Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano
Autor(a) principal: | |
---|---|
Data de Publicação: | 2005 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/4170 |
Resumo: | 15%Ni/Al2O3 catalysts was obtained by impregnation with Ni(NO3)2 aqueous solution and promoted with Au and Ag. The Au was successively impregnated with aqueous solution of [Au(NH3)4](NO3)3. The Ag was coimpregnated with aqueous solution of AgNO3- Ni(NO3)2. The effect of Ag and Au on the catalytic behavior of Ni/Al2O3 catalysts in the reaction of steam reforming of CH4 was elucidate. The catalysts were characterized by temperatureprogrammed reduction (TPR), temperature-programmed dessorption of H2 (TPDH2) and Fourier transform infrared spectroscopy (FTIR) of CO adsorption. TPR results indicated that NiO is in weak interaction with support and the temperature reduction of NiO is independent of Ag and Au presence. FTIR data of CO adsorbed showed that Ag and Au suppress the CO adsorption in poli-coordination relative to the linear CO. Ag or Au on the Ni surface presents a determinant role in the block of graphitic carbon formation in the reaction of steam reforming of CH4. The fit of Arrhenius equation to rate of the total reaction showed a compensation effect between the apparent activation energy (Ea ap) and logarithmic of prefactor (k0). The linear increase of Ea ap with rise of lnk0 is observed increasing Ag and Au loading, which is followed by decreasing of the catalytic activity. Theses results suggest that the CHx intermediates, formed in the determinant stage of global velocity, show low interaction of with surface of Ni. The increase of the resistance for graphite formation by presence of Ag or Au is mainly attributed to the block of highly uncoordinated Ni atoms, which are higher activity to activation of CH4 and act as nucleation site for graphite formation. |
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Rocha, Kleper de OliveiraBueno, José Maria Corrêahttp://lattes.cnpq.br/0157452280626031http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4778268P199cf4bf1-cbcf-4e0b-8765-fc24463ecb452016-06-02T19:56:59Z2005-06-302016-06-02T19:56:59Z2005-04-08ROCHA, Kleper de Oliveira. Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano.. 2005. 90 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2005.https://repositorio.ufscar.br/handle/ufscar/417015%Ni/Al2O3 catalysts was obtained by impregnation with Ni(NO3)2 aqueous solution and promoted with Au and Ag. The Au was successively impregnated with aqueous solution of [Au(NH3)4](NO3)3. The Ag was coimpregnated with aqueous solution of AgNO3- Ni(NO3)2. The effect of Ag and Au on the catalytic behavior of Ni/Al2O3 catalysts in the reaction of steam reforming of CH4 was elucidate. The catalysts were characterized by temperatureprogrammed reduction (TPR), temperature-programmed dessorption of H2 (TPDH2) and Fourier transform infrared spectroscopy (FTIR) of CO adsorption. TPR results indicated that NiO is in weak interaction with support and the temperature reduction of NiO is independent of Ag and Au presence. FTIR data of CO adsorbed showed that Ag and Au suppress the CO adsorption in poli-coordination relative to the linear CO. Ag or Au on the Ni surface presents a determinant role in the block of graphitic carbon formation in the reaction of steam reforming of CH4. The fit of Arrhenius equation to rate of the total reaction showed a compensation effect between the apparent activation energy (Ea ap) and logarithmic of prefactor (k0). The linear increase of Ea ap with rise of lnk0 is observed increasing Ag and Au loading, which is followed by decreasing of the catalytic activity. Theses results suggest that the CHx intermediates, formed in the determinant stage of global velocity, show low interaction of with surface of Ni. The increase of the resistance for graphite formation by presence of Ag or Au is mainly attributed to the block of highly uncoordinated Ni atoms, which are higher activity to activation of CH4 and act as nucleation site for graphite formation.Catalisadores de 15%Ni/Al2O3 foram preparados por impregnação com solução aquosa de Ni(NO3)2 e promovidos com Au e Ag. O Au foi adicionado através da impregnação sucessiva da solução aquosa de [Au(NH3)4](NO3)3. A Ag foi adicionada por co-impregnação com solução aquosa de AgNO3-Ni(NO3)2. O efeito da Ag e do Au no comportamento catalítico do Ni/Al2O3 foi verificado na reforma a vapor do CH4. Os catalisadores foram caracterizados por redução a temperatura programada (TPR), dessorção a temperatura programada de H2 (TPDH2) e espectroscopia no infravermelho do CO adsorvido com transformada de Fourier (FTIR). Resultados de TPR indicaram que o NiO está em baixa interação com o suporte e a temperatura de redução do NiO é independe da presença de Ag ou Au. Dados de FTIR do CO adsorvido mostram que a Ag e Au suprimem a adsorção do CO poli-coordenado em relação ao CO linear. Ag ou Au sobre a superfície do Ni apresenta um papel determinante no bloqueio de formação de carbono grafítico na reforma a vapor do CH4. O ajuste da equação de Arrhenius à taxa total de reação mostra um efeito de compensação entre a energia de ativação aparente (Ea ap) e o logarítmico do fator pré-exponencial (k0). O aumento da linar da Ea ap com o aumento do lnk0 é observado aumentando o teor de Ag e Au, o qual é seguido pelo decréscimo da atividade catalítica. Estes resultados sugerem que os intermediários CHx, formados na etapa determinante da velocidade global, mostram uma baixa interação com a superfície do Ni. O aumento da resistência à formação de grafíte