“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/31596 |
Resumo: | Although spectroscopic investigation of surface chemisorbed CO2 species has been the focus of most studies, identifying different domains of weakly interacting (physisorbed) CO2 molecules in confined spaces is less trivial as they are often indistinguishable resorting to (isotropic) NMR chemical shift or vibrational band analyses. Herein, we undertake for the first time a thorough solid-state NMR analysis of CO2 species physisorbed prior to and after amine-functionalization of silica surfaces; combining 13C NMR chemical shift anisotropy (CSA) and longitudinal relaxation times (T1). These methods were used to quantitatively distinguish otherwise overlapping physisorbed CO2 signals, which contributed to an empirical model of CO2 speciation for the physi- and chemisorbed fractions. The quantitatively measured T1 values confirm the presence of CO2 molecular dynamics on the microsecond, millisecond, and second time scales, strongly supporting the existence of up to three physisorbed CO2 species with proportions of about 15%, 15%, and 70%, respectively. Our approach takes advantage from using adsorbed 13C-labeled CO2 as probe molecules and quantitative cross-polarization magic-angle spinning to study both physi- and chemisorbed CO2 species, showing that 45% of chemisorbed CO2 versus 55% of physisorbed CO2 is formed from the overall confined CO2 in amine-modified hybrid silicas. A total of six distinct CO2 environments were identified from which three physisorbed CO2 were discriminated, coined here as “gas, liquid, and solid-like” CO2 species. The complex nature of physisorbed CO2 in the presence and absence of chemisorbed CO2 species is revealed, shedding light on what fractions of weakly interacting CO2 are affected upon pore functionalization. This work extends the current knowledge on CO2 sorption mechanisms providing new clues toward CO2 sorbent optimization. |
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“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 speciesCO2 adsorptionSolid-state NMRAmini-modified mesoporous silicaCO2 quantificationChemical shift anisotropyLongitudinal relaxation timeAlthough spectroscopic investigation of surface chemisorbed CO2 species has been the focus of most studies, identifying different domains of weakly interacting (physisorbed) CO2 molecules in confined spaces is less trivial as they are often indistinguishable resorting to (isotropic) NMR chemical shift or vibrational band analyses. Herein, we undertake for the first time a thorough solid-state NMR analysis of CO2 species physisorbed prior to and after amine-functionalization of silica surfaces; combining 13C NMR chemical shift anisotropy (CSA) and longitudinal relaxation times (T1). These methods were used to quantitatively distinguish otherwise overlapping physisorbed CO2 signals, which contributed to an empirical model of CO2 speciation for the physi- and chemisorbed fractions. The quantitatively measured T1 values confirm the presence of CO2 molecular dynamics on the microsecond, millisecond, and second time scales, strongly supporting the existence of up to three physisorbed CO2 species with proportions of about 15%, 15%, and 70%, respectively. Our approach takes advantage from using adsorbed 13C-labeled CO2 as probe molecules and quantitative cross-polarization magic-angle spinning to study both physi- and chemisorbed CO2 species, showing that 45% of chemisorbed CO2 versus 55% of physisorbed CO2 is formed from the overall confined CO2 in amine-modified hybrid silicas. A total of six distinct CO2 environments were identified from which three physisorbed CO2 were discriminated, coined here as “gas, liquid, and solid-like” CO2 species. The complex nature of physisorbed CO2 in the presence and absence of chemisorbed CO2 species is revealed, shedding light on what fractions of weakly interacting CO2 are affected upon pore functionalization. This work extends the current knowledge on CO2 sorption mechanisms providing new clues toward CO2 sorbent optimization.American Chemical Society2021-07-022021-07-02T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfapplication/pdfhttp://hdl.handle.net/10773/31596eng1932-744710.1021/acs.jpcc.1c02871Vieira, RicardoMarin-Montesinos, IldefonsoPereira, JoãoFonseca, RitaIlkaeva, MarinaSardo, MarianaMafra, Luísinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T12:00:52Zoai:ria.ua.pt:10773/31596Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:03:23.200405Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
title |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
spellingShingle |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species Vieira, Ricardo CO2 adsorption Solid-state NMR Amini-modified mesoporous silica CO2 quantification Chemical shift anisotropy Longitudinal relaxation time |
title_short |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
title_full |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
title_fullStr |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
title_full_unstemmed |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
title_sort |
“Hidden” CO2 in amine-modified porous silicas enables full quantitative NMR identification of physi- and chemisorbed CO2 species |
author |
Vieira, Ricardo |
author_facet |
Vieira, Ricardo Marin-Montesinos, Ildefonso Pereira, João Fonseca, Rita Ilkaeva, Marina Sardo, Mariana Mafra, Luís |
author_role |
author |
author2 |
Marin-Montesinos, Ildefonso Pereira, João Fonseca, Rita Ilkaeva, Marina Sardo, Mariana Mafra, Luís |
author2_role |
author author author author author author |
dc.contributor.author.fl_str_mv |
Vieira, Ricardo Marin-Montesinos, Ildefonso Pereira, João Fonseca, Rita Ilkaeva, Marina Sardo, Mariana Mafra, Luís |
dc.subject.por.fl_str_mv |
CO2 adsorption Solid-state NMR Amini-modified mesoporous silica CO2 quantification Chemical shift anisotropy Longitudinal relaxation time |
topic |
CO2 adsorption Solid-state NMR Amini-modified mesoporous silica CO2 quantification Chemical shift anisotropy Longitudinal relaxation time |
description |
Although spectroscopic investigation of surface chemisorbed CO2 species has been the focus of most studies, identifying different domains of weakly interacting (physisorbed) CO2 molecules in confined spaces is less trivial as they are often indistinguishable resorting to (isotropic) NMR chemical shift or vibrational band analyses. Herein, we undertake for the first time a thorough solid-state NMR analysis of CO2 species physisorbed prior to and after amine-functionalization of silica surfaces; combining 13C NMR chemical shift anisotropy (CSA) and longitudinal relaxation times (T1). These methods were used to quantitatively distinguish otherwise overlapping physisorbed CO2 signals, which contributed to an empirical model of CO2 speciation for the physi- and chemisorbed fractions. The quantitatively measured T1 values confirm the presence of CO2 molecular dynamics on the microsecond, millisecond, and second time scales, strongly supporting the existence of up to three physisorbed CO2 species with proportions of about 15%, 15%, and 70%, respectively. Our approach takes advantage from using adsorbed 13C-labeled CO2 as probe molecules and quantitative cross-polarization magic-angle spinning to study both physi- and chemisorbed CO2 species, showing that 45% of chemisorbed CO2 versus 55% of physisorbed CO2 is formed from the overall confined CO2 in amine-modified hybrid silicas. A total of six distinct CO2 environments were identified from which three physisorbed CO2 were discriminated, coined here as “gas, liquid, and solid-like” CO2 species. The complex nature of physisorbed CO2 in the presence and absence of chemisorbed CO2 species is revealed, shedding light on what fractions of weakly interacting CO2 are affected upon pore functionalization. This work extends the current knowledge on CO2 sorption mechanisms providing new clues toward CO2 sorbent optimization. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-07-02 2021-07-02T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10773/31596 |
url |
http://hdl.handle.net/10773/31596 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
1932-7447 10.1021/acs.jpcc.1c02871 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
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1799137689176375296 |