Preparation of super-microporous WO3-SiO2 olefin metathesis catalysts by the aerosol-assisted sol-gel process

Maksasithorn, Surasa [UCL] Praserthdam, Piyasan [Chulalongkorn University, Bangkok, Thailand ] Suriye, Kongkiat [Chulalongkorn University, Bangkok, Thailand ] Debecker, Damien P. [UCL]

Highly effective tungsten oxide-based catalysts are prepared by a one-pot aerosol-assisted sol–gel method. Their catalytic performances are evaluated in the cross-metathesis of ethene and trans-2-butene for the production of propene. The catalysts are comprehensively characterized by N2-physisorption, ICP-OES, SEM, TEM, XRD, UV–Vis spectroscopy, NH3-TPD, NH3-chemisorption, XPS, and TPR. Benefiting from the advantage of the aerosol process, the new WO3–SiO2 catalysts display outstanding textural properties, with a high specific surface area (500–600 m2 g−1) solely generated by calibrated super-micropores of about 2 nm. The catalyst particles are perfectly spherical in shape and feature high W dispersion and appropriate reducibility and surface acidity. As compared to reference catalysts prepared by traditional impregnation on a commercial silica support, the aerosol catalysts exhibit higher metathesis activity and shorter induction period. Conversion and selectivity are shown to increase with WO3 loading (up to 15 wt.%). Calcination temperature (450–850 °C) is identified as an essential parameter impacting significantly the texture, the surface acidity, and therefore also the catalytic activity.