Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano
Ano de defesa: | 2010 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
Tipo de documento: | Dissertação |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de São Carlos
|
Programa de Pós-Graduação: |
Programa de Pós-Graduação em Engenharia Química - PPGEQ
|
Departamento: |
Não Informado pela instituição
|
País: |
BR
|
Palavras-chave em Português: | |
Palavras-chave em Inglês: | |
Área do conhecimento CNPq: | |
Link de acesso: | https://repositorio.ufscar.br/handle/ufscar/4035 |
Resumo: | Colloidal Nanoparticles of Platinum (Pt-NPs) were obtained by reducing hexacloroplatinic acid with ethylene glycol in the presence of polyvinylpyrrolidone (PVP) as protective agent of the particles. Two methods of synthesis were performed which differed by the ratio PVP / Pt used. The synthesis of nanoparticles was accompanied by measures in the UV-visible from of which it was possible to determine the end of the reaction. The Pt-NPs were characterized by Transmission Electron Microscopy (TEM) that determined the average diameter of particles (~ 2.0 nm). After the synthesis, the Pt-NPs were incorporated into the supports of alumina and alumina promoted with cerium and cerium-zirconium which were prepared by sol-gel method. Supporters with nanoparticles incorporated were then subjected to heat treatment have sought the formation of stable catalysts and without the presence of protective polymer, as this could affect the activity of the catalyst by covering the active sites. Through X-ray diffraction and TEM images it was possible to monitor the stability of samples after heat treatment and the samples that were synthesized with higher PVP were more stable. Measures of X-ray absorption fine structure (XAFS) spectroscopy in situ allowed the characterization of the samples in the reaction atmosphere. Through the analysis of extended X-ray absorption fine structure (EXAFS) was observed morphological changes in the particles caused by the increase in temperature showing that there is an increase in the number of atoms of low coordination when samples are heated which favors the reaction of steam reforming of methane. Through studies of X-ray absorption near edge structure (XANES) in the edges L2 and L3 of Pt was possible to monitor how the electron density of the catalysts varies in reaction conditions. Moreover, the catalysts were also tested catalysts. Measures of dispersion were obtained by the reaction of dehydrogenation of cyclohexane and catalysts made of alumina promoted with cerium and cerium-zirconium displayed less dispersion due to the coating caused by the support. The catalysts in which the particles were synthesized with a higher amount of PVP, because of its stability, were subjected to the reaction of steam reforming of methane and proved active. This reaction was used to calculate the value of the apparent activation energy. The catalysts containing promoters were more active than the catalyst only alumina thus showing the role of support in this reaction. Therefore, this system has proved very interesting to study the catalytic properties in reactions sensitive to the structure since the nanoparticles present are monodispersed and the catalyst is stable under reaction conditions allowing the study of structural and electronic properties. |
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Meira, Débora MottaBueno, José Maria Corrêahttp://lattes.cnpq.br/0157452280626031http://lattes.cnpq.br/16268000806004472016-06-02T19:56:37Z2010-05-042016-06-02T19:56:37Z2010-03-05MEIRA, Débora Motta. Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano. 2010. 107 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010.https://repositorio.ufscar.br/handle/ufscar/4035Colloidal Nanoparticles of Platinum (Pt-NPs) were obtained by reducing hexacloroplatinic acid with ethylene glycol in the presence of polyvinylpyrrolidone (PVP) as protective agent of the particles. Two methods of synthesis were performed which differed by the ratio PVP / Pt used. The synthesis of nanoparticles was accompanied by measures in the UV-visible from of which it was possible to determine the end of the reaction. The Pt-NPs were characterized by Transmission Electron Microscopy (TEM) that determined the average diameter of particles (~ 2.0 nm). After the synthesis, the Pt-NPs were incorporated into the supports of alumina and alumina promoted with cerium and cerium-zirconium which were prepared by sol-gel method. Supporters with nanoparticles incorporated were then subjected to heat treatment have sought the formation of stable catalysts and without the presence of protective polymer, as this could affect the activity of the catalyst by covering the active sites. Through X-ray diffraction and TEM images it was possible to monitor the stability of samples after heat treatment and the samples that were synthesized with higher PVP were more stable. Measures of X-ray absorption fine structure (XAFS) spectroscopy in situ allowed the characterization of the samples in the reaction atmosphere. Through the analysis of extended X-ray absorption fine structure (EXAFS) was observed morphological changes in the particles caused by the increase in temperature showing that