Mesostructured CeO 2 as an Effective Catalyst for Styrene Synthesis by Oxidative Dehydrogenation of Ethylbenzene
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Mesostructured CeO2 as an Effective Catalyst for Styrene Synthesis by Oxidative Dehydrogenation of Ethylbenzene Jie Xu • Lun-Cun Wang • Yong-Mei Liu • Yong Cao • He-Yong He • Kang-Nian Fan
Received: 7 September 2009 / Accepted: 24 September 2009 / Published online: 14 October 2009 Ó Springer Science+Business Media, LLC 2009
Abstract A new type of mesostructured ceria material was synthesized via template-assisted precipitation method and tested for the oxidative dehydrogenation (ODH) of ethylbenzene to styrene by molecular oxygen. The effect of calcination temperature on the catalytic performances of the ceria catalysts has been investigated. Among the catalysts tested, the CeO2-450 sample derived by calcination at 450 °C exhibited the highest ethylbenzene conversion (34%) and styrene selectivity (87%). Comparing the reaction rates for ODH of ethylbenzene (ca. 6.1 mmol ST -1 g-1 at 450 °C) with the highly active nanostructured cat h carbon-based catalysts in the current literature confirmed the very high activity of these new materials. The superior catalytic performance of the CeO2-450 sample can be attributed to its high specific surface area and enhanced redox properties as revealed by H2-TPR measurements. Keywords Ceria Mesostructured Oxidative dehydrogenation (ODH) Ethylbenzene Styrene
1 Introduction Styrene (ST) is an important monomer extensively used in the chemical industry for the manufacture of polymers,
J. Xu L.-C. Wang Y.-M. Liu Y. Cao (&) H.-Y. He K.-N. Fan (&) Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 200433 Shanghai, People’s Republic of China e-mail: [email protected] K.-N. Fan e-mail: [email protected]
copolymers, and reinforced plastics [1]. Commercially, ST is mainly produced by means of the direct dehydrogenation (DH) of ethylbenzene (EB) at high reaction temperature (600–650 °C), with potassium-iron oxide as a catalyst [2, 3]. Due to its highly endothermic nature, this conventional route suffers from several disadvantages such as intensive energy consumption and rapid coking. Alternatively, the oxidative dehydrogenation (ODH) of EB has attracted considerable recent attention since it can be operated at lower temperatures and the EB conversion would not be equilibrium limited [2, 4–6]. A range of catalysts have been reported for this process in the recent literature including amorphous AlPO4 [1], V2O5/CeO2/ Al2O3 [2], CaO/SiO2 [7], MnO2/SiO2 [8], Mg(VO4)2-MgO [9]. In particular, promising results have been obtained when using onion like carbon (OLC) [5, 10] or carbon nanofibers (CNF) [11, 12] as the ODH catalyst. Nevertheless, the industrial application of the carbon-based catalysts has been till now prevented by their fine powder nature and intrinsically low resistance to combustion of the material [13]. In this context, there is a great incentive to develop new robust catalyst applicable for the ODH of EB. Ceria (CeO2) is a key redox component in the catalyst formulations for many industrially i
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