Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC
Main Author: | |
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Publication Date: | 2020 |
Format: | Bachelor thesis |
Language: | eng |
Source: | Repositório Institucional da UFSCAR |
Download full: | https://repositorio.ufscar.br/handle/ufscar/13003 |
Summary: | Proton-exchange membrane fuel cells (PEMFCs) are promising candidates for the green conversion of hydrogen into electric energy. A considerable problem pre-venting the large-scale applications of PEMFCs is the inadequate durability of the supported electrocatalyst layer. Carbon blacks (CBs) such as Vulcan XC-72 are commonly used as the carbon support, however its stability is limiting for long term PEMFC use. CB in the cathode is oxidized in the PEMFC start and stop cycles, detaching the Pt nanoparticles and promoting their agglomeration, which leads to performance loss. This degradation is due to the high potentials caused by fuel starvation and to the accelerated corrosion rate induced by the Pt catalysts. Boron-doped diamond (BDD) has interesting properties, such as high chemical and thermal stability, that make it desirable as a PEMFC electrocatalyst support material. The most widespread method for producing BDD is chemical vapor dep-osition (CVD), since it is efficient in dopant control and makes diamond with consistent characteristics. The physicochemical and electrical properties of BDD are affected by the amount of non-diamond carbon (NDC) present in the diamond matrix, by the grain size and by the boron doping. All of this in turn are controlled by the CVD conditions that are employed, such as source gas mixture ratios and deposition pressure/power. BDD can be synthesized as a film or a powder; the latter is most wanted for energy applications as it has a higher surface area. BDD particles can be synthesized by a core-shell approach, in which a powder sub-strate, such as nanodiamond or glassy carbon, is coated with a layer of BDD. The BDD overlayer can be observed with scanning electron microscopy (SEM), which allows the assessment of the particles’ morphology. Raman spectroscopy is widely used for evaluation of the BDD microstructure, as BDD materials have a wide range of Raman spectra that correlate with the amount of NDC, grain size and defect density. SEM and Raman spectroscopy enable the distinction of sp2 and sp3 bonded carbon domains, which allows the correlation of the BDD mate- 6 rials’ microstructure with the observed electrochemical properties. These proper-ties can be evaluated by cyclic voltammetry, in which redox peaks may be ob-served due to the presence of NDC. Additionally, redox probes such as [Fe(CN)6]3–/4– can be used, with the electrochemical response being sensitive to the surface or electronic properties of BDD. Anodic polarization is used to analyze the stability of the powders, as less-stable powders show more extensive oxida-tion. Finally, it is possible to attach Pt nanoparticles to BDD to test their viability as electrocatalyst support. After attachment of the Pt nanoparticles, it is possible to evaluate the performance and durability of the potential BDD supports with the previously mentioned electrochemical techniques and with accelerated long-term stability tests. |
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Mattoso, Samuel HenriqueRocha Filho, Romeu Cardozohttp://lattes.cnpq.br/5200717413563550http://lattes.cnpq.br/70214377530632592020-07-03T12:12:56Z2020-07-03T12:12:56Z2020-06-19MATTOSO, Samuel Henrique. Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC. 2020. Trabalho de Conclusão de Curso (Graduação em Química) – Universidade Federal de São Carlos, São Carlos, 2020. Disponível em: https://repositorio.ufscar.br/handle/ufscar/13003.https://repositorio.ufscar.br/handle/ufscar/13003Proton-exchange membrane fuel cells (PEMFCs) are promising candidates for the green conversion of hydrogen into electric energy. A considerable problem pre-venting the large-scale applications of PEMFCs is the inadequate durability of the supported electrocatalyst layer. Carbon blacks (CBs) such as Vulcan XC-72 are commonly used as the carbon support, however its stability is limiting for long term PEMFC use. CB in the cathode is oxidized in the PEMFC start and stop cycles, detaching the Pt nanoparticles and promoting their agglomeration, which leads to performance loss. This degradation is due to the high potentials caused by fuel starvation and to the accelerated corrosion rate induced by the Pt catalysts. Boron-doped diamond (BDD) has