Infrared studies of propene and propene oxide adsorption on nanoparticulate Au/TiO2

SURFACE SCIENCE

卷:652

Article

Panayotov, Dimitar¹  McEntee, Monica²  Burrows, Steve³  Driscoll, Darren³  Tang, Wenjie⁴  Neurock, Matthew⁴  Morris, John³ 

[1] Bulgarian Acad Sci, Inst Gen & Inorgan Chem, BU-1113 Sofia, Bulgaria

[2] US Army, Edgewood Chem Biol Ctr, Aberdeen Proving Ground, MD 21010 USA

[3] Virginia Tech, Dept Chem, Blacksburg, VA 24061 USA

[4] Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA

关键词: Propene;    Propene oxide;    Adsorption;    Au/TiO2;    Infrared spectroscopy;    Density functional theory;   

DOI  :  10.1016/j.susc.2016.03.033

来源: Elsevier

【 摘 要 】

Direct gas-phase epoxidation of propene to propene oxide over a heterogeneous catalyst holds the potential to revolutionize production of one of the world's major commodity chemicals. New research into fundamental aspects of propene chemistry on nanoparticulate catalysts will help guide strategies for materials development. In the current study, Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) have been employed to explore the molecular-level details of propene and propene oxide binding at a Au/TiO2 catalyst. Competitive binding studies for propene and carbon monoxide reveal that propene readily displaces CO from: first, interfacial Au parallel to TiO2 sites, then low coordinated Au sites at particulate corners and edges, and finally terrace regions of the particles. DFT calculations show that the C=C bond of propene weakens upon coordination to Au, which suggests that these sites may activate the molecule for epoxidation. Like propene, propene oxide adsorbs on both Au sites and Ti sites. In addition, Ti-OH sites also readily bind the oxide. However, competitive binding experiments show that the propene oxide adsorption is favored relative to propene on all sites, which would likely passivate the, catalyst at room temperature. (C) 2016 Published by Elsevier B.V.

【 授权许可】

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