Year: 2014
Type: article
Abstract: We provide direct evidence of a water-mediated reaction mechanism for room-temperature CO oxidation over Au/TiO2 catalysts. A hydrogen/deuterium kinetic isotope effect of nearly 2 implicates O-H(D) bond breaking in the rate-determining step. Kinetics and in situ infrared spectroscopy experiments showed that the coverage of weakly adsorbed water on TiO2 largely determines catalyst activity by changing the number of active sites. Density functional theory calculations indicated that proton transfer at the metal-support interface facilitates O2 binding and activation; the resulting Au-OOH species readily reacts with adsorbed Au-CO, yielding Au-COOH. Au-COOH decomposition involves proton transfer to water and was suggested to be rate determining. These results provide a unified explanation to disparate literature results, clearly defining the mechanistic roles of water, support OH groups, and the metal-support interface.
Source: Science
Institutions: Trinity University, University of Houston
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: G102163711, NSF/DOE Advanced Combustion Engines - Tailoring Catalyst Composition and Architecture for Conversion of Pollutants from Low Temperature Diesel Combustion Engines, G1286251239, RUI: Preparation and Characterization of New Heterogeneous Bimetallic Au-M Catalysts for Selective Oxidations and Hydrogenations, G2287611682, G262962599, G426311843, RUI: Preparation and Characterization of Dendrimer Templated Au-M Nanoparticles and Catalysts, RUI: Quantifying Electron Donation in Metal-Support Interactions utilizing CO Adsorption Studies and Hammet Relationships for Catalyzed Organic Transformations, The Wisdom of Athena: Extending the scientific impact of the NSF's most cost-effective supercomputer, Enhancing Computational Science Opportunities on NSF's Kraken, G4935979752, Augment the Kraken! Increasing the scientific capability and capacity of the NSF's most powerful supercomputer, G498139845, G5387317844, G5532414758, A National Institute for Computational Sciences to Provide Leading-Edge Computational Support for Breakthrough Science and Engineering Research, XSEDE: eXtreme Science and Engineering Discovery Environment, G6848031779, G6918803902, G7579982596, G7583137537, G7945140825, G8274177341, G8753961536, G8906138249, G947877169, G969889393
OpenAlex ID: W2017097251