Catalytic properties of titanate nanotubes applied to dry reforming of methane

Detalhes bibliográficos
Autor(a) principal: Davi Coelho de Carvalho
Data de Publicação: 2016
Tipo de documento: Dissertação
Idioma: por
Título da fonte: Biblioteca Digital de Teses e Dissertações da UFC
Texto Completo: http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16535
Resumo: Dry reforming of methane reaction was conducted in the presence of titanate nanotubes (TNTs) modified with Co, Ni and Pt. TNTs were synthesized by hydrothermal treatment and than these solids were either submitted to ion exchange for Ni and Co using hexahydrate nitrate solutions, or they were submitted to wet impregnation with H2Ptl6.6H2O (1% w/w of Pt) solution. The solids were characterized before and after the dry reforming of methane by elemental chemical analysis (CHN), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, thermoprogrammed reduction (TPR), CO2 thermoprogrammed desorption (CO2-TPD), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Raman and XRD results showed the presence of Na2Ti3O7 phase to all sodic nanotubes, while that the nanotubes modified displayed peaks and vibrational modes relative to CoTi3O7, NiTi3O7 and PtOx/Na2Ti3O7 phases. TEM images exhibited tubular morphology composed by multi-walls, as observed by XRD and Raman. SEM-EDS results showed the nanotubes composition with M/Ti ratio lower than the theoretical (value of 0,33), due to the presence of structural water. The XPS results confirmed the presence of M(OH)2 phase (M=Co, Ni or Pt) present on nanotubes surface. TPR patterns suggested the formation of M0/MTiO3 (M = Co, Ni and Pt) after the reduction of the nanotubes at 650 ÂC. The nitrogen adsorption-desorption isotherms of sodic and modified TNTs showed isotherms type IV with an essentially mesoporous structure. CO2-TPD patterns suggested the presence of weak and moderate basic sites in all catalysts, indicating phase transformation due to the decomposition, in situ, of as-prepared nanotubes. The catalyst NiTNT exhibited the highest CO2 and methane conversion at 600 ÂC, with about 43 and 25%, respectively, and H2/CO ratio equal 1, without deactivation over time. PtTNT was lesser susceptible to coking, although sintering remarkably decreased the performance of this solid. On the other hand, PtTNT and CoTNT showed formation of coke over the PtOx/PtTiO3 and Co0/CoTiO3 active phase, respectively, so that the latter solid deactivated during the dry reforming of methane.
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spelling info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisCatalytic properties of titanate nanotubes applied to dry reforming of methanePropriedades catalÃticas de nanotubos de titanatos aplicados na reforma seca do metano2016-03-02AlcinÃia ConceiÃÃo Oliveira91889561568http://lattes.cnpq.br/1188799440810495Josuà Mendes Filho00215350359http://lattes.cnpq.br/1526059419518620Diana Cristina Silva de Azevedo31021409391 0515140430http://lattes.cnpq.br/0603889353822474Davi Coelho de CarvalhoUniversidade Federal do CearÃPrograma de PÃs-GraduaÃÃo em Engenharia QuÃmicaUFCBRReforma seca do metano Nanotubos de titanatos CoqueDry reforming of methane Titanate nanotubes Characterization CokeENGENHARIA QUIMICADry reforming of methane reaction was conducted in the presence of titanate nanotubes (TNTs) modified with Co, Ni and Pt. TNTs were synthesized by hydrothermal treatment and than these solids were either submitted to ion exchange for Ni and Co using hexahydrate nitrate solutions, or