Toward resolving the RuO₂/IrO₂ oxygen evolution activity puzzle: critical roles of spin polarization and exchange-correlation functional accuracy.
- 1Department of Materials Science and Engineering, City University of Hong Kong Hong Kong SAR 999077 China [email protected].
- 2School of Energy and Environment, City University of Hong Kong Hong Kong SAR 999077 China.
Abstract
The oxygen evolution reaction (OER) activity ordering of RuO₂ and IrO₂ is well established experimentally, yet density functional theory calculations have persistently failed to reproduce this trend, undermining computational catalyst design. Here, we investigate this discrepancy by evaluating OER thermodynamic and kinetic activities of IrO₂ and RuO₂ using four exchange-correlation (XC) functionals (PBE, RPBE, r2SCAN, and MS2-rVV10) under spin-polarized and spin-unpolarized conditions. Spin polarization selectively stabilizes the O* intermediate on IrO₂ while leaving RuO₂ comparatively unaffected, and neglecting spin effects yields unphysically low kinetic barriers for IrO₂. Among the four functionals, only MS2-rVV10 reproduces the experimentally observed activity trend in both thermodynamic and kinetic analyses. We trace these failures to a systematic correlation between adsorption-energy errors and deviations in the predicted activity trend. Notably, the OOH*-OH* scaling offset and theoretical limiting potential are themselves XC-functional dependent, cautioning against cross-functional comparison of overpotentials. Cross-code benchmarks rule out numerical implementation as the error source, while higher-rung functionals progressively overestimate Ru local magnetic moments in RuO₂, introducing additional errors. This work establishes accurate exchange-correlation functionals and proper spin-polarization treatment as prerequisites for reliable OER catalyst design.
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BibTeX
@article{xie2026toward,
title = {{Toward resolving the RuO₂/IrO₂ oxygen evolution activity puzzle: critical roles of spin polarization and exchange-correlation functional accuracy.}},
author = {Xiaokun Xie and Jiashun Wu and Zhenbin Wang},
journal = {Chemical science},
year = {2026},
month = oct,
doi = {10.1039/d6sc04703c},
url = {https://europepmc.org/article/MED/42891083},
note = {CC BY},
}
RIS
TY - JOUR
TI - Toward resolving the RuO₂/IrO₂ oxygen evolution activity puzzle: critical roles of spin polarization and exchange-correlation functional accuracy.
AU - Xiaokun Xie
AU - Jiashun Wu
AU - Zhenbin Wang
PY - 2026
DA - 2026/10/09
JO - Chemical science
DO - 10.1039/d6sc04703c
UR - https://europepmc.org/article/MED/42891083
AB - The oxygen evolution reaction (OER) activity ordering of RuO₂ and IrO₂ is well established experimentally, yet density functional theory calculations have persistently failed to reproduce this trend, undermining computational catalyst design. Here, we investigate this discrepancy by evaluating OER thermodynamic and kinetic activities of IrO₂ and RuO₂ using four exchange-correlation (XC) functionals (PBE, RPBE, r2SCAN, and MS2-rVV10) under spin-polarized and spin-unpolarized conditions. Spin polarization selectively stabilizes the O* intermediate on IrO₂ while leaving RuO₂ comparatively unaffected, and neglecting spin effects yields unphysically low kinetic barriers for IrO₂. Among the four functionals, only MS2-rVV10 reproduces the experimentally observed activity trend in both thermodynamic and kinetic analyses. We trace these failures to a systematic correlation between adsorption-energy errors and deviations in the predicted activity trend. Notably, the OOH*-OH* scaling offset and theoretical limiting potential are themselves XC-functional dependent, cautioning against cross-functional comparison of overpotentials. Cross-code benchmarks rule out numerical implementation as the error source, while higher-rung functionals progressively overestimate Ru local magnetic moments in RuO₂, introducing additional errors. This work establishes accurate exchange-correlation functionals and proper spin-polarization treatment as prerequisites for reliable OER catalyst design.
SN - 2041-6520
SN - 2041-6539
ER -