INVESTIGADORES
CADUS Luis Eduardo
artículos
Título:
CHARACTERIZATION OF Mo-Mn-O CATALYST FOR PROPANE OXIDATIVE DEHYDROGENATION
Autor/es:
LUIS EDUARDO CADUS; FERRETTI, O.
Revista:
APPLIED CATALYSIS A-GENERAL
Referencias:
Año: 2002 vol. 233 p. 239 - 253
ISSN:
0926-860X
Resumen:
Manganese oxide catalysts impregnated with molybdenum have been examined for the propane oxidative dehydrogenation.
These catalysts exhibit catalytic activity and yield to propane at temperatures as lowas 623 K. The catalysts were characterized
by SBET, XRD, Laser Raman, TPR, EPR and XPS. Independently of molybdenum loading, none of the impregnated catalysts
shows the patterns corresponding to molybdenum oxide by XRD. The reaction of molybdenum with manganese would
probably occur starting from OH centers as reacting nuclei and it continued from there. Thus, the OH of manganese oxide
surface would restrain the dispersion of the formed molybdate. However, the results of Raman spectroscopy analysis of
catalysts before and after the catalytic test indicate that the reaction test could be responsible for modifications in the surface
composition. Characterization before and after catalytic test corroborates the concept of the existence of a "dynamic feature"
in which the reaction of the adsorbed phase plays a key role in the surface reconstruction. EPR results as well as XPS ones
for catalysts after test have shown that independently of molybdenum loading, at a superficial level, all of them have similar
characteristics. Evidently, the reaction test promote a surface reconstruction. XPS data together with those obtained by XRD
which show that the greater the load, the more intense the MnMoO4 signal indicate that MnMoO4 accumulates in a definite
place being the XRD signal more intense by localized mass growth. These evidences and the consequent description of the
resulting surface architecture allow to understand the results of catalytic evaluation tests. © 2002 Elsevier Science B.V. All
rights reserved.SBET, XRD, Laser Raman, TPR, EPR and XPS. Independently of molybdenum loading, none of the impregnated catalysts
shows the patterns corresponding to molybdenum oxide by XRD. The reaction of molybdenum with manganese would
probably occur starting from OH centers as reacting nuclei and it continued from there. Thus, the OH of manganese oxide
surface would restrain the dispersion of the formed molybdate. However, the results of Raman spectroscopy analysis of
catalysts before and after the catalytic test indicate that the reaction test could be responsible for modifications in the surface
composition. Characterization before and after catalytic test corroborates the concept of the existence of a "dynamic feature"
in which the reaction of the adsorbed phase plays a key role in the surface reconstruction. EPR results as well as XPS ones
for catalysts after test have shown that independently of molybdenum loading, at a superficial level, all of them have similar
characteristics. Evidently, the reaction test promote a surface reconstruction. XPS data together with those obtained by XRD
which show that the greater the load, the more intense the MnMoO4 signal indicate that MnMoO4 accumulates in a definite
place being the XRD signal more intense by localized mass growth. These evidences and the consequent description of the
resulting surface architecture allow to understand the results of catalytic evaluation tests. © 2002 Elsevier Science B.V. All
rights reserved.4 signal indicate that MnMoO4 accumulates in a definite
place being the XRD signal more intense by localized mass growth. These evidences and the consequent description of the
resulting surface architecture allow to understand the results of catalytic evaluation tests. © 2002 Elsevier Science B.V. All
rights reserved.