Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties
Autor(a) principal: | |
---|---|
Data de Publicação: | 2019 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/12198 |
Resumo: | Semiconductors are promising catalysts for artificial photosynthesis, but to date, there is no consensus on the ideal photocatalyst for CO2 reduction. Among semiconductors used for CO2 reduction, Nb2O5 is a promising alternative, since it has characteristics useful for catalysis, such as surface groups capable of assisting catalytic processes and high chemical stability. However, Nb2O5 absorbs only UV radiation, thus large-scale application of the same under solar radiation is inefficient. Given this problem, the formation of heterojunctions between Nb2O5 and C3N4, a semiconductor that absorbs below 460 nm of the visible spectrum, was investigated in this thesis as an alternative method to improve the photocatalytic properties of Nb2O5. Initially, the ability of Nb2O5 to convert CO2 in C1 and C2 products under irradiation was studied since Nb2O5 is known for its high surface acidity, a factor that could decrease the interaction of CO2 with the surface of the catalyst. However, it was observed that the surface acidity of Nb2O5 favored the formation of CO due to the low interaction of this molecule with the surface of the catalyst. This finding showed that Nb2O5 is a possible catalyst for CO2 photoreduction reactions. Accordingly, the main characteristics of Nb2O5 was verified and alternative synthesis methods for the formation of heterojunctions between Nb2O5 and g-C3N4 were investigated in order to shift the absorption of Nb2O5 into the visible region and increase its photocatalytic performance. To that end, heteroaggregation induced by difference in superficial charge was chosen. The method proved efficient for the formation of g-C3N4/Nb2O5 heterostructures, where the Nb2O5 particles were homogeneously dispersed on the surface of g-C3N4, thus conferring an intimate contact between the particles, high sharing of photogenerated charges, and consequently high photocatalytic activity for the degradation of organic pollutants and conversion of CO2 into CH4. |
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Silva, Gelson Tiago dos Santos Tavares daOliveira, Cauê Ribeiro dehttp://lattes.cnpq.br/5321313558714462Paris, Elaine Cristinahttp://lattes.cnpq.br/8475640212486290http://lattes.cnpq.br/146354655242758909d1e4a7-99e5-48be-b961-68781e978b9c2020-01-30T18:14:39Z2020-01-30T18:14:39Z2019-04-22SILVA, Gelson Tiago dos Santos Tavares da. Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties. 2019. Tese (Doutorado em Química) – Universidade Federal de São Carlos, São Carlos, 2019. Disponível em: https://repositorio.ufscar.br/handle/ufscar/12198.https://repositorio.ufscar.br/handle/ufscar/12198Semiconductors are promising catalysts for artificial photosynthesis, but to date, there is no consensus on the ideal photocatalyst for CO2 reduction. Among semiconductors used for CO2 reduction, Nb2O5 is a promising alternative, since it has characteristics useful for catalysis, such as surface groups capable of assisting catalytic processes and high chemical stability. However, Nb2O5 absorbs only UV radiation, thus large-scale application of the same under solar radiation is inefficient. Given this problem, the formation of heterojunctions between Nb2O5 and C3N4, a semiconductor that absorbs below 460 nm of the visible spectrum, was investigated in this thesis as an alternative method to improve the photocatalytic properties of Nb2O5. Initially, the ability of Nb2O5 to convert CO2 in C1 and C2 products under irradiation was studied since Nb2O5 is known for its high surface acidity, a factor that could decrease the interaction of CO2 with the surface of the catalyst. However, it was observed that the surface acidity of Nb2O5 favored the formation of CO due to the low interaction of this molecule with the surface of the catalyst. This finding showed that Nb2O5 is a possible catalyst for CO2 photoreduction reactions. Accordingly, the main characteristics of Nb2O5 was verified and alternative synthesis methods for the formation of heterojunctions between Nb2O5 and g-C3N4 were investigated in order to shift the absorption of Nb2O5 into the visible region and increase its photocatalytic performance. To that end, heteroaggregation induced by difference in superficial charge was chosen. The method proved efficient for the formation of g-C3N4/Nb2O5 heterostructures, where the Nb2O5 particles were homogeneously dispersed on the surface of g-C3N4, thus conferring an intimate contact between the particles, high sharing of photogenerated charges, and consequently high photocatalytic activity for the