there is an increase in the number of atoms of low coordination when samples are heated which favors the reaction of steam reforming of methane. Through studies of X-ray absorption near edge structure (XANES) in the edges L2 and L3 of Pt was possible to monitor how the electron density of the catalysts varies in reaction conditions. Moreover, the catalysts were also tested catalysts. Measures of dispersion were obtained by the reaction of dehydrogenation of cyclohexane and catalysts made of alumina promoted with cerium and cerium-zirconium displayed less dispersion due to the coating caused by the support. The catalysts in which the particles were synthesized with a higher amount of PVP, because of its stability, were subjected to the reaction of steam reforming of methane and proved active. This reaction was used to calculate the value of the apparent activation energy. The catalysts containing promoters were more active than the catalyst only alumina thus showing the role of support in this reaction. Therefore, this system has proved very interesting to study the catalytic properties in reactions sensitive to the structure since the nanoparticles present are monodispersed and the catalyst is stable under reaction conditions allowing the study of structural and electronic properties.Nanopartículas coloidais de platina (NPs-Pt) foram obtidas por meio da redução do ácido hexacloroplatínico por etilenoglicol na presença de polivinilpirrolidona (PVP) como agente protetor das partículas. Dois métodos de síntese foram realizados os quais se diferiram pela razão PVP/Pt empregada. As sínteses das NPs-Pt foram acompanhadas por medidas no UVvisível através das quais foi possível determinar o fim da reação. As NPs-Pt foram caracterizadas por microscopia eletrônica de transmissão (TEM) que determinou o diâmetro médio das partículas (~2,0 nm). Após a síntese as NPs-Pt foram incorporadas à suportes de alumina e alumina promovida com cério e cério-zircônio os quais foram preparados pelo método sol-gel. Os suportes com as nanopartículas incorporadas foram então submetidos a tratamentos térmicos com o objetivo de levar à formação de catalisadores estáveis e sem a presença do polímero protetor. Através de difração de raios X e imagens de TEM foi possível acompanhar a estabilidade das amostras após o tratamento térmico tendo sido as amostras sintetizadas com maior quantidade de PVP mais estáveis. Medidas de espectroscopia de estrutura fina de absorção de raios X (XAFS) in situ permitiram a caracterização da amostra em atmosfera de reação. Através da análise da região estendida após a borda, EXAFS, foi possível observar mudanças morfológicas nas partículas ocasionadas pelo aumento da temperatura mostrando que há um aumento no número de átomos de baixa coordenação quando as amostras são aquecidas o que favorece a reação de reforma a vapor do metano. Através de estudos da região próxima às bordas L2 e L3 da Pt (XANES) foi possível acompanhar como a densidade eletrônica dos catalisadores variou em condições de reação. Por fim, os catalisadores foram submetidos a ensaios catalíticos. Medidas de dispersão foram obtidas através da reação de desidrogenação do ciclohexano tendo os catalisadores preparados com alumina promovida com Ce e Ce-Zr apresentado uma menor dispersão devido ao recobrimento ocasionado pelo suporte. Devido à sua estabilidade, os catalisadores obtidos a partir das nanopartículas sintetizadas com maior razão PVP/Pt, foram submetidos à reação de reforma a vapor do metano e se mostraram ativos. Essa reação foi utilizada para calcular o valor da energia de ativação aparente. Os catalisadores contendo promotores foram mais ativos, mostrando assim o papel do suporte nessa reação. Portanto, essa abordagem se mostrou bastante interessante para o estudo das propriedades catalíticas em reações sensíveis à estrutura devido à estreita distribuição de tamanhos das nanopartículas e sua estabilidade em condições de reação permitindo o estudo detalhado de suas propriedades estruturais e eletrônicasUniversidade Federal de Minas Geraisapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Engenharia Química - PPGEQUFSCarBRCatálise heterogêneaNanopartículasXAS in situPlatinaReforma a vapor do metanoNanoparticlesPlatinumXAFS in situSteam reforming of methaneENGENHARIAS::ENGENHARIA QUIMICASíntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metanoinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL2931.pdfapplication/pdf6814472https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/4035/1/2931.pdf46c69cfcaa07e8f2ab4e1d803b03916aMD51THUMBNAIL2931.pdf.jpg2931.pdf.jpgIM Thumbnailimage/jpeg7566https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/4035/2/2931.pdf.jpga786e64757fdf4550d2b2e37643040f5MD52ufscar/40352019-09-11 02:30:04.767oai:repositorio.ufscar.br:ufscar/4035Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-05-25T12:48:06.679981Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
title |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
spellingShingle |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano Meira, Débora Motta Catálise heterogênea Nanopartículas XAS in situ Platina Reforma a vapor do metano Nanoparticles Platinum XAFS in situ Steam reforming of methane ENGENHARIAS::ENGENHARIA QUIMICA |
