Graphene-Polyaniline Nanofiber Composite as Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media

摘要

Here, we report a novel, cost effective, metal free electrocatalyst for oxygen reduction reaction. Graphene nanosheet (GNS) -polyaniline (PANI) nanofiber composite was prepared by simple chemical route using pre-synthesized GNS and PANI nanofibers. The GNS-PANI nanocomposite exhibited better electrochemical performance compared to GNS alone. The structural and morphological features of this composite were examined by microscopy, spectroscopy and electro-analytical techniques. The results confirmed that PANI nanofibers are homogeneously dispersed as well as interconnected with the GNS. This characteristic feature significantly enhances the charge transfer reactions at the interface. GNS-PANI nanocomposite modified glassy carbon (GC) electrode exhibited finite onset potential for oxygen reduction reaction with a 100 mV positive shift compared to GNS modified GC electrode in alkaline electrolyte. Koutecky-Levich (K-L) plot analysis revealed that the oxygen reduction reaction proceed virtually via 4 electron pathway. Thus, the present GNS-PANI nanocomposite may be a promising cathode material for fuel cell applications.