Binding sites, geometry, and energetics of propene at nanoparticulate Au/TiO2

Darren M. Driscoll, Wenjie Tang, Steven P. Burrows, Dimitar A. Panayotov, Matthew Neurock, Monica McEntee, John R. Morris

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Surface adsorption and activation of propene, to catalytically produce propene oxide, is the first step in the industrially important gas-phase epoxidation reaction. Motivated by the significant practical importance of this reaction, site-specific adsorption of propene on nanoparticulate titania-supported Au (Au/TiO2) has been systematically characterized through Fourier transform infrared (FTIR) spectroscopy and density functional theoretical (DFT) calculations. The infrared spectra, recorded during propene uptake at low surface temperatures, and DFT calculations identified two distinct propene-surface binding motifs. Propene was found to bind to the surface through a π-interaction at TiO2 sites remote from the Au particles and through a (πσ)-interaction at a single atomic Au site, distinguishable through the stretching frequency of the propene double bond. Temperature-programmed desorption and calculated binding enthalpies for the minimum-energy configurations revealed the propene-Au interaction to have a stronger binding energy relative to the propene-TiO2 interaction. Upon coordination to Au, the double bond of propene was found to weaken and elongate, a possible first step in the activation and epoxidation to form propene oxide. (Chemical Equation Presented).

Original languageEnglish (US)
Pages (from-to)1683-1689
Number of pages7
JournalJournal of Physical Chemistry C
Volume121
Issue number3
DOIs
StatePublished - Jan 26 2017

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

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