title_short |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
title_full |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
title_fullStr |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
title_full_unstemmed |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
title_sort |
Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano |
author |
Meira, Débora Motta |
author_facet |
Meira, Débora Motta |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/1626800080600447 |
dc.contributor.author.fl_str_mv |
Meira, Débora Motta |
dc.contributor.advisor1.fl_str_mv |
Bueno, José Maria Corrêa |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/0157452280626031 |
contributor_str_mv |
Bueno, José Maria Corrêa |
dc.subject.por.fl_str_mv |
Catálise heterogênea Nanopartículas XAS in situ Platina Reforma a vapor do metano |
topic |
Catálise heterogênea Nanopartículas XAS in situ Platina Reforma a vapor do metano Nanoparticles Platinum XAFS in situ Steam reforming of methane ENGENHARIAS::ENGENHARIA QUIMICA |
dc.subject.eng.fl_str_mv |
Nanoparticles Platinum XAFS in situ Steam reforming of methane |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA QUIMICA |
description |
Colloidal Nanoparticles of Platinum (Pt-NPs) were obtained by reducing hexacloroplatinic acid with ethylene glycol in the presence of polyvinylpyrrolidone (PVP) as protective agent of the particles. Two methods of synthesis were performed which differed by the ratio PVP / Pt used. The synthesis of nanoparticles was accompanied by measures in the UV-visible from of which it was possible to determine the end of the reaction. The Pt-NPs were characterized by Transmission Electron Microscopy (TEM) that determined the average diameter of particles (~ 2.0 nm). After the synthesis, the Pt-NPs were incorporated into the supports of alumina and alumina promoted with cerium and cerium-zirconium which were prepared by sol-gel method. Supporters with nanoparticles incorporated were then subjected to heat treatment have sought the formation of stable catalysts and without the presence of protective polymer, as this could affect the activity of the catalyst by covering the active sites. Through X-ray diffraction and TEM images it was possible to monitor the stability of samples after heat treatment and the samples that were synthesized with higher PVP were more stable. Measures of X-ray absorption fine structure (XAFS) spectroscopy in situ allowed the characterization of the samples in the reaction atmosphere. Through the analysis of extended X-ray absorption fine structure (EXAFS) was observed morphological changes in the particles caused by the increase in temperature showing that there is an increase in the number of atoms of low coordination when samples are heated which favors the reaction of steam reforming of methane. Through studies of X-ray absorption near edge structure (XANES) in the edges L2 and L3 of Pt was possible to monitor how the electron density of the catalysts varies in reaction conditions. Moreover, the catalysts were also tested catalysts. Measures of dispersion were obtained by the reaction of dehydrogenation of cyclohexane and catalysts made of alumina promoted with cerium and cerium-zirconium displayed less dispersion due to the coating caused by the support. The catalysts in which the particles were synthesized with a higher amount of PVP, because of its stability, were subjected to the reaction of steam reforming of methane and proved active. This reaction was used to calculate the value of the apparent activation energy. The catalysts containing promoters were more active than the catalyst only alumina thus showing the role of support in this reaction. Therefore, this system has proved very interesting to study the catalytic properties in reactions sensitive to the structure since the nanoparticles present are monodispersed and the catalyst is stable under reaction conditions allowing the study of structural and electronic properties. |
publishDate |
2010 |
dc.date.available.fl_str_mv |
2010-05-04 2016-06-02T19:56:37Z |
dc.date.issued.fl_str_mv |
2010-03-05 |
dc.date.accessioned.fl_str_mv |
2016-06-02T19:56:37Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
MEIRA, Débora Motta. Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano. 2010. 107 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/4035 |
identifier_str_mv |
MEIRA, Débora Motta. Síntese e caracterização de nanocatalisadores de platina suportados aplicados à reação de reforma do metano. 2010. 107 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010. |
url |
https://repositorio.ufscar.br/handle/ufscar/4035 |
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openAccess |
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application/pdf |
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Universidade Federal de São Carlos |
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Programa de Pós-Graduação em Engenharia Química - PPGEQ |
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UFSCar |
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BR |
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Universidade Federal de São Carlos |
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