Electrochemical properties of benzylmercapto and dodecylmercapto tetra substituted nickel phthalocyanine complexes: Electrocatalytic oxidation of nitrite

Agboola, B. and Ozoemena, K.I. and Nyokong, T. (2006) Electrochemical properties of benzylmercapto and dodecylmercapto tetra substituted nickel phthalocyanine complexes: Electrocatalytic oxidation of nitrite. Electrochimica Acta, 51 (28). pp. 6470-6478. ISSN 0013-4686

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Official URL: http://dx.doi.org/10.1016/j.electacta.2006.04.033

Abstract

Nickel tetrakis(benzylmercapto)phthalocyanine (NiTBMPc) and nickel tetrakis(dodecylmercapto)phthalocyanine (NiTDMPc) complexes were synthesized and their spectral and electrochemical properties reported. The CV showed four or five redox processes for NiTBMPc and NiTDMPc, respectively. For the first time, spectroelectrochemistry gave evidence for the formation of Ni[superscript II]/Ni[superscrpt I] process in a NiPc complex. The rest of the processes were ring based. The NiTBMPc complex was successfully deposited on both gold and glassy carbon electrodes by electropolymerisation while NiTDMPc complex was deposited on gold electrode only. The films were electro-transformed in aqueous 0.1 M NaOH solution to the O–Ni–O oxo bridged form. The modified electrodes were characterized using electrochemical impedance spectroscopy and the results showed typical behavior for modified electrodes. Electrodes with poly-Ni(OH)Pcs films exhibited higher charge transfer resistance values, Rp than their corresponding poly-NiPcs films counterparts. All the modified electrodes showed improved catalytic activities than the unmodified electrodes towards nitrite ions electrooxidation. Better catalytic activities were observed for the modified electrodes when they were transformed to O–Ni–O oxo bridge form. All the modified electrodes exhibited high resistance to electrode surface passivation.

Item Type:Article
Additional Information:Corresponding author. Kenneth Ozoemena. Tel.: +27 12 420 2515; fax: +27 12 362 5297. E-Mail kenneth.ozoemena@up.ac.za
Uncontrolled Keywords:Nickel phthalocyanine; Cyclic voltammetry; Electropolymerisation; Electrochemical impedance spectroscopy; Electrocatalysis; Nitrite oxidation
Subjects:Y Unknown > Subjects to be assigned
Divisions:Faculty > Faculty of Science > Chemistry
ID Code:427
Deposited By: Mrs Eileen Shepherd
Deposited On:31 Oct 2006
Last Modified:06 Jan 2012 16:18
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