they were submitted to wet impregnation with H2Ptl6.6H2O (1% w/w of Pt) solution. The solids were characterized before and after the dry reforming of methane by elemental chemical analysis (CHN), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, thermoprogrammed reduction (TPR), CO2 thermoprogrammed desorption (CO2-TPD), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Raman and XRD results showed the presence of Na2Ti3O7 phase to all sodic nanotubes, while that the nanotubes modified displayed peaks and vibrational modes relative to CoTi3O7, NiTi3O7 and PtOx/Na2Ti3O7 phases. TEM images exhibited tubular morphology composed by multi-walls, as observed by XRD and Raman. SEM-EDS results showed the nanotubes composition with M/Ti ratio lower than the theoretical (value of 0,33), due to the presence of structural water. The XPS results confirmed the presence of M(OH)2 phase (M=Co, Ni or Pt) present on nanotubes surface. TPR patterns suggested the formation of M0/MTiO3 (M = Co, Ni and Pt) after the reduction of the nanotubes at 650 ÂC. The nitrogen adsorption-desorption isotherms of sodic and modified TNTs showed isotherms type IV with an essentially mesoporous structure. CO2-TPD patterns suggested the presence of weak and moderate basic sites in all catalysts, indicating phase transformation due to the decomposition, in situ, of as-prepared nanotubes. The catalyst NiTNT exhibited the highest CO2 and methane conversion at 600 ÂC, with about 43 and 25%, respectively, and H2/CO ratio equal 1, without deactivation over time. PtTNT was lesser susceptible to coking, although sintering remarkably decreased the performance of this solid. On the other hand, PtTNT and CoTNT showed formation of coke over the PtOx/PtTiO3 and Co0/CoTiO3 active phase, respectively, so that the latter solid deactivated during the dry reforming of methane.A reaÃÃo da reforma seca do metano foi conduzida na presenÃa de nanotubos de titanatos (TNTs) modificados com Co, Ni e Pt. Os TNTs foram sintetizados via tratamento hidrotÃrmico e, posteriormente, foram submetidos à troca iÃnica por Ni e Co, utilizando soluÃÃes de nitrato hexahidratado, ou foram submetidos à impregnaÃÃo via-Ãmida com soluÃÃo de H2PtCl6.6H2O (1% m/m de Pt). Os catalisadores foram caracterizados antes e apÃs reaÃÃo de reforma seca do metano por anÃlise quÃmica (CHN), difraÃÃo de raios-X (DRX), espectroscopia Raman, isotermas de adsorÃÃo-dessorÃÃo de nitrogÃnio, reduÃÃo termoprogramada (TPR), dessorÃÃo termoprogramada de CO2 (TPD-CO2), microscopia eletrÃnica de transmissÃo (TEM), microscopia eletrÃnica de varredura (MEV-EDS) e espectroscopia fotoeletrÃnica de raios-X (XPS). Os resultados de Raman e DRX evidenciaram a presenÃa da fase Na2Ti3O7 para os nanotubos sÃdicos, enquanto que para os nanotubos modificados foram identificados picos e modos vibracionais referentes Ãs fases CoTi3O7, NiTi3O7 e PtOx/Na2Ti3O7. As imagens de TEM exibiram morfologia tubular composta por multiparedes, corroborando com os resultados de DRX e Raman. Os resultados de MEV-EDS mostraram a composiÃÃo dos nanotubos com razÃo M/Ti menor que o teÃrico (0,33), devido à presenÃa de Ãgua estrutural. Os resultados de XPS confirmaram a existÃncia da fase M(OH)2 (M=Co, Ni ou Pt) presentes na superfÃcie dos nanotubos. As curvas de TPR sugeriram a formaÃÃo da fase M0/MTiO3 (M = Co, Ni e Pt), apÃs a reduÃÃo dos nanotubos a 650 ÂC. As isotermas de adsorÃÃo-dessorÃÃo de nitrogÃnio dos TNTs sÃdicos e modificados apresentaram isotermas do tipo IV com estrutura essencialmente formada por