title: Selective Autooxidation of Ethanol over Titania-Supported Molybdenum Oxide Catalysts: Structure and Reactivity.
abstract: We study the selective catalytic oxidation of ethanol with air as a sustainable alternative route to acetaldehyde. The reaction is catalysed by molybdenum oxide supported on titania, in a flow reactor under ambient pressure. High selectivity to acetaldehyde (70%-89%, depending on the Mo loading) is obtained at 150 °C. Subsequently, we investigate the structure/performance relationship for various molybdenum oxide species using a combination of techniques including diffuse reflectance UV-visible, infrared, X-ray photoelectron spectroscopies, X-ray diffraction and temperature programmed reduction. As their surface density increases, the monomeric molybdenum oxide species undergo two-dimensional and three-dimensional oligomerisation. This results in polymolybdates and molybdenum oxide crystallites. Importantly, the ethanol oxidation rate depends not only on the overall molybdenum loading and dispersion, but also on the type of molybdenum oxide species prevalent at each surface density and on the domain size. As the molybdenum oxide oligomerisation increases, electron delocalisation becomes easier. This lowers the absorption edge energy and increases the reaction rate.
authors: Van 't Hoff Institute for Molecular Sciences, University of Amsterdam Science Park 904, 1090 GD Amsterdam, The Netherlands, ; e-mail:  n.r.shiju@uva.nl or g.rothenberg@uva.nl ; Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Carretera de Utrera Km 1 41013 Sevilla, Spain.
authors: Carlos
authors: C
authors: Caro
authors: K
authors: K
authors: Thirunavukkarasu
authors: M
authors: M
authors: Anilkumar
authors: N R
authors: NR
authors: Shiju
authors: Gadi
authors: G
authors: Rothenberg
keywords: UV-visible spectroscopy; acetaldehyde; heterogeneous catalysis; molybdenum oxide; sustainable chemistry
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