interesting properties, such as high chemical and thermal stability, that make it desirable as a PEMFC electrocatalyst support material. The most widespread method for producing BDD is chemical vapor dep-osition (CVD), since it is efficient in dopant control and makes diamond with consistent characteristics. The physicochemical and electrical properties of BDD are affected by the amount of non-diamond carbon (NDC) present in the diamond matrix, by the grain size and by the boron doping. All of this in turn are controlled by the CVD conditions that are employed, such as source gas mixture ratios and deposition pressure/power. BDD can be synthesized as a film or a powder; the latter is most wanted for energy applications as it has a higher surface area. BDD particles can be synthesized by a core-shell approach, in which a powder sub-strate, such as nanodiamond or glassy carbon, is coated with a layer of BDD. The BDD overlayer can be observed with scanning electron microscopy (SEM), which allows the assessment of the particles’ morphology. Raman spectroscopy is widely used for evaluation of the BDD microstructure, as BDD materials have a wide range of Raman spectra that correlate with the amount of NDC, grain size and defect density. SEM and Raman spectroscopy enable the distinction of sp2 and sp3 bonded carbon domains, which allows the correlation of the BDD mate- 6 rials’ microstructure with the observed electrochemical properties. These proper-ties can be evaluated by cyclic voltammetry, in which redox peaks may be ob-served due to the presence of NDC. Additionally, redox probes such as [Fe(CN)6]3–/4– can be used, with the electrochemical response being sensitive to the surface or electronic properties of BDD. Anodic polarization is used to analyze the stability of the powders, as less-stable powders show more extensive oxida-tion. Finally, it is possible to attach Pt nanoparticles to BDD to test their viability as electrocatalyst support. After attachment of the Pt nanoparticles, it is possible to evaluate the performance and durability of the potential BDD supports with the previously mentioned electrochemical techniques and with accelerated long-term stability tests.Células a combustível de membrana trocadora de prótons (PEMFCs) são candi-datas promissoras para a conversão verde de hidrogênio em energia elétrica. Um problema considerável obstruindo a implementação em larga escala de PEMFCs é a durabilidade inadequada dos materiais componentes, como a degradação da camada eletrocatalítica suportada. Negros de fumo (CB), como Vulcan XC-72, são comumente usados como o suporte de carbono, contudo a sua estabilidade é limitante para o uso prolongado de PEMFCs. CB no catodo é oxidado na ciclagem de liga e desliga da PEMFC, desprendendo nanopartículas de Pt e formando aglo-merados, levando a uma queda de desempenho. Essa degradação é devido aos potenciais elevados causados por escassez de combustível e à taxa de corrosão acelerada induzida pelos catalisadores de Pt. Diamante dopado com boro (BDD) possui propriedades interessantes, como alta estabilidade química e térmica, o que o faz um candidato como material de suporte de eletrocatalisador de PEMFC. O método mais comum para a produção de BDD é a deposição química em fase de vapor, pois é eficiente no controle de dopagem e também produz diamante com características consistentes. As propriedades físico-químicas e eletroquímicas do BDD são afetadas pela quantidade de carbono não diamante (NDC) presente na matriz do diamante, pelo tamanho de grão e pela dopagem de boro. Todas essas características são controladas pelas condições de CVD que são utilizadas, como concentração dos gases da fonte e pressão/potência de deposição. BDD pode ser sintetizado como um filme ou um pó, sendo que pós são mais procurados para aplicações em energia devido às suas maiores áreas específicas. Partículas de BDD podem ser sintetizadas através de um método core-shell, no qual um subs-trato em pó, como nanodiamante ou carbono vítreo, é recoberto com uma camada de BDD. A camada de BDD pode ser observada por microscopia eletrônica de varredura (SEM), que permite avaliar a morfologia das partículas. Espectroscopia Raman é comumente usada para examinar a microestrutura de BDD, sendo que 4 materiais de BDD apresentam uma grande variedade de espectros Raman que es-tão correlacionados com a quantidade de NDC, tamanho de grão e densidade de defeitos. SEM e espectroscopia Raman permitem a distinção de domínios de car-bono sp2 e sp3, o que permite a correlação da microestrutura dos