Título: | PROPERTIES OF MO-SNO2 CATALYSTS AND THE EFECT OF SODIUM ADDITION | ||||||||||||||||||||||||||||||||||||||||
Autor: |
ISAQUE CARDOSO DA SILVA |
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Colaborador(es): |
SILVANA BRAUN - Orientador LUCIA GORENSTIN APPEL - Coorientador |
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Catalogação: | 10/MAR/2005 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||||||||||||||||||||||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=6045&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=6045&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.6045 | ||||||||||||||||||||||||||||||||||||||||
Resumo: | |||||||||||||||||||||||||||||||||||||||||
Mo-SnO2 catalysts were prepared by SnO2.xH2O precipitation
with ammonium
heptamolybdate solution. Two Mo amounts were used: 5,5 and
14,5 percent (wt);
Afterwards, these samples were impregnated with 1 percent Na
(wt). These solids
were characterized by nitrogen adsorption, UV-visible
diffuse reflectance
spectroscopy, temperature programmed reduction, X-ray
diffraction, infrared
spectroscopy of adsorbed pyridine and methanol. It was
observed that the Na
addition decreases the surface area of the Mo-SnO2 solids,
caused by
elimination of the micropores and the large pores of
polymolybdates. It was
also verified that Na promotes the agglomeration of Mo
species, i.e. the amount
of Mo dispersed species decreases and the polymolybdate one
increases.
Sodium also changes the solid acid properties: for the low
Mo amount it was
observed that Na promoted the formation of weak Lewis acid
sites and the
elimination of Brönsted sites; on the other hand for the
high Mo amount, both
Brönsted and weak Lewis acid sites content increased when
Na was added.
These results showed that sodium changed the texture, the
Mo species and the
acid properties of Mo-SnO2 catalysts.
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