Kinetics of H 2 Adsorption at the Metal-Support Interface of Au/TiO 2 Catalysts Probed by Broad Background IR Absorbance

H adsorption on Au catalysts is weak and reversible, making it difficult to quantitatively study. We demonstrate H adsorption on Au/TiO catalysts results in electron transfer to the support, inducing shifts in the FTIR background. This broad background absorbance (BBA) signal is used to quantify H a...

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Published inAngewandte Chemie International Edition Vol. 60; no. 14; pp. 7735 - 7743
Main Authors Mahdavi-Shakib, Akbar, Kumar, K B Sravan, Whittaker, Todd N, Xie, Tianze, Grabow, Lars C, Rioux, Robert M, Chandler, Bert D
Format Journal Article
LanguageEnglish
Published Germany 29.03.2021
Subjects
metal-support interface
gold catalyst
hydroxyl groups
hydrogen activation
infrared spectroscopy
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Summary:H adsorption on Au catalysts is weak and reversible, making it difficult to quantitatively study. We demonstrate H adsorption on Au/TiO catalysts results in electron transfer to the support, inducing shifts in the FTIR background. This broad background absorbance (BBA) signal is used to quantify H adsorption; adsorption equilibrium constants are comparable to volumetric adsorption measurements. H adsorption kinetics measured with the BBA show a lower E value (23 kJ mol ) for H adsorption than previously reported from proxy H/D exchange (33 kJ mol ). We also identify a previously unreported H-O-H bending vibration associated with proton adsorption on electronically distinct Ti-OH metal-support interface sites, providing new insight into the nature and dynamics of H adsorption at the Au/TiO interface.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.202013359