extent, but leading to different interfacial water structures, with possible implications on interfacial proton dynamics and reaction kinetics. Moreover, −OOH can spontaneously convert to −OO–H through a process mediated by water, demonstrating the critical role of explicitly including water in the model. This study provides further mechanistic insights on the role of the oxide surface chemistry in the OER mechanism and highlights the importance of explicitly treating the catalyst/water interfaces including dynamical aspects to assess the stability and the interconversion mechanism of key surface species, since the adoption of static solvation approaches tends to overestimate the energetic difference between −OOH and −OO–H reaction intermediates.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1021/acs.jpcc.3c02733
