Onion-derived activated carbons with enhanced surface area for improved hydrogen storage and electrochemical energy application

dc.contributor.authorNicholas M. Musyoka
dc.contributor.authorMutuma, B.K. (Bridget)
dc.contributor.authorManyala, Ncholu I.
dc.contributor.emailncholu.manyala@up.ac.zaen_ZA
dc.date.accessioned2021-04-14T10:58:12Z
dc.date.available2021-04-14T10:58:12Z
dc.date.issued2020-07
dc.description.abstractHigh surface area activated carbons (ACs) were prepared from a hydrochar derived from waste onion peels. The resulting ACs had a unique graphene-like nanosheet morphology. The presence of N (0.7%) and O content (8.1%) in the OPAC-800 C was indicative of in situ incorporation of nitrogen groups from the onion peels. The specific surface area and pore volume of the best OPAC sample was found to be 3150 m2 g 1 and 1.64 cm3 g 1, respectively. The hydrogen uptake of all the OPAC samples was established to be above 3 wt% (at 77 K and 1 bar) with the highest being 3.67 wt% (800 C). Additionally, the OPAC- 800 C achieved a specific capacitance of 169 F g 1 at a specific current of 0.5 A g 1 and retained a capacitance of 149 F g 1 at 5 A g 1 in a three electrode system using 3 M KNO3. A symmetric supercapacitor based on the OPAC-800 C//OPAC-800 C electrode provided a capacitance of 158 F g 1 at 0.5 A g 1. The maximum specific energy and power was found to be 14 W h kg 1 and 400 W kg 1, respectively. Moreover, the device exhibited a high coulombic efficiency of 99.85% at 5 A g 1 after 10 000 cycles. The results suggested that the high surface area graphene-like carbon nanostructures are excellent materials for enhanced hydrogen storage and supercapacitor applications.en_ZA
dc.description.departmentPhysicsen_ZA
dc.description.librarianam2021en_ZA
dc.description.sponsorshipThe South Africa's National Research Foundation (NRF) and the South African Research Chairs Initiative (SARChI) of the Department of Science and Innovation.en_ZA
dc.description.urihttp://pubs.rsc.org/en/journals/journalissues/raen_ZA
dc.identifier.citationMusyoka, N.M., Mutuma, B.K. & Manyala, N. Onion-derived activated carbons with enhanced surface area for improved hydrogen storage and electrochemical energy application. RSC Advances, 2020, 10(45): 26928-26936.en_ZA
dc.identifier.issn2046-2069 (online)
dc.identifier.other10.1039/d0ra04556j
dc.identifier.urihttp://hdl.handle.net/2263/79442
dc.language.isoenen_ZA
dc.publisherRoyal Society of Chemistryen_ZA
dc.rights© The Royal Society of Chemistry 2020. This article is licensed under the Creative Commons Attribution License.en_ZA
dc.subjectCarbonsen_ZA
dc.subjectHydrogenen_ZA
dc.subjectEnergyen_ZA
dc.subjectStorageen_ZA
dc.subjectHigh surface area activated carbonsen_ZA
dc.titleOnion-derived activated carbons with enhanced surface area for improved hydrogen storage and electrochemical energy applicationen_ZA
dc.typeArticleen_ZA

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