An efficient ultrathin PtFeNi nanowire/ionic liquid conjugate electrocatalyst

Abstract

Boosting the rate of oxygen reduction reaction (ORR) on Pt surface is essential to the commercialization of proton exchange membrane fuel cells (PEMFCs), which has thus stimulated tremendous efforts in pursuing the optimized oxygen adsorption strength and maximizing the Pt utilization regarding the composition, architecture and surface geometry. Further activity enhancement necessitates strategies other than solely inner/surface tuning of metallic nanocrystals, which yet remains scarce. Applying ultrathin PtFeNi trimetallic nanowires (NWs) as the model catalyst, we herein demonstrate the PtFeNi/ionic liquid (IL) conjugate system can greatly boost the ORR rate on Pt surface. The IL conjugated ultrathin PtFeNi NWs (IL/PtFeNi NWs) achieves an impressive mass activity of 2.83 A mg−1Pt, which is 1.72 and 15.5 times higher than the PtFeNi NWs and benchmark Pt/C, respectively. Furthermore, the IL conjugation also improved the durability during the accelerated stability tests when compared to the non-conjugated counterpart. The combination of experimental characterizations and theoretical calculations reveal that the enhanced catalytic performance derives from the IL-induced flexible electronic layer for even modification of the surface activity. The ultrathin IL/PtFeNi interface NWs also show the remarkable performances towards the electro-oxidation of methanol and the H2O2 detection. The present interfacial engineering strategy offers a new opportunity to realize further electrocatalytic activity enhancements for future renewable energy applications.