mesoporos. Os perfis de TPD-CO2 sugeriram a presenÃa de sÃtios bÃsicos fracos e moderados em todos os catalisadores, indicando mudanÃa de fase devido à decomposiÃÃo in situ dos nanotubos como sintetizados. O catalisador NiTNT apresentou os melhores resultados de conversÃo de CO2 e metano a 600 ÂC, com aproximadamente 43 e 25%, respectivamente, e razÃo H2/CO igual a 0,5, sem desativaÃÃo ao longo do tempo. PtTNT foi menos susceptÃvel à formaÃÃo de coque, embora o fenÃmeno de sinterizaÃÃo tenha desfavorecido o desempenho do sÃlido. Por outro lado, os sÃlidos PtTNT e CoTNT apresentaram formaÃÃo de coque sobre as fases ativas PtOx/PtTiO3 e Co0/CoTiO3, respectivamente, de modo que este Ãltimo sÃlido desativou durante a reaÃÃo da reforma seca do metano. CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16535application/pdfinfo:eu-repo/semantics/openAccessporreponame:Biblioteca Digital de Teses e Dissertações da UFCinstname:Universidade Federal do Cearáinstacron:UFC2019-01-21T11:29:54Zmail@mail.com -
dc.title.en.fl_str_mv Catalytic properties of titanate nanotubes applied to dry reforming of methane
dc.title.alternative.pt.fl_str_mv Propriedades catalÃticas de nanotubos de titanatos aplicados na reforma seca do metano
title Catalytic properties of titanate nanotubes applied to dry reforming of methane
spellingShingle Catalytic properties of titanate nanotubes applied to dry reforming of methane
Davi Coelho de Carvalho
Reforma seca do metano
Nanotubos de titanatos
Coque
Dry reforming of methane
Titanate nanotubes
Characterization
Coke
ENGENHARIA QUIMICA
title_short Catalytic properties of titanate nanotubes applied to dry reforming of methane
title_full Catalytic properties of titanate nanotubes applied to dry reforming of methane
title_fullStr Catalytic properties of titanate nanotubes applied to dry reforming of methane
title_full_unstemmed Catalytic properties of titanate nanotubes applied to dry reforming of methane
title_sort Catalytic properties of titanate nanotubes applied to dry reforming of methane
author Davi Coelho de Carvalho
author_facet Davi Coelho de Carvalho
author_role author
dc.contributor.advisor1.fl_str_mv AlcinÃia ConceiÃÃo Oliveira
dc.contributor.advisor1ID.fl_str_mv 91889561568
dc.contributor.advisor1Lattes.fl_str_mv http://lattes.cnpq.br/1188799440810495
dc.contributor.advisor-co1.fl_str_mv Josuà Mendes Filho
dc.contributor.advisor-co1ID.fl_str_mv 00215350359
dc.contributor.advisor-co1Lattes.fl_str_mv http://lattes.cnpq.br/1526059419518620
dc.contributor.referee1.fl_str_mv Diana Cristina Silva de Azevedo
dc.contributor.referee1ID.fl_str_mv 31021409391
dc.contributor.authorID.fl_str_mv 0515140430
dc.contributor.authorLattes.fl_str_mv http://lattes.cnpq.br/0603889353822474
dc.contributor.author.fl_str_mv Davi Coelho de Carvalho
contributor_str_mv AlcinÃia ConceiÃÃo Oliveira
Josuà Mendes Filho
Diana Cristina Silva de Azevedo
dc.subject.por.fl_str_mv Reforma seca do metano
Nanotubos de titanatos
Coque
topic Reforma seca do metano
Nanotubos de titanatos
Coque
Dry reforming of methane
Titanate nanotubes
Characterization
Coke
ENGENHARIA QUIMICA
dc.subject.eng.fl_str_mv Dry reforming of methane
Titanate nanotubes
Characterization
Coke
dc.subject.cnpq.fl_str_mv ENGENHARIA QUIMICA
dc.description.sponsorship.fl_txt_mv CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