degradation of organic pollutants and conversion of CO2 into CH4.Semicondutores são catalisadores promissores para processos de fotossíntese artificial, porém até o momento não há um material de consenso como fotocatalisador ideal para a redução de CO2. Entre os utilizados com essa finalidade, o Nb2O5 é uma alternativa promissora, uma vez que possui características promissoras à catálise, como grupos de superfície capazes de auxiliar em processos catalíticos e alta estabilidade química. No entanto, sua capacidade de absorver somente radiação UV torna seu uso em larga escala, utilizando a radiação solar, um processo pouco eficiente. Portanto nesta tese foi investigada uma alternativa para melhorar as características do Nb2O5 como fotocatalisador, através da formação de heterojunções com o C3N4, um semicondutor que absorve abaixo de 460 nm do espectro visível. Inicialmente, observou-se a capacidade do Nb2O5 em fotocatalisar a reação de conversão de CO2 em produtos C1 e C2, dado que óxidos de nióbio de um modo geral possuem elevada acidez superficial, fator que poderia diminuir a interação entre o CO2 e a superfície do catalisador. No entanto observou-se que a acidez superficial do Nb2O5 o tornou em catalisador preferencial para formação de CO, devido à baixa interação dessa molécula com a superfície do catalisador. Com isso, observou-se que o Nb2O5 é um possível agente catalisador de reações de fotoredução de CO2. Após verificar as principais características do Nb2O5, buscou-se alternativas para formar heterojunções entre o Nb2O5 e o g-C3N4, tanto para aumentar sua absorção do espectro eletromagnético, quanto para aumentar sua performance fotocatalítica. Para tal optou-se pela heteroagregação sonoquímica induzida pela diferença de carga superficial. Esse método se mostrou eficiente e capaz de formar heteroestruturas g-C3N4/Nb2O5, onde as partículas de Nb2O5 foram homogeneamente dispersas sob a superfície do g-C3N4, conferindo assim um intimo contato entre as partículas, elevado compartilhamento das cargas fotogeradas e consequentemente uma alta atividade fotocatalítica tanto para degradação de poluentes orgânicos, quanto para conversão de CO2 em CH4.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES: código de financiamento - 001engUniversidade Federal de São CarlosCâmpus São CarlosPrograma de Pós-Graduação em Química - PPGQUFSCarAttribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/info:eu-repo/semantics/openAccessSemicondutoresHeteroestruturasConversão de CO2Nitreto de carbonoFotoreduçãoFotossíntese artificialCIENCIAS EXATAS E DA TERRA::QUIMICASynthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic propertiesSíntese de heteroestruturas g-C3N4/Nb2O5: estudo das propriedades fotocatalíticasinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis60060019447b82-be97-4aec-a6e8-de69229cbfdereponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALTese_GTSTS.pdfTese_GTSTS.pdfTeseapplication/pdf14092296https://repositorio.ufscar.br/bitstream/ufscar/12198/1/Tese_GTSTS.pdf5b2cb52aa5df8d0d2885874c09189d84MD51Comprovante.pdfComprovante.pdfCarta de comprovante da versão final da teseapplication/pdf83931https://repositorio.ufscar.br/bitstream/ufscar/12198/2/Comprovante.pdfc09833a91ae2a26456adbae4cf442103MD52CC-LICENSElicense_rdflicense_rdfapplication/rdf+xml; charset=utf-8811https://repositorio.ufscar.br/bitstream/ufscar/12198/3/license_rdfe39d27027a6cc9cb039ad269a5db8e34MD53TEXTTese_GTSTS.pdf.txtTese_GTSTS.pdf.txtExtracted texttext/plain187458https://repositorio.ufscar.br/bitstream/ufscar/12198/4/Tese_GTSTS.pdf.txt071aa5cdc3ffc017189efe44c623e8d6MD54Comprovante.pdf.txtComprovante.pdf.txtExtracted texttext/plain2https://repositorio.ufscar.br/bitstream/ufscar/12198/6/Comprovante.pdf.txtd784fa8b6d98d27699781bd9a7cf19f0MD56THUMBNAILTese_GTSTS.pdf.jpgTese_GTSTS.pdf.jpgIM Thumbnailimage/jpeg9569https://repositorio.ufscar.br/bitstream/ufscar/12198/5/Tese_GTSTS.pdf.jpg58dd19690d3d335c647422d0d968e21cMD55Comprovante.pdf.jpgComprovante.pdf.jpgIM Thumbnailimage/jpeg11927https://repositorio.ufscar.br/bitstream/ufscar/12198/7/Comprovante.pdf.jpgccc1066112873331b0ac031b62108c0cMD57ufscar/121982023-09-18 18:31:56.79oai:repositorio.ufscar.br:ufscar/12198Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:56Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.eng.fl_str_mv |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
dc.title.alternative.por.fl_str_mv |
Síntese de heteroestruturas g-C3N4/Nb2O5: estudo das propriedades fotocatalíticas |
title |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
spellingShingle |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties Silva, Gelson Tiago dos Santos Tavares da Semicondutores Heteroestruturas Conversão de CO2 Nitreto de carbono Fotoredução Fotossíntese artificial CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
