Electrospun iron-polyaniline-polyacrylonitrile derived nanofibers as non-precious oxygen reduction reaction catalysts for PEM fuel cells

Replacing high cost platinum (Pt) catalysts with alternative non-precious materials for the oxygen reduction reaction (ORR) is highly desirable to reduce the cost of polymer electrolyte membrane fuel cell (PEMFC) systems. Transition metal-nitrogen-carbon complexes (M-N-C) prepared by high temperature heat treatment techniques are the most promising class of non-precious materials with respect to ORR activity and stability. In this work, one-dimensional nanofibers are prepared by electrospinning an iron-polyaniline/polyacrylonitrile (Fe-PANI-PAN) metal-polymer blend, followed by subsequent heat treatment. This represents the first time a blend of polymers (PANI-PAN) has been used to prepare M-N-C nanofiber catalysts via electrospinning. The addition of 10 wt. % PANI to the electrospinning mixture provides 100 and 70 mV improvements to the ORR onset potential and half-wave potential, respectively, rendering the most active non-precious ORR nanofiber catalysts prepared by electrospinning to date. The high activity is attributed to the porous structure of the nanofibers, combined with increased nitrogen contents provided by the PANI incorporation.