Methanol tolerant, high performance, noble metal free electrocatalyst developed from polyaniline and ferric chloride for the oxygen reduction reaction

Abstract

The development of low cost oxygen reduction catalysts with improved performance is required for the commercial success of eco-friendly energy conversion systems. Herein, we report a facile and controllable chemical route for the synthesis of porous iron–nitrogen–carbon (Fe–N–C) cathode catalysts for the oxygen reduction reaction (ORR). The catalyst is prepared by pyrolysis of polyaniline (PANI) with ferric chloride in a tubular furnace at 800 °C in an inert atmosphere. The structural and morphological features of the resultant catalysts are fully characterized by spectroscopic and microscopic techniques. The electrocatalytic activities were demonstrated by linear sweep voltammogram (LSV) and chronoamperometric measurements. According to rotating disk electrode (RDE) measurements and Koutecky–Levich analysis, porous Fe–N–C architecture possesses surpassing electrocatalytic activity for ORR via a virtual four electron transfer pathway. Compared to a commercial Pt/C (20 wt% E-Tek) catalyst, the synthesized Fe–N–C catalyst exhibited 25 mV cathodic shift with a close kinetic current density. The present catalyst exhibited methanol tolerance characteristics which are superior to the commercial Pt/C catalyst. This behaviour is reasoned as the existence of numerous active sites of nonporous iron, which are exposed at the catalyst surface with a porous structure of large surface area. Thus, the present Fe–N–C catalyst may be employed as an efficient and inexpensive noble metal-free ORR catalyst for fuel cell applications.