Iron-tetracyanobenzene complex derived non-precious catalyst for oxygen reduction reaction

Non-precious metal oxygen reduction reaction (ORR) catalysts were prepared by pyrolyzing a carbon supported complex consisting of iron acetate coordinated with 1,2,4,5-tetracyanobenzene (TCNB) in an iron phtalocyanine-like polymer arrangement. The effect of heat treatment temperature is systematically investigated from 700 to 1000 degrees C, with ORR activity investigated by half-cell electrochemical evaluation in 0.1 M HClO4. The highest ORR performance is obtained for the sample heat treated at 1000 degrees C, with this sample demonstrating high (>98%) selectivity towards the efficient 4 electron reduction mechanism, comparable with some of the best non-precious metal catalysts reported to date. The physical and surface properties of the prepared catalysts were investigated by high-resolution transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and BET surface area analysis. After heat treatment, a thin (<10 nm) coating was observed on the surface of the carbon supports, attributed to residual species remaining from the heat treated precursor complex that provide the source of ORR activity. (C) 2014 Elsevier Ltd. All rights reserved.