Poster Damien Debecker PhD thesis

<p>Poster sum up of the PhD thesis. Presented at the ceremony of the 2010 Umicore Scientific Award in Brussels.</p

High metathesis activity of dispersed molybdates in MoO3/SiO2-Al2O3 catalysts prepared via Flame Spray Pyrolysis

<p>Poster presented at the Europacat X Conference in Glasgow, Scotland<br>28 August – 2 September 2011</p

MoO3-based heterogeneous catalysts for the metathesis of propene

<p>The heterogeneous metathesis of light olefins is a crucial reaction for the regulation of olefins stocks at low energy cost. Molybdenum oxide dispersed at the surface of an inorganic support is a regarded cheap and robust heterogeneous metathesis catalyst. This thesis presents fundamental and applied approaches to the understanding of the active species and to the development of new efficient catalytic materials.</p> <p>A systematic investigation of MoO3/SiO2-(Al2O3) catalysts with variable support composition describes the crucial role of Al. Then, the best support composition is selected and a classical wet impregnation preparation method is inspected in details. For these catalysts, the genesis of active and inactive species during the preparation is described in link with the (limited) performances reached.</p> <p>Alternative MoO3 deposition modes are then explored. Firstly, the wet impregnation with alternative Mo precursors (use of oxalic acid additive or use of molybdenum oxide hydrates solutions) allows impeding the formation of inactive Mo species upon calcination and produces more active catalysts. Secondly, the direct thermal spreading of MoO3 onto the support is identified as an alternative straightforward route to obtain active metathesis catalysts.</p> <p>An innovative non-hydrolytic sol-gel method is then implemented to prepare MoO3-SiO2-Al2O3 mixed oxides. Upon optimization of homogeneity, texture and composition, these samples turn out to be very active metathesis catalysts because highly dispersed molybdate species are stabilized at their surface.</p

WO3-catalysts made by impregnation and aerosol process: towards higher propene yield

<p>Catalysts prepared by the original aerosol method have shown remarkable catalytic activity at relatively low reaction temperature. The decisive features for high activity in olefin metathesis under studied conditions are (i) good textural properties, (ii) strong interaction between the carrier and the WOx species. The latter is favoured in the case of silica-alumina where the acidity is well balanced and ensures that the WOx are not easy reducible. The aerosol process appears particularly suited to obtain these features.</p

A one step non-hydrolytic sol-gel route to mesoporous Re- and Mo-based mixed oxides for olefin metathesis

<p>The simplicity of NHSG makes it attractive: multi-step procedures, expensive precursors, or reactivity modifiers are not needed.</p> <p>Poster presented at the Europacat conference September 2, 2013, Lyon, France.</p