Thumbnail
Access Restriction
Open

Author Deng, H. T. ♦ Kerns, K. P. ♦ Castleman, A. W. (Jr.)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CHEMISTRY ♦ PHYSICS ♦ NIOBIUM OXIDES ♦ MASS SPECTRA ♦ OXYGEN ♦ ACTIVATION ENERGY ♦ SOLID CLUSTERS ♦ IONS ♦ DISSOCIATION ♦ COLLISIONS ♦ CATALYSTS ♦ PLASMA ♦ IONIZATION POTENTIAL
Abstract Niobium oxide cluster ions are produced by a laser-induced plasma source. The cluster distribution, collision-induced dissociation (CID), and cluster reactivities are studied using a triple-quadrupole mass spectrometer. CID experiments on the cluster ions Nb{sub 3}O{sub 7-9}{sup +}, Nb{sub 4}O{sub 9-11}{sup +}, and Nb{sub 5}O{sub 12}{sup +} reveal that their building blocks are Nb{sub 2}O{sub 5}, NbO{sub 2}{sup +}, NbO{sub 3}, Nb{sub 3}O{sub 7}{sup +}, O, and O{sub 2}, whereby the cluster stoichiometry is assigned to have the general form (NbO{sub 3}){sub m}(NbO{sub 2}){sub n}(O){sub 0-4}{sup +}. The trends in the ionization potentials of these species are estimated in terms of the CID fragments produced. Nb{sub 3}O{sub 8-9}{sup +} and Nb{sub 4}O{sub 11}{sup +} cluster ions evidently form via the adsorption of one oxygen atom or molecule onto the cluster surface. Nb{sub 3}O{sub 7}{sup +}, Nb{sub 4}O{sub 9}{sup +}, and Nb{sub 5}O{sub 12}{sup +} have strong reactivities to abstract an oxygen atom from oxygen-containing molecules and adsorb small hydrocarbons at near thermal energies. In particular, the reactivity of the oxygen atom or molecule in the oxide clusters Nb{sub 3}O{sub 8-9}{sup +} and Nb{sub 4}O{sub 11}{sup +} is consistent with our suggestions that it has a radical oxygen character. 37 refs., 8 figs., 1 tab.
ISSN 00223654
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-08-01
Publisher Place United States
Journal Journal of Physical Chemistry
Volume Number 100
Issue Number 32


Open content in new tab

   Open content in new tab