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Kinetics of H 2 Adsorption at the Metal–Support Interface of Au/TiO 2 Catalysts Probed by Broad Background IR Absorbance
Author(s) -
MahdaviShakib Akbar,
Kumar K. B. Sravan,
Whittaker Todd N.,
Xie Tianze,
Grabow Lars C.,
Rioux Robert M.,
Chandler Bert D.
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202013359
Subject(s) - adsorption , absorbance , catalysis , kinetics , chemistry , metal , analytical chemistry (journal) , proton , inorganic chemistry , materials science , physics , organic chemistry , chromatography , quantum mechanics
H 2 adsorption on Au catalysts is weak and reversible, making it difficult to quantitatively study. We demonstrate H 2 adsorption on Au/TiO 2 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 2 adsorption; adsorption equilibrium constants are comparable to volumetric adsorption measurements. H 2 adsorption kinetics measured with the BBA show a lower E app value (23 kJ mol −1 ) for H 2 adsorption than previously reported from proxy H/D exchange (33 kJ mol −1 ). 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 2 adsorption at the Au/TiO 2 interface.