Ozoemena K.I., Mamuru S.A., Fukuda T., Kobayashi N., Nyokong T.
Energy and Processes, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Miering Naude Road, Pretoria 0001, South Africa; Department of Chemistry, University of Pretoria, Pretoria, 0002, South Africa; Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan; Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa
Ozoemena, K.I., Energy and Processes, Materials Science and Manufacturing, Council for Scientific and Industrial Research (CSIR), Miering Naude Road, Pretoria 0001, South Africa, Department of Chemistry, University of Pretoria, Pretoria, 0002, South Africa; Mamuru, S.A., Department of Chemistry, University of Pretoria, Pretoria, 0002, South Africa; Fukuda, T., Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan; Kobayashi, N., Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan; Nyokong, T., Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa
Novel hexabutylsulphonyltribenzotetraazachlorin-fullerene (C60) complexes of iron (FeHBSTBTAC-C60) and cobalt (CoHBSTBTAC-C60) have been synthesized and their electrochemistry and oxygen reduction reaction (ORR) compared with their octabutylsulphonylphthalocyanine analogues (FeOBSPc and CoOBSPc). It is proved that electron-withdrawing substituents (-SO2Bu and C60) on phthalocyanine macrocycle exhibit distinct impact on the solution electrochemistry of these metallophthalocyanine (MPc) complexes. The more electron-withdrawing C60 substituent suppressed ORR compared to the -SO2Bu in alkaline medium. FeOBSPc showed the best ORR activity involving a direct 4-electron mechanism, a rate constant of ∼1 × 108 cm3 mol-1 s-1 and a Tafel slope of -171 mV dec-1. © 2009 Elsevier B.V. All rights reserved.
Alkaline medium; Electron mechanism; Electron-withdrawing substituents; Electronwithdrawing; Metallophthalocyanine; Oxygen reduction; Oxygen reduction reaction; Phthalocyanine macrocycle; RDE experiment; Tafel slopes; Cobalt; Electrochemistry; Electrolytic reduction; Fullerenes; Iron compounds; Oxygen; Rate constants; Cyclic voltammetry