Performance, methanol tolerance and stability of Fe-aminobenzimidazole derived catalyst for direct methanol fuel cells

Highly active and durable non-platinum group metals (non-PGM) catalyst based on iron-nitrogen-carbon (Fe-N-C) for the oxygen reduction reaction (ORR) derived from pyrolyzed Fe-aminobenzimidazole (Fe-ABZIM) was synthesized by sacrificial support method (SSM), and characterized by several physical chemical techniques: scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller method and X-ray photoelectron spectroscopy. In half-cell electrochemical configuration, the Fe-ABZIM catalyst presented a significant improvement of ORR activity with respect to a recently reported non-PGM formulation based on Fe-aminoantipyrine, with an enhancement of half wave potential of about 85 mV in O-2-saturated sulfuric acid solution. To the moment, the gap with respect to a benchmark Pt/C catalyst was about 90 mV. The Fe-ABZIM catalyst showed a remarkably high tolerance to methanol, resulting in superior ORR performance compared to Pt/C at methanol concentrations higher than 0.02 M. In direct methanol fuel cell (DMFC) good performances were also obtained. A durability test (100 h) at 90 degrees C, feeding 5 M methanol, was carried out. A certain decrease of performance was recorded, amounting to -0.20 mW cm(-2) h(-1) at the very beginning of test and -0.05 mW cm(-2) h(-1) at the end. However, the Fe-ABZIM is more adequate than previously reported formulations in terms of both ORR activity and stability. (C) 2016 Elsevier B.V. All rights reserved.