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Title: Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane

Abstract

A vanadium oxide-carbon nanotube composite was prepared by solution-based hydrolysis of NH{sub 4}VO{sub 3} in the presence of carbon nanotubes. The carbon nanotubes induce the nucleation of the 1D vanadium oxide nanostructures, with the nuclei growing into long freestanding nanorods. The vanadium oxide nanorods with the lengths up to 20 {mu}m and the widths of 5-15 nm exhibit a well-ordered crystalline structure. Catalytic tests show that the composite with nanostructured vanadium oxide is active for the partial oxidation of n-butane to maleic anhydride at 300 deg. C.

Authors:
 [1];  [1];  [1];  [2];  [1]
  1. Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany)
  2. Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany). E-mail: dangsheng@fhi-berlin.mpg.de
Publication Date:
OSTI Identifier:
21000596
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 42; Journal Issue: 2; Other Information: DOI: 10.1016/j.materresbull.2006.05.026; PII: S0025-5408(06)00235-2; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANHYDRIDES; BUTANE; CARBON; CATALYSTS; ELECTRON MICROSCOPY; HYDROLYSIS; NANOTUBES; NUCLEATION; OXIDATION; VANADIUM OXIDES; X-RAY DIFFRACTION

Citation Formats

Chen Xiaowei, Zhu Zhenping, Haevecker, Michael, Su Dangsheng, and Schloegl, Robert. Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane. United States: N. p., 2007. Web. doi:10.1016/j.materresbull.2006.05.026.
Chen Xiaowei, Zhu Zhenping, Haevecker, Michael, Su Dangsheng, & Schloegl, Robert. Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane. United States. doi:10.1016/j.materresbull.2006.05.026.
Chen Xiaowei, Zhu Zhenping, Haevecker, Michael, Su Dangsheng, and Schloegl, Robert. Thu . "Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane". United States. doi:10.1016/j.materresbull.2006.05.026.
@article{osti_21000596,
title = {Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane},
author = {Chen Xiaowei and Zhu Zhenping and Haevecker, Michael and Su Dangsheng and Schloegl, Robert},
abstractNote = {A vanadium oxide-carbon nanotube composite was prepared by solution-based hydrolysis of NH{sub 4}VO{sub 3} in the presence of carbon nanotubes. The carbon nanotubes induce the nucleation of the 1D vanadium oxide nanostructures, with the nuclei growing into long freestanding nanorods. The vanadium oxide nanorods with the lengths up to 20 {mu}m and the widths of 5-15 nm exhibit a well-ordered crystalline structure. Catalytic tests show that the composite with nanostructured vanadium oxide is active for the partial oxidation of n-butane to maleic anhydride at 300 deg. C.},
doi = {10.1016/j.materresbull.2006.05.026},
journal = {Materials Research Bulletin},
number = 2,
volume = 42,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • The catalytic activities for n-butane conversion to maleic anhydride of two series of vanadium-phosphorus oxide catalysts with phosphorus:vanadium ratios in the range 0.94 to 1.10 and calcined at 773 or 923 K were compared before and after reduction by hydrogen. In almost all cases studied, reduction gave rise to increased conversion, and for catalysts with low phosphorus:vanadium ratios increased selectivity was also noted. When n-butane was contacted with these catalysts in the absence of gas phase oxygen, maleic anhydride and total oxidation products continued to be formed until changes in average oxidation state of vanadium of up to -1.5 weremore » recorded. From considerations of the dynamic state of the catalysts during catalysis, it was concluded that a morphology consisting of oxidized surface layers on a reduced core favors high activities and selectivities for this process.« less
  • The values of the kinetic isotope effect have been determined in reactions where n-butane is converted to partial (maleic anhydride) and complete oxidation products on a vanadium-phosphorus oxide catalyst when hydrogen is replaced by deuterium in different positions of the n-butane molecule. The absence of intra- and intermolecular H-D exchange in butane under conditions of its catalytic oxidation has been established. On the basis of the observed effects it has been concluded that the interaction of n-butane with the surface of the catalyst is irreversible under the conditions of catalysis and that the rate-limiting stage due to cleavage of themore » C-H bond in a methylene group of butane is common to reactions of partial and complete oxidation of butane.« less
