Pt-based alloy/carbon black nanohybrid covered with ionic liquid supramolecules as an efficient catalyst for oxygen reduction reactions

Abstract

A facile strategy is reported for synthesizing ionic liquid supramolecules (ILSMs) as well as Pt-based alloys on the carbon black surface in a room temperature ionic liquid (1-butyl-3-methylimidazolium bis (tri-fluoromethylsulfonyl) imide) under one atmospheric pressure plasma. The bimetallic PtNi-nanoparticles (NPs) with a size of 2.5-3 nm are stably and uniformly hybridized on the surface of the carbon black, which is covered with a layer of ILSMs. The formation of the developed catalyst is examined using TEM, HAADF-STEM, XRD, TEM-EDS, and TGA measurements. The obtained catalyst exhibits high oxygen reduction reaction (ORR) activity, which is better than those of commercial Pt/C catalysts and Pt/C catalysts prepared without using ionic liquids. This strategy has been extended to fabricate trimetallic PtNiRu-NPs/C nanohybrids with further enhanced activities of up to 2.26 mAcm(-2) and 1.31 Amg(pt)(-1) at 0.9 V versus RHE. The trimetallic PtNiRu-NPs/C catalyst is also more stable than the commercial product under ORR conditions due to the chemical binding of the alloys with the carbon black and the physical stabilization of the nanohybrid materials through the conductive protecting layer of the ILSMs. The results prove that the developed catalysts push the ORR toward completion and can be a promising candidate for numerous electrocatalytic applications. (C) 2016 Elsevier B.V. All rights reserved.