TY - JOUR
T1 - Acid-Base Chemistry of a Model IrO2 Catalytic Interface
AU - Raman, Abhinav S.
AU - Selloni, Annabella
N1 - Funding Information: This work was supported by DoE BES, CSGB Division, under Award DESC0007347, with further support from the Computational Chemical Center: Chemistry in Solution and at Interfaces, funded by DoE under Award DESC0019394. The authors acknowledge the use of computational resources (Stampede2 at TACC) provided by the Extreme Science and Engineering Discovery Environment (XSEDE) supported though the National Science Foundation (NSF) under Award CHE210079, and the National Energy Research Scientific Computing Center (NERSC), under DoE Contract DE-AC02-05cH11231. We also acknowledge the use of the Princeton Research Computing resources at Princeton University which is a consortium of groups led by the Princeton Institute for Computational Science and Engineering (PICSciE) and Office of Information Technology’s Research Computing. Publisher Copyright: © 2023 American Chemical Society.
PY - 2023/9/7
Y1 - 2023/9/7
N2 - Iridium oxide (IrO2) is one of the most efficient catalytic materials for the oxygen evolution reaction (OER), yet the atomic scale structure of its aqueous interface is largely unknown. Herein, the hydration structure, proton transfer mechanisms, and acid-base properties of the rutile IrO2(110)-water interface are investigated using ab initio based deep neural-network potentials and enhanced sampling simulations. The proton affinities of the different surface sites are characterized by calculating their acid dissociation constants, which yield a point of zero charge in agreement with experiments. A large fraction (≈80%) of adsorbed water dissociation is observed, together with a short lifetime (≈0.5 ns) of the resulting terminal hydroxy groups, due to rapid proton exchanges between adsorbed H2O and adjacent OH species. This rapid surface proton transfer supports the suggestion that the rate-determining step in the OER may not involve proton transfer across the double layer into solution, as indicated by recent experiments.
AB - Iridium oxide (IrO2) is one of the most efficient catalytic materials for the oxygen evolution reaction (OER), yet the atomic scale structure of its aqueous interface is largely unknown. Herein, the hydration structure, proton transfer mechanisms, and acid-base properties of the rutile IrO2(110)-water interface are investigated using ab initio based deep neural-network potentials and enhanced sampling simulations. The proton affinities of the different surface sites are characterized by calculating their acid dissociation constants, which yield a point of zero charge in agreement with experiments. A large fraction (≈80%) of adsorbed water dissociation is observed, together with a short lifetime (≈0.5 ns) of the resulting terminal hydroxy groups, due to rapid proton exchanges between adsorbed H2O and adjacent OH species. This rapid surface proton transfer supports the suggestion that the rate-determining step in the OER may not involve proton transfer across the double layer into solution, as indicated by recent experiments.
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U2 - 10.1021/acs.jpclett.3c02001
DO - 10.1021/acs.jpclett.3c02001
M3 - Article
C2 - 37616464
SN - 1948-7185
VL - 14
SP - 7787
EP - 7794
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 35
ER -