Título: | SYNTHESIS AND CHARACTERIZATION OF CU-BASED CATALYSTS USED IN THE STEAM REFORMING OF METHANOL | ||||||||||||||||||||||||||||||||||||
Autor: |
SABRINA GUIMARAES SANCHES |
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Colaborador(es): |
MARIA ISABEL PAIS DA SILVA - Orientador JHONNY OSWALDO HUERTAS FLORES - Coorientador |
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Catalogação: | 10/FEV/2010 | 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=15152&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=15152&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.15152 | ||||||||||||||||||||||||||||||||||||
Resumo: | |||||||||||||||||||||||||||||||||||||
Since years 70 with the petroleum crisis the search for alternative energy has
being developed. Moreover, obtaining clean energy is also an environmental goal.
The hydrogen production by steam reforming of methanol is an important clean
energy alternative source that can be used in fuel cells. In this work catalysts
based in Cu were prepared by different methods: coprecipitation, sequential
precipitation and homogeneous precipitation. Some variations in these methods
also were tested as the reagents addition order and aging time. Zirconium and
yttrium were used as promoters in different amounts. The catalysts were
characterized by a variety of techniques, including Inductively Coupled Plasma-
Optical Emission Spectroscopy (ICP-OES), Atomic Absorption Spectroscopy
(AAS), N2 adsorption surface area analysis, X-Ray Diffraction (XRD), Thermogravimetric
Analysis (TGA), Transmission Electron Microscopy (TEM),
Temperature Programmed Desorption of H2 (H2-TPD), N2O oxidation and
infrared spectroscopy of methanol adsorption. The preparation methods did not
influence the precursor phase formation. The aurichalcite was the main phase
found in the catalysts as prepared. In the case of calcined catalysts were found the
CuO and ZnO phases. Yttrium based catalysts prepared by co-precipitation
method showed no crystalline precursor phases and smaller surface areas.
Zirconium modified the catalyst crystalline structure increasing surface area and
the metallic copper area when prepared by homogeneous precipitation. Two
decomposition steps were found in the majority of catalysts and were attributed to
dehydroxylation and decarbonation of precursor phases. H2-TPD profiles showed
three or four desorption peaks that were attributed to Cu metallic sites of different
sizes at the samples surface. The metal area values obtained by H2-TPD and N2O oxidation techniques were not coincident. This fact indicated that this kind of
determination is only to observe tendences. The preparation methods and
promoter type influenced the catalysts morphologies. Catalyst prepared by coprecipitation
method showed regular particles. When others methods were used
particles with needle forms were found. They were origined by the remained
precursor after the sample calcination. Infrared results showed bands attributed to
formiates and metoxy ions adsorbed on oxide copper. These ions would be the
intermediate species in the steam reforming of methanol confirming the water
influence in the Cu metallic species oxidation. These oxided species seem to be
the responsibles by the hydrogen formation.
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