1. A Water-Promoted Mars-van Krevelen Reaction Dominates Low-Temperature CO Oxidation over Au-Fe 2 O 3 but Not over Au-TiO 2 .
- Author
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Holm A, Davies B, Boscolo Bibi S, Moncada F, Halldin-Stenlid J, Paškevičius L, Claman V, Slabon A, Tai CW, Campos Dos-Santos E, and Koroidov S
- Abstract
We provide experimental evidence that is inconsistent with often proposed Langmuir-Hinshelwood (LH) mechanistic hypotheses for water-promoted CO oxidation over Au-Fe
2 O3 . Passing CO and H2 O, but no O2 , over Au-γ-Fe2 O3 at 25 °C, we observe significant CO2 production, inconsistent with LH mechanistic hypotheses. Experiments with H2 18 O further show that previous LH mechanistic proposals cannot account for water-promoted CO oxidation over Au-γ-Fe2 O3 . Guided by density functional theory, we instead postulate a water-promoted Mars-van Krevelen (w-MvK) reaction. Our proposed w-MvK mechanism is consistent both with observed CO2 production in the absence of O2 and with CO oxidation in the presence of H2 18 O and16 O2 . In contrast, for Au-TiO2 , our data is consistent with previous LH mechanistic hypotheses., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)- Published
- 2024
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