  • This study examines the role of zirconium as a promoter in the selective oxidation of n-butane to maleic anhydride on a vanadium-phosphorus oxide catalyst. Reaction studies show that low levels of zirconium (Zr/V = 0.03) decrease the temperature of maximum yield relative to the unpromoted catalyst. Higher levels of zirconium (Zr/V = 0.13) result in lower yields. [sup 16]O[sub 2]-[sup 18]O[sub 2] exchange measurements show no evidence for oxygen exchange between the gas phase and the bulk lattice at 400[degrees]C, in agreement with other studies. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements are combined with the reaction studiesmore » to indicate a probable structural role for zirconium as a promoter. 19 refs., 9 figs., 3 tabs.« less
  • The reaction kinetics of the oxidative dehydrogenation (ODH) of n-butane over vanadia supported on a heat-treated Mg/Al hydrotalcite (37.3 wt % of V{sub 2}O{sub 5}) was investigated by both linear and nonlinear regression techniques. A reaction network including the formation of butenes (1-, 2-cis-, and 2-trans-butene), butadiene, and carbon oxides by parallel and consecutive reactions, at low and high n-butane conversions, has been proposed. Langmuir-Hinshelwood (LH) models can be used as suitable models which allows reproduction of the global kinetic behavior, although differences between oxydehydrogenation and deep oxidation reactions have been observed. Thus, the formation of oxydehydrogenation products can bemore » described by a LH equation considering a dissociative adsorption of oxygen while the formation of carbon oxides is described by a LH equation with a nondissociative adsorption of oxygen. Two different mechanisms operate on the catalyst: (i) a redox mechanism responsible of the formation of olefins and diolefins and associated to vanadium species, which is initiated by a hydrogen abstraction; (ii) a radical mechanism responsible of the formation of carbon oxides from n-butane and butenes and associated to vanadium-free sites of the support. On the other hand, the selectivity to oxydehydrogenation products increases with the reaction temperature. This catalytic performance can be explained taking into account the low reducibility of V{sup 5+}-sites and the higher apparent activation energies of the oxydehydrogenation reactions with respect to deep oxidation reactions.« less
  • The interaction of n-butane with a ((VO){sub 2}P{sub 2}O{sub 7}) catalyst has been investigated by temperature-programmed desorption and anaerobic temperature-programmed reaction. n-Butane has been shown to adsorb on the (VO){sub 2}P{sub 2}O{sub 7} to as a butyl-hydroxyl pair. When adsorption is carried out at 223 K, upon temperature programming some of the butyl-hydroxyl species recombine resulting in butane desorption at 260 K. However, when adsorption is carried out at 423 K, the hydroxyl species of the butyl-hydroxyl pair migrate away from the butyl species during the adsorption, forming water which is detected in the gas phase. Butane therefore is notmore » observed to desorb at 260 K after the authors lowered the temperature to 223 K under the butane/helium from the adsorption temperature of 423 K prior to temperature programming from that temperature to 1100 K under a helium stream. Anaerobic temperature-programmed oxidation of n-butane produces butene and butadiene at a peak maximum temperature of 1000 K; this is exactly the temperature at which, upon temperature programming, oxygen evolves from the lattice and desorbs as O{sub 2}. This, and the fact that the amount of oxygen desorbing from the (VO){sub 2}P{sub 2}O{sub 7} at {approximately}1000 K is the same as that required for the oxidation of the n-butane to butene and butadiene, strongly suggests (1) that lattice oxygen as it emerges at the surface is the selective oxidant and (2) that its appearance at the surface is the rate-determining step in the selective oxidation of n-butane. The surface of the (VO){sub 2}P{sub 2}O{sub 7} catalyst on which this selective oxidation takes place has had approximately two monolayers of oxygen removed from it by unselective oxidation of the n-butane to CO, CO{sub 2}, and H{sub 2}O between 550 and 950 K and has had approximately one monolayer of carbon deposited on it at {approximately}1000 K. It is apparent, therefore, that the original crystallography of the (VO){sub 2}P{sub 2}O{sub 7} catalyst will not exist during this selective oxidation and that theories that relate selectivity in partial oxidation to the (100) face of the (VO){sub 2}P{sub 2}O{sub 7} catalyst cannot apply in this case.« less