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Title: High reactivity of nanosized niobium oxide cluster cations in methane activation: A comparison with vanadium oxides

The reactions between methane and niobium oxide cluster cations were studied and compared to those employing vanadium oxides. Hydrogen atom abstraction (HAA) reactions were identified over stoichiometric (Nb{sub 2}O{sub 5}){sub N}{sup +} clusters for N as large as 14 with a time-of-flight mass spectrometer. The reactivity of (Nb{sub 2}O{sub 5}){sub N}{sup +} clusters decreases as the N increases, and it is higher than that of (V {sub 2}O{sub 5}){sub N}{sup +} for N ≥ 4. Theoretical studies were conducted on (Nb{sub 2}O{sub 5}){sub N}{sup +} (N = 2–6) by density functional calculations. HAA reactions on these clusters are all favorable thermodynamically and kinetically. The difference of the reactivity with respect to the cluster size and metal type (Nb vs V) was attributed to thermodynamics, kinetics, the electron capture ability, and the distribution of the unpaired spin density. Nanosized Nb oxide clusters show higher HAA reactivity than V oxides, indicating that niobia may serve as promising catalysts for practical methane conversion.
Authors:
;  [1] ; ; ; ;  [2]
  1. Department of Mathematics and Physics, North China Electric Power University, Beinong Road 2, Huilongguan, Beijing 102206 (China)
  2. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)
Publication Date:
OSTI Identifier:
22489646
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ATOMS; CATALYSTS; CATIONS; COMPARATIVE EVALUATIONS; DENSITY; DENSITY FUNCTIONAL METHOD; ELECTRON CAPTURE; HYDROGEN; KINETICS; METALS; METHANE; NANOSTRUCTURES; NIOBATES; NIOBIUM OXIDES; REACTIVITY; SPIN; THERMODYNAMICS; TIME-OF-FLIGHT MASS SPECTROMETERS; VANADIUM OXIDES