title_full |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
title_fullStr |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
title_full_unstemmed |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
title_sort |
Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties |
author |
Silva, Gelson Tiago dos Santos Tavares da |
author_facet |
Silva, Gelson Tiago dos Santos Tavares da |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/1463546552427589 |
dc.contributor.author.fl_str_mv |
Silva, Gelson Tiago dos Santos Tavares da |
dc.contributor.advisor1.fl_str_mv |
Oliveira, Cauê Ribeiro de |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/5321313558714462 |
dc.contributor.advisor-co1.fl_str_mv |
Paris, Elaine Cristina |
dc.contributor.advisor-co1Lattes.fl_str_mv |
http://lattes.cnpq.br/8475640212486290 |
dc.contributor.authorID.fl_str_mv |
09d1e4a7-99e5-48be-b961-68781e978b9c |
contributor_str_mv |
Oliveira, Cauê Ribeiro de Paris, Elaine Cristina |
dc.subject.por.fl_str_mv |
Semicondutores Heteroestruturas Conversão de CO2 Nitreto de carbono Fotoredução Fotossíntese artificial |
topic |
Semicondutores Heteroestruturas Conversão de CO2 Nitreto de carbono Fotoredução Fotossíntese artificial CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
Semiconductors are promising catalysts for artificial photosynthesis, but to date, there is no consensus on the ideal photocatalyst for CO2 reduction. Among semiconductors used for CO2 reduction, Nb2O5 is a promising alternative, since it has characteristics useful for catalysis, such as surface groups capable of assisting catalytic processes and high chemical stability. However, Nb2O5 absorbs only UV radiation, thus large-scale application of the same under solar radiation is inefficient. Given this problem, the formation of heterojunctions between Nb2O5 and C3N4, a semiconductor that absorbs below 460 nm of the visible spectrum, was investigated in this thesis as an alternative method to improve the photocatalytic properties of Nb2O5. Initially, the ability of Nb2O5 to convert CO2 in C1 and C2 products under irradiation was studied since Nb2O5 is known for its high surface acidity, a factor that could decrease the interaction of CO2 with the surface of the catalyst. However, it was observed that the surface acidity of Nb2O5 favored the formation of CO due to the low interaction of this molecule with the surface of the catalyst. This finding showed that Nb2O5 is a possible catalyst for CO2 photoreduction reactions. Accordingly, the main characteristics of Nb2O5 was verified and alternative synthesis methods for the formation of heterojunctions between Nb2O5 and g-C3N4 were investigated in order to shift the absorption of Nb2O5 into the visible region and increase its photocatalytic performance. To that end, heteroaggregation induced by difference in superficial charge was chosen. The method proved efficient for the formation of g-C3N4/Nb2O5 heterostructures, where the Nb2O5 particles were homogeneously dispersed on the surface of g-C3N4, thus conferring an intimate contact between the particles, high sharing of photogenerated charges, and consequently high photocatalytic activity for the degradation of organic pollutants and conversion of CO2 into CH4. |
publishDate |
2019 |
dc.date.issued.fl_str_mv |
2019-04-22 |
dc.date.accessioned.fl_str_mv |
2020-01-30T18:14:39Z |
dc.date.available.fl_str_mv |
2020-01-30T18:14:39Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
SILVA, Gelson Tiago dos Santos Tavares da. Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties. 2019. Tese (Doutorado em Química) – Universidade Federal de São Carlos, São Carlos, 2019. Disponível em: https://repositorio.ufscar.br/handle/ufscar/12198. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/12198 |
identifier_str_mv |
SILVA, Gelson Tiago dos Santos Tavares da. Synthesis of g-C3N4/Nb2O5 heterostructures: study of photocatalytic properties. 2019. Tese (Doutorado em Química) – Universidade Federal de São Carlos, São Carlos, 2019. Disponível em: https://repositorio.ufscar.br/handle/ufscar/12198. |
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https://repositorio.ufscar.br/handle/ufscar/12198 |
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Universidade Federal de São Carlos Câmpus São Carlos |
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Programa de Pós-Graduação em Química - PPGQ |
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UFSCar |
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Universidade Federal de São Carlos Câmpus São Carlos |
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