Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H2 and Ar as carrier gases

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dc.citation.doi10.1039/c7ra03142den_ZA
dc.citation.epage21195en_ZA
dc.citation.issue34en_ZA
dc.citation.spage21187en_ZA
dc.contributor.authorMutuma, B.K.
dc.contributor.authorMatsoso, B.J.
dc.contributor.authorRanganathan, K.
dc.contributor.authorWamwangi, D.
dc.contributor.authorCoville, N.J
dc.contributor.authorKeartland, J.
dc.date.accessioned2018-01-19T13:55:06Z
dc.date.available2018-01-19T13:55:06Z
dc.date.issued2017
dc.description.abstractSolid carbon spheres (CSs, d ≈ 200 nm) were synthesized (yield, <40%) in a vertically oriented chemical vapor deposition (CVD) reactor using acetylene as a carbon source and Ar or H2 as the carrier gas. The CSs synthesized in the presence of H2 exhibited a broader thermal gravimetric derivative curve and a narrower paramagnetic signal than the CSs synthesized in Ar. Post synthesis doping of both types of CSs with nitrogen was achieved by passing acetonitrile at 800 °C for 1 h over the CSs in a CVD reactor. The N-doped CSs (NCSs) synthesized under both H2 and Ar displayed an increase in ID/IG ratios as obtained from Raman spectroscopy and showed an increase in the paramagnetic signal due to the presence of nitrogen induced defects compared to the undoped CSs. The NCSs synthesized in H2 had less graphitic-N (22%) than those produced in Ar (50%). The presence of a higher percentage of pyridinic-N and pyrrolic-N for the NCSs prepared with H2 as carrier gas suggested H2 etching effects on the CSs. Further, the N-doped carbon spheres obtained in the presence of H2 gave a higher N/C ratio (5.0) than in the presence of Ar (3.7). The introduction of edge defects and paramagnetic centers in CSs in the presence of H2 gas without the aid of a metal catalyst opens up a platform for regulating surface and catalytic reactions of CSsen_ZA
dc.description.librarianEM2017en_ZA
dc.funderNational Research Foundationen_ZA
dc.identifier.citationMutuma, B.K. et al. Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H2 and Ar as carrier gases. RSC ADVANCES 7(34), 2017, pp. 21187-21195en_ZA
dc.identifier.issn2046-2069 (Online)
dc.identifier.urihttp://hdl.handle.net/10539/23730
dc.journal.titleRSC ADVANCESen_ZA
dc.journal.volume7en_ZA
dc.language.isoenen_ZA
dc.publisherRoyal Society of Chemistryen_ZA
dc.rights© 2017. The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported License.en_ZA
dc.subjectCatalysisen_ZA
dc.subjectCatalystsen_ZA
dc.subjectDoping (additives)en_ZA
dc.subjectNitrogenen_ZA
dc.subjectParamagnetismen_ZA
dc.subjectSpheresen_ZA
dc.subjectSurface defectsen_ZA
dc.subjectSurface reactionsen_ZA
dc.subjectCatalytic reactionsen_ZA
dc.subjectChemical vapor deposition reactorsen_ZA
dc.subjectInduced defectsen_ZA
dc.subjectMetal catalysten_ZA
dc.subjectParamagnetic centersen_ZA
dc.subjectParamagnetic signalsen_ZA
dc.subjectRadical speciesen_ZA
dc.subjectThermal gravimetricen_ZA
dc.subjectChemical vapor depositionen_ZA
dc.subjectELECTRON-SPIN-RESONANCEen_ZA
dc.subjectNITROGEN-CONTAINING CARBONen_ZA
dc.subjectONE-STEP SYNTHESISen_ZA
dc.subjectAMORPHOUS-CARBONen_ZA
dc.subjectTHIN-FILMSen_ZA
dc.subjectHYDROGENATED CARBONen_ZA
dc.subjectNANOTUBESen_ZA
dc.subjectGRAPHENEen_ZA
dc.titleGeneration of radical species in CVD grown pristine and N-doped solid carbon spheres using H2 and Ar as carrier gasesen_ZA
dc.typeArticleen_ZA
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