dc.description.abstract.por.fl_txt_mv Dry reforming of methane reaction was conducted in the presence of titanate nanotubes (TNTs) modified with Co, Ni and Pt. TNTs were synthesized by hydrothermal treatment and than these solids were either submitted to ion exchange for Ni and Co using hexahydrate nitrate solutions, or they were submitted to wet impregnation with H2Ptl6.6H2O (1% w/w of Pt) solution. The solids were characterized before and after the dry reforming of methane by elemental chemical analysis (CHN), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, thermoprogrammed reduction (TPR), CO2 thermoprogrammed desorption (CO2-TPD), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Raman and XRD results showed the presence of Na2Ti3O7 phase to all sodic nanotubes, while that the nanotubes modified displayed peaks and vibrational modes relative to CoTi3O7, NiTi3O7 and PtOx/Na2Ti3O7 phases. TEM images exhibited tubular morphology composed by multi-walls, as observed by XRD and Raman. SEM-EDS results showed the nanotubes composition with M/Ti ratio lower than the theoretical (value of 0,33), due to the presence of structural water. The XPS results confirmed the presence of M(OH)2 phase (M=Co, Ni or Pt) present on nanotubes surface. TPR patterns suggested the formation of M0/MTiO3 (M = Co, Ni and Pt) after the reduction of the nanotubes at 650 ÂC. The nitrogen adsorption-desorption isotherms of sodic and modified TNTs showed isotherms type IV with an essentially mesoporous structure. CO2-TPD patterns suggested the presence of weak and moderate basic sites in all catalysts, indicating phase transformation due to the decomposition, in situ, of as-prepared nanotubes. The catalyst NiTNT exhibited the highest CO2 and methane conversion at 600 ÂC, with about 43 and 25%, respectively, and H2/CO ratio equal 1, without deactivation over time. PtTNT was lesser susceptible to coking, although sintering remarkably decreased the performance of this solid. On the other hand, PtTNT and CoTNT showed formation of coke over the PtOx/PtTiO3 and Co0/CoTiO3 active phase, respectively, so that the latter solid deactivated during the dry reforming of methane.
A reaÃÃo da reforma seca do metano foi conduzida na presenÃa de nanotubos de titanatos (TNTs) modificados com Co, Ni e Pt. Os TNTs foram sintetizados via tratamento hidrotÃrmico e, posteriormente, foram submetidos à troca iÃnica por Ni e Co, utilizando soluÃÃes de nitrato hexahidratado, ou foram submetidos à impregnaÃÃo via-Ãmida com soluÃÃo de H2PtCl6.6H2O (1% m/m de Pt). Os catalisadores foram caracterizados antes e apÃs reaÃÃo de reforma seca do metano por anÃlise quÃmica (CHN), difraÃÃo de raios-X (DRX), espectroscopia Raman, isotermas de adsorÃÃo-dessorÃÃo de nitrogÃnio, reduÃÃo termoprogramada (TPR), dessorÃÃo termoprogramada de CO2 (TPD-CO2), microscopia eletrÃnica de transmissÃo (TEM), microscopia eletrÃnica de varredura (MEV-EDS) e espectroscopia fotoeletrÃnica de raios-X (XPS). Os resultados de Raman e DRX evidenciaram a presenÃa da fase Na2Ti3O7 para os nanotubos sÃdicos, enquanto que para os nanotubos modificados foram identificados picos e modos vibracionais referentes Ãs fases CoTi3O7, NiTi3O7 e PtOx/Na2Ti3O7. As imagens de TEM exibiram morfologia tubular composta por multiparedes, corroborando com os resultados de DRX e Raman. Os resultados de MEV-EDS mostraram a composiÃÃo dos nanotubos com razÃo M/Ti menor que o teÃrico (0,33), devido à presenÃa de Ãgua estrutural. Os resultados de XPS confirmaram a existÃncia da fase M(OH)2 (M=Co, Ni ou Pt) presentes na superfÃcie dos nanotubos. As curvas de TPR sugeriram a formaÃÃo da fase M0/MTiO3 (M = Co, Ni e Pt), apÃs a reduÃÃo dos nanotubos a 650 ÂC. As isotermas de adsorÃÃo-dessorÃÃo de nitrogÃnio dos TNTs sÃdicos e