Hierarchically ordered arrays with platinum coated PANI nanowires for highly efficient fuel cell electrodes

The fabrication of a novel electrode architecture with multi-scale orderliness is an effective strategy to enhance Pt utilization and decrease the mass transport polarization loss of proton exchange membrane fuel cells (PEMFCs). Here we report a hierarchically well-defined electrode with Pt nanowhiskers on aligned nanowires by a magnetron sputtering method. With the crystallographically preferential growth of Pt (111) facets, in association with the electron modification effects of PANI on Pt nanowhiskers, the electrode achieves outstanding electrochemical activity towards the oxygen reduction reaction (ORR) with a 2.19-fold enhancement of the specific activity and a similar mass specific activity at 0.9 V (vs. the RHE), compared to the state-of-the-art Pt-C electrode. The PEMFC fabricated with the Pt-PANI-GDL electrode shows excellent performance with a peak power density of 542 mW cm(-2), and a cathode mass specific power density of 5.7 W mg(Pt)(-1), which is 39% greater than that of PEMFCs equipped with a Pt-C electrode for enhanced electrochemical activity and mass transport.