pela presença de Ag e Au é atribuído principalmente ao bloqueio dos átomos de Ni de baixa coordenação, os quais são altamente ativos para ativação do CH4 e atuam como sítios nucleadores da formação de grafite.Universidade Federal de Sao Carlosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Engenharia Química - PPGEQUFSCarBRCatalisadoresCinéticaPreparação de amostra (química analítica)Energia de ativaçãoEfeito de compensaçãoENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICACatalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metanoinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesis-1-13b275236-acc5-4218-a33b-8f802e7f5a18info:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALDissKOR.pdfapplication/pdf1016506https://repositorio.ufscar.br/bitstream/ufscar/4170/1/DissKOR.pdffc76d477ed99b6def21ffb265654fc0cMD51THUMBNAILDissKOR.pdf.jpgDissKOR.pdf.jpgIM Thumbnailimage/jpeg7828https://repositorio.ufscar.br/bitstream/ufscar/4170/2/DissKOR.pdf.jpgd6a44be95695d728d6f63ae1d735dd7bMD52ufscar/41702023-09-18 18:32:22.128oai:repositorio.ufscar.br:ufscar/4170Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:32:22Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
title |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
spellingShingle |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano Rocha, Kleper de Oliveira Catalisadores Cinética Preparação de amostra (química analítica) Energia de ativação Efeito de compensação ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA |
title_short |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
title_full |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
title_fullStr |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
title_full_unstemmed |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
title_sort |
Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano |
author |
Rocha, Kleper de Oliveira |
author_facet |
Rocha, Kleper de Oliveira |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4778268P1 |
dc.contributor.author.fl_str_mv |
Rocha, Kleper de Oliveira |
dc.contributor.advisor1.fl_str_mv |
Bueno, José Maria Corrêa |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/0157452280626031 |
dc.contributor.authorID.fl_str_mv |
99cf4bf1-cbcf-4e0b-8765-fc24463ecb45 |
contributor_str_mv |
Bueno, José Maria Corrêa |
dc.subject.por.fl_str_mv |
Catalisadores Cinética Preparação de amostra (química analítica) Energia de ativação Efeito de compensação |
topic |
Catalisadores Cinética Preparação de amostra (química analítica) Energia de ativação Efeito de compensação ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA |
description |
15%Ni/Al2O3 catalysts was obtained by impregnation with Ni(NO3)2 aqueous solution and promoted with Au and Ag. The Au was successively impregnated with aqueous solution of [Au(NH3)4](NO3)3. The Ag was coimpregnated with aqueous solution of AgNO3- Ni(NO3)2. The effect of Ag and Au on the catalytic behavior of Ni/Al2O3 catalysts in the reaction of steam reforming of CH4 was elucidate. The catalysts were characterized by temperatureprogrammed reduction (TPR), temperature-programmed dessorption of H2 (TPDH2) and Fourier transform infrared spectroscopy (FTIR) of CO adsorption. TPR results indicated that NiO is in weak interaction with support and the temperature reduction of NiO is independent of Ag and Au presence. FTIR data of CO adsorbed showed that Ag and Au suppress the CO adsorption in poli-coordination relative to the linear CO. Ag or Au on the Ni surface presents a determinant role in the block of graphitic carbon formation in the reaction of steam reforming of CH4. The fit of Arrhenius equation to rate of the total reaction showed a compensation effect between the apparent activation energy (Ea ap) and logarithmic of prefactor (k0). The linear increase of Ea ap with rise of lnk0 is observed increasing Ag and Au loading, which is followed by decreasing of the catalytic activity. Theses results suggest that the CHx intermediates, formed in the determinant stage of global velocity, show low interaction of with surface of Ni. The increase of the resistance for graphite formation by presence of Ag or Au is mainly attributed to the block of highly uncoordinated Ni atoms, which are higher activity to activation of CH4 and act as nucleation site for graphite formation. |
publishDate |
2005 |
dc.date.available.fl_str_mv |
2005-06-30 2016-06-02T19:56:59Z |
dc.date.issued.fl_str_mv |
2005-04-08 |
dc.date.accessioned.fl_str_mv |
2016-06-02T19:56:59Z |
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 |
ROCHA, Kleper de Oliveira. Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano.. 2005. 90 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2005. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/4170 |
identifier_str_mv |
ROCHA, Kleper de Oliveira. Catalisadores de Ni/Al2O3 promovidos com Au e Ag aplicados à reforma a vapor do metano.. 2005. 90 f. Dissertação (Mestrado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2005. |
url |
https://repositorio.ufscar.br/handle/ufscar/4170 |
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por |
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-1 -1 |
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3b275236-acc5-4218-a33b-8f802e7f5a18 |
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info:eu-repo/semantics/openAccess |
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openAccess |
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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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