Temporal Programming of Interfacial States Reveals a Hidden Formate Pathway from CO2 Reduction on Palladium
4 affiliations
- 1Department of Chemistry
- 2University of Texas at Austin
- 3Center for Electrochemistry
- 4Texas Materials Institute
Abstract
Controlling electrocatalytic selectivity requires not only tuning catalyst composition but also controlling the interfacial states that emerge during operation. Here, using bulk Pd as a model system for electrochemical CO 2 reduction reaction (CO 2 RR), we show that poor steady-state formate production emerges from time-dependent evolution of the electrochemical interface. Pd initially exhibits appreciable formate activity but rapidly accumulates strongly bound CO and evolves toward a CO-rich, formate-inactive state. Although substantial sorbed H persists during this evolution, its oxidation shifts to increasingly positive potentials with increasing CO coverage, indicating reduced electrochemical accessibility and reactivity of H at the CO-covered interface. Density functional theory shows that CO-rich configurations are thermodynamically favored under cathodic conditions, while increasing CO coverage destabilizes early intermediates of both the formate and CO pathways. Dynamic potential modulation temporally separates surface-state preparation from catalytic turnover: anodic excursions remove accumulated CO, and subsequent cathodic polarization repeatedly accesses a CO-depleted state that is not thermodynamically favored at the reaction potential. This strategy produces an approximately 230-fold enhancement in formate partial current density relative to static operation. Within this dynamically accessible low-CO regime, formate activity further correlates with sorbed-H availability. These results reveal a hierarchical interfacial control in which CO coverage gates pathway accessibility while hydrogen availability modulates formate activity, demonstrating how temporal control can access catalytic states and reaction pathways hidden under steady-state operation.
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BibTeX
@misc{lee2026temporal,
title = {{Temporal Programming of Interfacial States Reveals a Hidden Formate Pathway from CO2 Reduction on Palladium}},
author = {Hyein Lee and Satoshi Ohtsuka and Wenrui Chai and Tamilselvi Gurusamy and Johan I. Martinez and Graeme Henkelman and Hang Ren},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008360/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008360/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Temporal Programming of Interfacial States Reveals a Hidden Formate Pathway from CO2 Reduction on Palladium
AU - Hyein Lee
AU - Satoshi Ohtsuka
AU - Wenrui Chai
AU - Tamilselvi Gurusamy
AU - Johan I. Martinez
AU - Graeme Henkelman
AU - Hang Ren
PY - 2026
DA - 2026/09/06
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008360/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008360/v1
AB - Controlling electrocatalytic selectivity requires not only tuning catalyst composition but also controlling the interfacial states that emerge during operation. Here, using bulk Pd as a model system for electrochemical CO 2 reduction reaction (CO 2 RR), we show that poor steady-state formate production emerges from time-dependent evolution of the electrochemical interface. Pd initially exhibits appreciable formate activity but rapidly accumulates strongly bound CO and evolves toward a CO-rich, formate-inactive state. Although substantial sorbed H persists during this evolution, its oxidation shifts to increasingly positive potentials with increasing CO coverage, indicating reduced electrochemical accessibility and reactivity of H at the CO-covered interface. Density functional theory shows that CO-rich configurations are thermodynamically favored under cathodic conditions, while increasing CO coverage destabilizes early intermediates of both the formate and CO pathways. Dynamic potential modulation temporally separates surface-state preparation from catalytic turnover: anodic excursions remove accumulated CO, and subsequent cathodic polarization repeatedly accesses a CO-depleted state that is not thermodynamically favored at the reaction potential. This strategy produces an approximately 230-fold enhancement in formate partial current density relative to static operation. Within this dynamically accessible low-CO regime, formate activity further correlates with sorbed-H availability. These results reveal a hierarchical interfacial control in which CO coverage gates pathway accessibility while hydrogen availability modulates formate activity, demonstrating how temporal control can access catalytic states and reaction pathways hidden under steady-state operation.
ER -