Electrochimica Acta, Vol.76, 430-439, 2012
Synthesis of active iron-based electrocatalyst for the oxygen reduction reaction and its unique electrochemical response in alkaline medium
Efficient iron-based electrocatalyst for the oxygen reduction reaction (ORR) in alkaline medium was synthesized by facilely modifying single-walled carbon nanotubes (SWCNTs) with iron tetrasulfophthalocyanine (FeTSPc). The resulting FeTSPc/SWCNTs composite was characterized by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS). UV-vis absorption spectrum, Fourier transform infrared spectroscopy (FTIR) and Raman spectrum, which confirmed that FeTSPc could be strongly supported onto SWCNTs through pi-pi interaction. Cyclic voltammetry and rotating disk electrode results revealed that the ORR catalyzed by FeTSPc/SWCNTs presented a direct four-electron pathway with a very positive onset potential (+0.05 V vs Ag/AgCI, 3M KCI), cathodic peak potential (-0.10V vs Ag/AgCl. 3M KCI) and a large kinetic rate constant (2.31 x 10(-2)cm s(-1)). Besides, FeTSPc/SWCNTs displayed an even better specificity, long-term stability, tolerance to methanol crossover effect and resistance toward CO poisoning effect than the commercial Pt/C catalyst (40%). Further, the catalytic mechanism of ORR and the unique electrochemical behavior of the active sites in FeTSPc/SWCNTs were also been elucidated. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords:Iron tetrasulfophthalocyanine;Single-walled carbon nanotubes;Electrocatalyst;Oxygen reduction reaction