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Carbon nanotubes as catalysts for wet peroxide oxidation: the effect of surface chemistry

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dc.contributor.authorMartin-Martinez, Maria
dc.contributor.authorMachado, Bruno
dc.contributor.authorSerp, Philippe
dc.contributor.authorMorales-Torres, Sergio
dc.contributor.authorSilva, Adrián
dc.contributor.authorFigueiredo, José
dc.contributor.authorFaria, Joaquim
dc.contributor.authorGomes, Helder
dc.date.accessioned2020-12-03T09:48:45Z
dc.date.available2020-12-03T09:48:45Z
dc.date.issued2020
dc.description.abstractThree magnetic carbon nanotube (CNT) samples, named A30 (N-doped), E30 (undoped) and E10A20 (selectively N-doped), synthesized by catalytic chemical vapor deposition, were modified by introducing oxygenated surface groups (oxidation with HNO3, samples CNT-N), and by heat treatment at 800 °C for the removal of surface functionalities (samples CNT-HT). Both treatments lead to higher specific surface areas. The acid treatment results in more acidic surfaces, with higher amounts of oxygenated species being introduced on Ndoped surfaces. Heat-treated samples are less hydrophilic than those treated with nitric acid, heat treatment leading to neutral or basic surfaces, only N-quaternary and N-pyridinic species being found by XPS on N-doped surfaces. These materials were tested in the catalytic wet peroxide oxidation (CWPO) of highly concentrated 4-nitrophenol solutions (4-NP, 5 g L−1) at atmospheric pressure, T=50 °C and pH=3, using a catalyst load of 2.5 g L−1 and the stoichiometric amount of H2O2 needed for the complete mineralization of 4-NP. The high temperature treatment enhanced significantly the activity of the CNTs towards CWPO, evaluated in terms of 4-NP and total organic carbon conversion, due to the increased hydrophobicity of their surface. In particular, E30HT and E10A20HT were able to remove ca. 100% of 4-NP after 8 h of operation. On the other hand, by treating the CNTs with HNO3, the activity of the less hydrophilic samples decreased upon increasing the concentration of surface oxygen-containing functionalities, whilst the reactivity generated inside the opened nanotubes improved the activity of the highly hydrophilic A30 N.pt_PT
dc.description.sponsorshipThis work is a result of project “AIProcMat@N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006, supported by NORTE 2020, under the Portugal 2020 Partnership Agreement, through the ERDF and of Project Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC). M. Martín Martínez acknowledges the postdoc grant 2017-T2/AMB-5668 from Comunidad de Madrid, Programme “Atracción de talento investigador”. B. Machado acknowledges the exploratory project under FCT Investigator Programme (ref. IF/00301/ 2015) with the financial support of FCT/MCTES through national funds (PIDDAC). S. Morales Torres acknowledges the financial support from University of Granada (Reincorporación Plan Propio).pt_PT
dc.description.versioninfo:eu-repo/semantics/publishedVersionpt_PT
dc.identifier.citationMartin-Martinez, Maria; Machado, Bruno F.; Serp, Philippe; Morales-Torres, Sergio; Silva, Adrián; Figueiredo, José L.; Faria, Joaquim L.; Gomes, Helder (2020). Carbon nanotubes as catalysts for wet peroxide oxidation: the effect of surface chemistry. Catalysis Today . ISSN 0920-5861. 357, p. 332-340pt_PT
dc.identifier.doi10.1016/j.cattod.2019.03.014pt_PT
dc.identifier.issn0920-5861
dc.identifier.urihttp://hdl.handle.net/10198/22916
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.rights.urihttp://creativecommons.org/licenses/by-nc/4.0/pt_PT
dc.subjectCarbon nanotubespt_PT
dc.subjectSurface modificationpt_PT
dc.subjectCWPOpt_PT
dc.subject4-Nitrophenolpt_PT
dc.titleCarbon nanotubes as catalysts for wet peroxide oxidation: the effect of surface chemistrypt_PT
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage340pt_PT
oaire.citation.startPage332pt_PT
oaire.citation.titleCatalysis Todaypt_PT
oaire.citation.volume357pt_PT
person.familyNameGomes
person.givenNameHelder
person.identifier.ciencia-id6218-1E19-13EE
person.identifier.orcid0000-0001-6898-2408
rcaap.rightsrestrictedAccesspt_PT
rcaap.typearticlept_PT
relation.isAuthorOfPublication0eb96337-224a-4339-9918-334436fbbb99
relation.isAuthorOfPublication.latestForDiscovery0eb96337-224a-4339-9918-334436fbbb99

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