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

Show simple item record Mutuma, B.K. Matsoso, B.J. Ranganathan, K. Wamwangi, D. Coville, N.J Keartland, J. 2018-01-19T13:55:06Z 2018-01-19T13:55:06Z 2017
dc.identifier.citation Mutuma, 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. 21187-21195 en_ZA
dc.identifier.issn 2046-2069 (Online)
dc.description.abstract Solid 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 CSs en_ZA
dc.language.iso en en_ZA
dc.publisher Royal Society of Chemistry en_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.subject Catalysis en_ZA
dc.subject Catalysts en_ZA
dc.subject Doping (additives) en_ZA
dc.subject Nitrogen en_ZA
dc.subject Paramagnetism en_ZA
dc.subject Spheres en_ZA
dc.subject Surface defects en_ZA
dc.subject Surface reactions en_ZA
dc.subject Catalytic reactions en_ZA
dc.subject Chemical vapor deposition reactors en_ZA
dc.subject Induced defects en_ZA
dc.subject Metal catalyst en_ZA
dc.subject Paramagnetic centers en_ZA
dc.subject Paramagnetic signals en_ZA
dc.subject Radical species en_ZA
dc.subject Thermal gravimetric en_ZA
dc.subject Chemical vapor deposition en_ZA
dc.subject THIN-FILMS en_ZA
dc.subject NANOTUBES en_ZA
dc.subject GRAPHENE en_ZA
dc.title Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H2 and Ar as carrier gases en_ZA
dc.type Article en_ZA
dc.journal.volume 7 en_ZA
dc.journal.title RSC ADVANCES en_ZA
dc.description.librarian EM2017 en_ZA
dc.citation.doi 10.1039/c7ra03142d en_ZA
dc.citation.epage 21195 en_ZA
dc.citation.issue 34 en_ZA
dc.citation.spage 21187 en_ZA
dc.funder National Research Foundation en_ZA

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