Surface Chemistry in the Process of Coating Mesoporous SiO2 onto Carbon Nanotubes Driven by the Formation of Si-O-C Bonds

dc.creatorPaula, AJ
dc.creatorStefani, D
dc.creatorSouza, AG
dc.creatorKim, YA
dc.creatorEndo, M
dc.creatorAlves, OL
dc.date2011
dc.dateMAR
dc.date2014-07-30T20:07:11Z
dc.date2015-11-26T16:58:04Z
dc.date2014-07-30T20:07:11Z
dc.date2015-11-26T16:58:04Z
dc.date.accessioned2018-03-28T23:45:41Z
dc.date.available2018-03-28T23:45:41Z
dc.identifierChemistry-a European Journal. Wiley-blackwell, v. 17, n. 11, n. 3228, n. 3237, 2011.
dc.identifier0947-6539
dc.identifierWOS:000288098800024
dc.identifier10.1002/chem.201002455
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/74860
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/74860
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1277837
dc.descriptionConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.descriptionThe deposition of mesoporous silica (SiO2) on carbon nanotubes (CNTs) has opened up a wide range of assembling possibilities by exploiting the sidewall of CNTs and organosilane chemistry. The resulting systems may be suitable for applications in catalysis, energy conversion, environmental chemistry, and nanomedicine. However, to promote the condensation of silicon monomers on the nanotube without producing segregated particles, (OR)(4-x)SiOxx- units must undergo nucleophilic substitution by groups localized on the CNT sidewall during the transesterification reaction. In order to achieve this preferential attachment, we have deposited silica on oxidized carbon nanotubes (single-walled and multiwalled) in a sol-gel process that also involved the use of a soft template (cetyltrimethylammonium bromide, CTAB). In contrast to the simple approach normally used to describe the attachment of inorganic compounds on CNTs, SiO2 nucleation on the tube is a result of nucleophilic attack mainly by hydroxyl radicals, localized in a very complex surface chemical environment, where various oxygenated groups are covalently bonded to the sidewall and carboxylated carbonaceous fragments (CCFs) are adsorbed on the tubes. Si-O-C covalent bond formation in the SiO2-CNT hybrids was observed even after removal of the CCFs with sodium hydroxide. By adding CTAB, and increasing the temperature, time, and initial amount of the catalyst (NH4OH) in the synthesis, the SiO2 coating morphology could be changed from one of nanoparticles to mesoporous shells. Concomitantly, pore ordering was achieved by increasing the amount of CTAB. Furthermore, preferential attachment on the sidewall results mostly in CNTs with uncapped ends, having sites (carboxylic acids) that can be used for further localized reactions.
dc.description17
dc.description11
dc.description3228
dc.description3237
dc.descriptionConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.descriptionRegional Innovation Cluster Program of Nagano
dc.descriptionMinistry of Education, Culture, Sports, Science and Technology of Japan [19002007, 20510096]
dc.descriptionConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.descriptionCNPq [306335/2007-7, 503956/2007-4, 577489/2008-9]
dc.descriptionMinistry of Education, Culture, Sports, Science and Technology of Japan [19002007, 20510096]
dc.languageen
dc.publisherWiley-blackwell
dc.publisherMalden
dc.publisherEUA
dc.relationChemistry-a European Journal
dc.relationChem.-Eur. J.
dc.rightsfechado
dc.rightshttp://olabout.wiley.com/WileyCDA/Section/id-406071.html
dc.sourceWeb of Science
dc.subjectcarbon nanotubes
dc.subjectmesoporous materials
dc.subjectnanomaterials
dc.subjectsol-gel processes
dc.subjectsurface chemistry
dc.subjectSilica Nanoparticles
dc.subjectSidewall Functionalization
dc.subjectSingle
dc.subjectNanocomposites
dc.subjectPurification
dc.subjectTemperature
dc.subjectSensitivity
dc.subjectAttachment
dc.subjectTemplates
dc.subjectOxidation
dc.titleSurface Chemistry in the Process of Coating Mesoporous SiO2 onto Carbon Nanotubes Driven by the Formation of Si-O-C Bonds
dc.typeArtículos de revistas


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