Catalytic hydrocarbon reactions over supported metals Page: 3 of 6
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
Laser Raman spectroscopy was used to characterize alumina-supported molybdenum and
tungsten oxides at loading ranging from 0.5 to 15 wt % Mo and 0.5 to 30 wt % W. The structure
of calcined Mo6+/Al2O3 and W6+/Al2O3 was governed by the point of zero surface charge of each
system, with the point of zero surface charge being dependent on metal loading. The structures
formed by the molybdenum and tungsten overlayers at the sample point of zero surface charge
were found to be analogous to the structures formed by molybdenum and tungsten oxyanions in
aqueous solution at a solution pH equal to the sample point of zero surface charge.
C. C. Williams and J. G. Ekerdt, The Absence of Molybdenum Precursor Effects for Methanol
Oxidation over Molybdenum Oxide Supported on Silica, J. Catal. 141 (1993) xxx.
The partial oxidation of methanol to formaldehyde and methyl formate has been studied at
low conversion over Mo/SiO2. Catalysts up to 1.1 wt% Mo were prepared from MoC15,
Mo2(ri3-C3H5)4, and (NH4)6Mo7O24-4H2O. Fumed silica (Cab-O-Sil EH-5), silica gel (Davison
952 and Rhone-Poulenc XOA-400) and Davison 952 silica, washed in acid to remove calcium,
were used as supports. Iron-doped Cab-O-Sil was also used. Over identical supports, the activity
and selectivity of methanol oxidation was similar for samples prepared from all precursors,
although some slight differences were observed. More significant differences were observed,
however, when the impurity levels were changed by acid-washing, iron-doping, and using
different types of silica. The results suggest that impurities on the silica support, rather than the
method of preparation or precursor, have a greater influence on methanol oxidation selectivity for
loadings less than 1.1 wt% Mo metal.
The abstracts are listed below for the manuscripts under review or in preparation.
C. C. Williams, J. G. Ekerdt, J.-M. Jehng, C.-K. Chen, F. D. Hardcastle, and I. E. Wachs,
Characterization of Molybdenum Oxide Magnesia Catalysts, Submitted to the Journal of Physical
Laser Raman spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse
reflectance spectroscopy, X-ray diffraction, and BET surface area analysis were used to
characterize magnesia supported Mo6+ prepared from Mo(i3-C3H5)4, Mo2(fl3-C3H5)4, MoCl5,
and (NH4)6Mo7O24.4H20. A well-dispersed and isolated molybdenum oxide species formed
from all precursors at weight loadings from 0.3 to 30% Mo. The results suggest a subsurface
molybdate species forms. Crystalline forms of molybdenum were also observed. MgMoO4 and
MoO3 formation occurred on samples containing 10 and 30% Mo, respectively, and was favored
by calcination at 700 C. CaMoO4 was formed at higher loadings on samples prepared by aqueous
impregnation with (NH4)6Mo7O24-4H20.
S. D. Kohler, M. F. Arendt, and J. G. Ekerdt, An XPS and IR Study of Silica-Supported
Chromium Oxide Photoreduction in CO, Manuscript in preparation.
The photoreduction of silica-supported chromium oxide in CO at 300 K was studied using
Fourier Transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS).
Chromium metal loadings of 0.5 to 2.0 wt % were investigated. The carbonyl stretching modes
were monitored as a function of reduction time using 12C160, 13C160, and 13C18. XPS was
used to characterize the oxidation state. The fully oxidized chromium, which was noncrystalline,
Here’s what’s next.
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Ekerdt, J.G. Catalytic hydrocarbon reactions over supported metals, report, March 29, 1993; United States. (https://digital.library.unt.edu/ark:/67531/metadc1207843/m1/3/: accessed March 21, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.