materiais de BDD com as propriedades eletroquímicas observadas. Essas propriedades podem ser avaliadas por voltametria cíclica, na qual picos redox podem ser observados de-vido à presença de NDC. Além disso, sistemas redox como [Fe(CN)6]3−/4− podem ser utilizados, sendo que a sua resposta eletroquímica é sensível a propriedades de superfície ou eletrônicas do BDD. Polarização anódica é usada para analisar a estabilidade dos pós, sendo que pós menos estáveis demonstram maior oxidação. Finalmente, é possível fixar nanopartículas de Pt ao BDD para testar sua viabili-dade como possível suporte de eletrocatalisador. Após a fixação das nanopartícu-las ao BDD, é possível avaliar o desempenho e durabilidade dos potenciais supor-tes de BDD com as técnicas mencionadas previamente e com testes acelerados de estabilidade a longo prazo.Não recebi financiamentoengUniversidade Federal de São CarlosCâmpus São CarlosQuímica - QL-ArUFSCarAttribution-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nd/3.0/br/info:eu-repo/semantics/openAccessCélulas a combustível de membrana trocadora de prótonsDiamante dopado com boroSuporte de eletrocatalisadorDeposição química em fase de vaporCarbono não diamanteEspectroscopia Raman.Voltametria cíclicaCIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICADiamante dopado com boro como um possível suporte de eletrocatalisador de PEMFCBoron-doped diamond as a possible PEMFC electrocatalyst support materialinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/bachelorThesisreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALTCC- Samuel Mattoso Final Repositório.pdfTCC- Samuel Mattoso Final Repositório.pdfapplication/pdf2340949https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/13003/1/TCC-%20Samuel%20Mattoso%20Final%20Reposit%c3%b3rio.pdfc93bb1a9c00bf811e66f1b49283ed34eMD51CC-LICENSElicense_rdflicense_rdfapplication/rdf+xml; charset=utf-8805https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/13003/2/license_rdfc4c98de35c20c53220c07884f4def27cMD52TEXTTCC- Samuel Mattoso Final Repositório.pdf.txtTCC- Samuel Mattoso Final Repositório.pdf.txtExtracted texttext/plain98086https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/13003/3/TCC-%20Samuel%20Mattoso%20Final%20Reposit%c3%b3rio.pdf.txtcc7e105c856bf5620f2def36d8a5320cMD53THUMBNAILTCC- Samuel Mattoso Final Repositório.pdf.jpgTCC- Samuel Mattoso Final Repositório.pdf.jpgIM Thumbnailimage/jpeg7843https://{{ getenv "DSPACE_HOST" "repositorio.ufscar.br" }}/bitstream/ufscar/13003/4/TCC-%20Samuel%20Mattoso%20Final%20Reposit%c3%b3rio.pdf.jpg2623295f53357ef2e36ae955ab2d5be3MD54ufscar/130032021-01-11 14:34:54.642oai:repositorio.ufscar.br:ufscar/13003Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222021-01-11T14:34:54Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
dc.title.alternative.por.fl_str_mv |
Boron-doped diamond as a possible PEMFC electrocatalyst support material |
title |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
spellingShingle |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC Mattoso, Samuel Henrique Células a combustível de membrana trocadora de prótons Diamante dopado com boro Suporte de eletrocatalisador Deposição química em fase de vapor Carbono não diamante Espectroscopia Raman. Voltametria cíclica CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA |
title_short |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
title_full |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
title_fullStr |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
title_full_unstemmed |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
title_sort |
Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC |
author |
Mattoso, Samuel Henrique |
author_facet |
Mattoso, Samuel Henrique |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/7021437753063259 |
dc.contributor.author.fl_str_mv |
Mattoso, Samuel Henrique |
dc.contributor.advisor1.fl_str_mv |
Rocha Filho, Romeu Cardozo |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/5200717413563550 |
contributor_str_mv |
Rocha Filho, Romeu Cardozo |
dc.subject.por.fl_str_mv |
Células a combustível de membrana trocadora de prótons Diamante dopado com boro Suporte de eletrocatalisador Deposição química em fase de vapor Carbono não diamante Espectroscopia Raman. Voltametria cíclica |
topic |
Células a combustível de membrana trocadora de prótons Diamante dopado com boro Suporte de eletrocatalisador Deposição química em fase de vapor Carbono não diamante Espectroscopia Raman. Voltametria cíclica CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA |
