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Porphyrin Nanorods Modified Glassy Carbon Electrode for the Electrocatalysis of Dioxygen, Methanol and Hydrazine
Author(s) -
C.George Reama,
Mugadza Tawanda,
Khene Samson,
Egharevba Gabriel O.,
Nyokong Tebello
Publication year - 2011
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201100081
Subject(s) - porphyrin , nanorod , electrocatalyst , electrochemistry , chemistry , glassy carbon , hydrazine (antidepressant) , inorganic chemistry , methanol , oxidizing agent , photochemistry , cyclic voltammetry , electrode , materials science , organic chemistry , nanotechnology , chromatography
Porphyrin nanorods (PNR) were prepared by ionic self‐assembly of two oppositely charged porphyrin molecules consisting of free base meso ‐tetraphenylsulfonate porphyrin (H 4 TPPS 4 2− ) and meso ‐tetra( N ‐methyl‐4‐pyridyl) porphyrin (MTMePyP 4+ M=Sn, Mn, In, Co). These consist of H 4 TPPS 4 2− SnTMePyP 4+ , H 4 TPPS 4 2− CoTMePyP 4+ , H 4 TPPS 4 2− InTMePyP 4+ and H 4 TPPS 4 2− MnTMePyP 4+ porphyrin nanorods. The absorption spectra and transmission electron microscopic (TEM) images of these structures were obtained. These porphyrin nanostructures were used to modify a glassy carbon electrode for the electrocatalytic reduction of oxygen, and the oxidation of hydrazine and methanol at low pH. The cyclic voltammogram of PNR‐modified GCE in pH 2 buffer solution has five irreversible processes, two distinct reduction processes and three oxidation processes. The porphyrin nanorods modified GCE produce good responses especially towards oxygen reduction at −0.50 V vs. Ag|AgCl (3 M KCl). The process of electrocatalytic oxidation of methanol using PNR‐modified GCE begins at 0.71 V vs. Ag|AgCl (3 M KCl). The electrochemical oxidation of hydrazine began at around 0.36 V on H 4 TPPS 4 2− SnTMePyP 4+ modified GCE. The GCE modified with H 4 TPPS 4 2− CoTMePyP 4+ H 4 TPPS 4 2− InTMePyP 4+ and H 4 TPPS 4 2− MnTMePyP 4+ porphyrin nanorods began oxidizing hydrazine at 0.54 V, 0.59 V and 0.56 V, respectively.