Effects of Redox Mediators on the Catalytic Activity of Iron Porphyrins towards Oxygen Reduction in Acidic Media

He, Qinggang; Wu, Gang; Liu, Ke; Khene, M Samson; Li, Qing; Mugadza, Tawanda; Deunf, Elise; Nyokong, Tebello; Chen, Shaowei W

Title: Effects of Redox Mediators on the Catalytic Activity of Iron Porphyrins towards Oxygen Reduction in Acidic Media
Creator: He, Qinggang
Creator: Wu, Gang
Creator: Liu, Ke
Creator: Khene, M Samson
Creator: Li, Qing
Creator: Mugadza, Tawanda
Creator: Deunf, Elise
Creator: Nyokong, Tebello
Creator: Chen, Shaowei W
Type: Article
Identifier: vital:7291
Identifier: http://hdl.handle.net/10962/d1020354
Description: The effects of different redox mediators on the oxygen reduction reaction (ORR) catalyzed by an iron porphyrin complex, iron(III) meso-tetra(N-methyl-4-pyridyl)porphine chloride [FeIIITMPyP], in 0.1 M triflic acid were investigated by cyclic voltammetry (CV) and spectroelectrochemistry in conjunction with density functional theory (DFT) calculations. The formal potentials of the FeIIITMPyP catalyst and the redox mediators, as well as the half-wave potentials for the ORR, were determined by CV in the absence and presence of oxygen in acidic solutions. UV/Vis spectroscopic and spectroelectrochemical studies confirmed that only the 2,2′-azino-bis(3-ethylbenzothiazioline-6-sulfonic acid)diammonium salt (C18H24N6O6S4) showed effective interactions with FeIIITMPyP during the ORR. DFT calculations suggested strong interaction between FeIIITMPyP and the C18H24N6O6S4 redox mediator. The redox mediator caused lengthening of the dioxygen iron bond, which thus suggested easier dioxygen reduction. Consistent results were observed in electrochemical impedance spectroscopic measurements for which the electron-transfer kinetics were also evaluated.
Description: Original publication is available at http://dx.doi.org/10.1002/celc.201402054
Format: 7 p
Format: pdf
Publisher: Wiley
Language: English
Relation: He, Q., Wu, G., Liu, K., Khene, S., Li, Q., Mugadza, T., Deunf, E., Nyokong, T. & Chen, S. W. 2015. Effects of redox mediators on the catalytic activity of iron porphyrins towards oxygen reduction in acidic media. ChemElectroChem, 1(9):1508–1515. Available: http://dx.doi.org/10.1002/celc.201402054.

Hits: 1147
Visitors: 1138
Downloads: 4

Collections

Khene, Samson Mielie (Assoc Prof)

Nyokong, Tebello (Distinguished Professor)

RU DST/NRF SARChI for Medicinal Chemistry and Nanotechnology

RU Department of Chemistry