2026-10-30 パシフィック・ノースウェスト国立研究所（PNNL）
TiO2(101) single crystals and thin catalyst layers yield ketene with essentially no acetone. As acetic acid saturates deeper layers in thicker TiO2 films, ketene undergoes more interparticle collisions and acetone formation increases. (Image by Zdenek Dohnálek | Pacific Northwest National Laboratory)
＜関連情報＞
- https://www.pnnl.gov/publications/ketene-gas-phase-intermediate-acetic-acid-ketonization
- https://www.nature.com/articles/s41467-026-77945-8
TiO2上での酢酸ケトン化における気相中間体としてのケテン Ketene as a gas phase intermediate in acetic acid ketonization on TiO2
Jiayan Xu, William JI DeBenedetti, Xingyu Wang, Yiqing Wu, Libor Kovarik, Christopher R. O’Connor, Feng Gao, Janos Szanyi, Yong Wang, Annabella Selloni, Greg A. Kimmel & Zdenek Dohnálek
Nature Communications Published:28 October 2026
DOI:https://doi.org/10.1038/s41467-026-77945-8
Abstract
Reactive gas-phase intermediates are often underappreciated in heterogeneous catalysis, despite their potential to control key catalytic steps. Here, we provide direct experimental evidence that ketene can act as an intermediate in acetic acid ketonization, a mechanism that has long been debated. Using faceted TiO2(101) nanoparticles assembled into layers of controlled thickness, we show that ketene, formed from surface acetate, migrates through interparticle voids via desorption-readsorption events before reacting with surface acetate to yield acetone. Surface science and reactor studies reveal a direct correlation between ketene and acetone production and the depth to which the particle layers are saturated. Ab initio calculations support ketene’s reactivity via low-barrier coupling pathways that converge on a common β-ketoacid intermediate. Here, we show that ketene can act as a mobile gas-phase intermediate and underscore the broader importance of spatially decoupled elementary steps in determining reactivity and selectivity in catalytic systems.
