Methanol Decomposition on TiO₂ Under Ambient Conditions: Cooperative Proton Transfer at Hydrated Interfaces
Abstract
Methanol decomposition is a benchmark reaction for understanding surface‐mediated redox chemistry and photocatalytic processes on oxide materials. While its mechanism on TiO₂ has been extensively studied under ultra‐high‐vacuum (UHV) conditions, the reaction pathway under ambient, liquid‐phase environments remains largely unexplored. Here, we investigate the photocatalytic decomposition of methanol on rutile TiO₂ (110) following direct adsorption from liquid solution by combining surface‐sensitive sum frequency generation (SFG) spectroscopy with density functional theory (DFT) calculations. SFG measurements identify methoxy as the dominant surface species under these conditions. DFT calculations reveal that cooperative hydrogen‐bonding interactions stabilize both the transition state and the dissociated configuration, leading to a systematic reduction in activation barriers. Concurrently, localized excess charge facilitates proton transfer through dynamic redistribution along the reaction coordinate, thereby lowering the barrier for O─H bond cleavage and stabilizing reaction intermediates. Under resonant bandgap excitation, methoxy undergoes structural reorientation followed by oxidation to form a stable surface hydroxymethyl species. DFT calculations further demonstrate that interfacial water and hydroxyl groups stabilize localized charge carriers, reduce activation barriers, and promote proton‐coupled electron transfer. These findings provide molecular‐level insight into the role of interfacial hydration in governing photocatalytic reaction pathways at oxide–liquid interfaces.
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BibTeX
@article{salarinasab2026methanol,
title = {{Methanol Decomposition on TiO₂ Under Ambient Conditions: Cooperative Proton Transfer at Hydrated Interfaces}},
author = {Milad Salarinasab and Julian Andreas Hochhaus and Jing Wang and Aimeric Ouvrard and Anas Akhtar and Michele Capra and Kristina Tschulik and Carsten Westphal and Mirko Cinchetti and Bo Wen and Li‐min Liu and Zhe Wang and Ahmed Ghalgaoui},
journal = {Angewandte Chemie International Edition},
year = {2026},
month = sep,
doi = {10.1002/anie.3448039},
url = {https://hal.science/hal-05755116v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Methanol Decomposition on TiO₂ Under Ambient Conditions: Cooperative Proton Transfer at Hydrated Interfaces
AU - Milad Salarinasab
AU - Julian Andreas Hochhaus
AU - Jing Wang
AU - Aimeric Ouvrard
AU - Anas Akhtar
AU - Michele Capra
AU - Kristina Tschulik
AU - Carsten Westphal
AU - Mirko Cinchetti
AU - Bo Wen
AU - Li‐min Liu
AU - Zhe Wang
AU - Ahmed Ghalgaoui
PY - 2026
DA - 2026/09/07
JO - Angewandte Chemie International Edition
DO - 10.1002/anie.3448039
UR - https://hal.science/hal-05755116v1
AB - Methanol decomposition is a benchmark reaction for understanding surface‐mediated redox chemistry and photocatalytic processes on oxide materials. While its mechanism on TiO₂ has been extensively studied under ultra‐high‐vacuum (UHV) conditions, the reaction pathway under ambient, liquid‐phase environments remains largely unexplored. Here, we investigate the photocatalytic decomposition of methanol on rutile TiO₂ (110) following direct adsorption from liquid solution by combining surface‐sensitive sum frequency generation (SFG) spectroscopy with density functional theory (DFT) calculations. SFG measurements identify methoxy as the dominant surface species under these conditions. DFT calculations reveal that cooperative hydrogen‐bonding interactions stabilize both the transition state and the dissociated configuration, leading to a systematic reduction in activation barriers. Concurrently, localized excess charge facilitates proton transfer through dynamic redistribution along the reaction coordinate, thereby lowering the barrier for O─H bond cleavage and stabilizing reaction intermediates. Under resonant bandgap excitation, methoxy undergoes structural reorientation followed by oxidation to form a stable surface hydroxymethyl species. DFT calculations further demonstrate that interfacial water and hydroxyl groups stabilize localized charge carriers, reduce activation barriers, and promote proton‐coupled electron transfer. These findings provide molecular‐level insight into the role of interfacial hydration in governing photocatalytic reaction pathways at oxide–liquid interfaces.
SN - 1433-7851
SN - 1521-3773
ER -