description |
Proton-exchange membrane fuel cells (PEMFCs) are promising candidates for the green conversion of hydrogen into electric energy. A considerable problem pre-venting the large-scale applications of PEMFCs is the inadequate durability of the supported electrocatalyst layer. Carbon blacks (CBs) such as Vulcan XC-72 are commonly used as the carbon support, however its stability is limiting for long term PEMFC use. CB in the cathode is oxidized in the PEMFC start and stop cycles, detaching the Pt nanoparticles and promoting their agglomeration, which leads to performance loss. This degradation is due to the high potentials caused by fuel starvation and to the accelerated corrosion rate induced by the Pt catalysts. Boron-doped diamond (BDD) has interesting properties, such as high chemical and thermal stability, that make it desirable as a PEMFC electrocatalyst support material. The most widespread method for producing BDD is chemical vapor dep-osition (CVD), since it is efficient in dopant control and makes diamond with consistent characteristics. The physicochemical and electrical properties of BDD are affected by the amount of non-diamond carbon (NDC) present in the diamond matrix, by the grain size and by the boron doping. All of this in turn are controlled by the CVD conditions that are employed, such as source gas mixture ratios and deposition pressure/power. BDD can be synthesized as a film or a powder; the latter is most wanted for energy applications as it has a higher surface area. BDD particles can be synthesized by a core-shell approach, in which a powder sub-strate, such as nanodiamond or glassy carbon, is coated with a layer of BDD. The BDD overlayer can be observed with scanning electron microscopy (SEM), which allows the assessment of the particles’ morphology. Raman spectroscopy is widely used for evaluation of the BDD microstructure, as BDD materials have a wide range of Raman spectra that correlate with the amount of NDC, grain size and defect density. SEM and Raman spectroscopy enable the distinction of sp2 and sp3 bonded carbon domains, which allows the correlation of the BDD mate- 6 rials’ microstructure with the observed electrochemical properties. These proper-ties can be evaluated by cyclic voltammetry, in which redox peaks may be ob-served due to the presence of NDC. Additionally, redox probes such as [Fe(CN)6]3–/4– can be used, with the electrochemical response being sensitive to the surface or electronic properties of BDD. Anodic polarization is used to analyze the stability of the powders, as less-stable powders show more extensive oxida-tion. Finally, it is possible to attach Pt nanoparticles to BDD to test their viability as electrocatalyst support. After attachment of the Pt nanoparticles, it is possible to evaluate the performance and durability of the potential BDD supports with the previously mentioned electrochemical techniques and with accelerated long-term stability tests. |
publishDate |
2020 |
dc.date.accessioned.fl_str_mv |
2020-07-03T12:12:56Z |
dc.date.available.fl_str_mv |
2020-07-03T12:12:56Z |
dc.date.issued.fl_str_mv |
2020-06-19 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/bachelorThesis |
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bachelorThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
MATTOSO, Samuel Henrique. Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC. 2020. Trabalho de Conclusão de Curso (Graduação em Química) – Universidade Federal de São Carlos, São Carlos, 2020. Disponível em: https://repositorio.ufscar.br/handle/ufscar/13003. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/13003 |
identifier_str_mv |
MATTOSO, Samuel Henrique. Diamante dopado com boro como um possível suporte de eletrocatalisador de PEMFC. 2020. Trabalho de Conclusão de Curso (Graduação em Química) – Universidade Federal de São Carlos, São Carlos, 2020. Disponível em: https://repositorio.ufscar.br/handle/ufscar/13003. |
url |
https://repositorio.ufscar.br/handle/ufscar/13003 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
Attribution-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nd/3.0/br/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nd/3.0/br/ |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
Universidade Federal de São Carlos Câmpus São Carlos Química - QL-Ar |
dc.publisher.initials.fl_str_mv |
UFSCar |
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Universidade Federal de São Carlos Câmpus São Carlos Química - QL-Ar |
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