Vanadium Oxide Based Nanostructured Materials for Catalytic Oxidative Dehydrogenation of Propane: Effect of Heterometall
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Vanadium Oxide Based Nanostructured Materials for Catalytic Oxidative Dehydrogenation of Propane: Effect of Heterometallic Centers on the Catalyst Performance M. Ishaque Khan • Sangita Deb • Kadir Aydemir • Abdulrahman A. Alwarthan • Soma Chattopadhyay Jeffrey T. Miller • Christopher L. Marshall
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Received: 30 September 2009 / Accepted: 11 January 2010 / Published online: 2 February 2010 Ó Springer Science+Business Media, LLC 2010
Abstract Catalytic properties of a series of new class of catalysts materials—[Co3(H2O)12V18O42 (XO4)].24H2O (VNM-Co), [Fe3(H2O)12V18O42(XO4)].24H2O (VNM-Fe) (X = V, S) and [H6Mn3(H2O)12V18O42(VO4)].30H2O for the oxidative dehydrogenation of propane is studied. The open-framework nanostructures in these novel materials consist of three-dimensional arrays of {V18O42(XO4)} (X = V, S) clusters interconnected by {–O–M–O–} (M = Mn, Fe, Co) linkers. The effect of change in the heterometallic center M (M = Mn, Co, Fe) of the linkers on the catalyst performance was studied. The catalyst material with Co in the linker showed the best performance in terms of propane conversion and selectivity at 350 °C. The material containing Fe was most active but least selective and Mn containing catalyst was least active. The catalysts were characterized by Temperature Programmed Reduction (TPR), BET surface area measurement, Diffuse Reflectance Infrared Fourier Transform Spectroscopy, and X-ray Absorption Spectroscopy. TPR results show that all three catalysts are easily reducible and therefore are active
Electronic supplementary material The online version of this article (doi:10.1007/s10562-010-0275-6) contains supplementary material, which is available to authorized users. M. I. Khan (&) S. Deb K. Aydemir S. Chattopadhyay Department of Biological, Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA e-mail: [email protected] A. A. Alwarthan Chemistry Department, Science College, King Saud University, Riyadh 11451, Saudi Arabia J. T. Miller C. L. Marshall Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439, USA
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at relatively low temperature. In situ X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS) studies revealed that the oxidation state of Co(II) remained unchanged up to 425 °C (even after pretreatment). The reduction of Co(II) into metallic form starts at 425 °C and this process is completed at 600 °C. Keywords Vanadium oxides Oxidative dehydrogenation Heterogeneous catalysis Propylene X-ray absorption spectroscopy EXAFS
1 Introduction Oxidative dehydrogenation (ODH) of propane to propylene is receiving increased attention compared to the classical dehydrogenation processes due to the major drawbacks associated with the classical processes and increasing global demand for propylene [1]. ODH, which requires the presence of an oxidant, converts the hydrogen eliminated from propane to water thereby transforming a highly endothermic reaction into an
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