modificados apresentaram isotermas do tipo IV com estrutura essencialmente formada por mesoporos. Os perfis de TPD-CO2 sugeriram a presenÃa de sÃtios bÃsicos fracos e moderados em todos os catalisadores, indicando mudanÃa de fase devido à decomposiÃÃo in situ dos nanotubos como sintetizados. O catalisador NiTNT apresentou os melhores resultados de conversÃo de CO2 e metano a 600 ÂC, com aproximadamente 43 e 25%, respectivamente, e razÃo H2/CO igual a 0,5, sem desativaÃÃo ao longo do tempo. PtTNT foi menos susceptÃvel à formaÃÃo de coque, embora o fenÃmeno de sinterizaÃÃo tenha desfavorecido o desempenho do sÃlido. Por outro lado, os sÃlidos PtTNT e CoTNT apresentaram formaÃÃo de coque sobre as fases ativas PtOx/PtTiO3 e Co0/CoTiO3, respectivamente, de modo que este Ãltimo sÃlido desativou durante a reaÃÃo da reforma seca do metano.
description Dry reforming of methane reaction was conducted in the presence of titanate nanotubes (TNTs) modified with Co, Ni and Pt. TNTs were synthesized by hydrothermal treatment and than these solids were either submitted to ion exchange for Ni and Co using hexahydrate nitrate solutions, or they were submitted to wet impregnation with H2Ptl6.6H2O (1% w/w of Pt) solution. The solids were characterized before and after the dry reforming of methane by elemental chemical analysis (CHN), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, thermoprogrammed reduction (TPR), CO2 thermoprogrammed desorption (CO2-TPD), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Raman and XRD results showed the presence of Na2Ti3O7 phase to all sodic nanotubes, while that the nanotubes modified displayed peaks and vibrational modes relative to CoTi3O7, NiTi3O7 and PtOx/Na2Ti3O7 phases. TEM images exhibited tubular morphology composed by multi-walls, as observed by XRD and Raman. SEM-EDS results showed the nanotubes composition with M/Ti ratio lower than the theoretical (value of 0,33), due to the presence of structural water. The XPS results confirmed the presence of M(OH)2 phase (M=Co, Ni or Pt) present on nanotubes surface. TPR patterns suggested the formation of M0/MTiO3 (M = Co, Ni and Pt) after the reduction of the nanotubes at 650 ÂC. The nitrogen adsorption-desorption isotherms of sodic and modified TNTs showed isotherms type IV with an essentially mesoporous structure. CO2-TPD patterns suggested the presence of weak and moderate basic sites in all catalysts, indicating phase transformation due to the decomposition, in situ, of as-prepared nanotubes. The catalyst NiTNT exhibited the highest CO2 and methane conversion at 600 ÂC, with about 43 and 25%, respectively, and H2/CO ratio equal 1, without deactivation over time. PtTNT was lesser susceptible to coking, although sintering remarkably decreased the performance of this solid. On the other hand, PtTNT and CoTNT showed formation of coke over the PtOx/PtTiO3 and Co0/CoTiO3 active phase, respectively, so that the latter solid deactivated during the dry reforming of methane.
publishDate 2016
dc.date.issued.fl_str_mv 2016-03-02
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
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dc.publisher.none.fl_str_mv Universidade Federal do CearÃ
dc.publisher.program.fl_str_mv Programa de PÃs-GraduaÃÃo em Engenharia QuÃmica
dc.publisher.initials.fl_str_mv UFC
dc.publisher.country.fl_str_mv BR
publisher.none.fl_str_mv Universidade Federal do CearÃ
dc.source.none.fl_str_mv reponame:Biblioteca Digital de Teses e Dissertações da UFC
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