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Electron microscopy of some molybdenum oxide phases after use as catalysts in oxidative ammonolysis and ammoxidation of toluene

Hansen, Staffan LU and Andersson, Arne LU (1988) In Journal of Solid State Chemistry 75(2). p.225-243
Abstract
Five molybdenum oxide samples, subjected to conditions of oxidative ammonolysis and ammoxidation of toluene at 450 and 460°C, respectively, have been characterized using X-ray diffraction, scanning and transmission electron microscopy, and specific surface area measurements. In oxidative ammonolysis, the relatively large, freshly prepared MoO3 crystals are reduced to smaller MoO2 crystals with a crystallite size of 5–30 nm. This process gives a perfectly pseudomorphous product with pores less than 5 nm. The specific surface area increases from <0.1 m2/g to almost 40 m2/g. In subsequent ammoxidation, MoO2 transforms first into orthorhombic Mo4O11 and finally into MoO3. The crystals of Mo4O11 are about 1 μm in diameter, and their... (More)
Five molybdenum oxide samples, subjected to conditions of oxidative ammonolysis and ammoxidation of toluene at 450 and 460°C, respectively, have been characterized using X-ray diffraction, scanning and transmission electron microscopy, and specific surface area measurements. In oxidative ammonolysis, the relatively large, freshly prepared MoO3 crystals are reduced to smaller MoO2 crystals with a crystallite size of 5–30 nm. This process gives a perfectly pseudomorphous product with pores less than 5 nm. The specific surface area increases from <0.1 m2/g to almost 40 m2/g. In subsequent ammoxidation, MoO2 transforms first into orthorhombic Mo4O11 and finally into MoO3. The crystals of Mo4O11 are about 1 μm in diameter, and their formation leads to a decrease of specific surface area. The original MoO3 morphology is retained even after the sequence of transformation as follows: MoO3 → MoO2 → Mo4O11 (→MoO3). In some cases, the new generation of MoO3 crystals grows parallel to the original MoO3 crystals. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Solid State Chemistry
volume
75
issue
2
pages
225 - 243
publisher
Elsevier
external identifiers
  • wos:A1988P749200002
  • scopus:0024064167
ISSN
0022-4596
DOI
10.1016/0022-4596(88)90162-4
language
English
LU publication?
yes
id
90dc622f-435b-48a8-b106-3008ba1b7a25 (old id 3914639)
date added to LUP
2013-07-01 13:14:51
date last changed
2017-08-27 05:11:31
@article{90dc622f-435b-48a8-b106-3008ba1b7a25,
  abstract     = {Five molybdenum oxide samples, subjected to conditions of oxidative ammonolysis and ammoxidation of toluene at 450 and 460°C, respectively, have been characterized using X-ray diffraction, scanning and transmission electron microscopy, and specific surface area measurements. In oxidative ammonolysis, the relatively large, freshly prepared MoO3 crystals are reduced to smaller MoO2 crystals with a crystallite size of 5–30 nm. This process gives a perfectly pseudomorphous product with pores less than 5 nm. The specific surface area increases from &lt;0.1 m2/g to almost 40 m2/g. In subsequent ammoxidation, MoO2 transforms first into orthorhombic Mo4O11 and finally into MoO3. The crystals of Mo4O11 are about 1 μm in diameter, and their formation leads to a decrease of specific surface area. The original MoO3 morphology is retained even after the sequence of transformation as follows: MoO3 → MoO2 → Mo4O11 (→MoO3). In some cases, the new generation of MoO3 crystals grows parallel to the original MoO3 crystals.},
  author       = {Hansen, Staffan and Andersson, Arne},
  issn         = {0022-4596},
  language     = {eng},
  number       = {2},
  pages        = {225--243},
  publisher    = {Elsevier},
  series       = {Journal of Solid State Chemistry},
  title        = {Electron microscopy of some molybdenum oxide phases after use as catalysts in oxidative ammonolysis and ammoxidation of toluene},
  url          = {http://dx.doi.org/10.1016/0022-4596(88)90162-4},
  volume       = {75},
  year         = {1988},
}