Pt-Ir-Pd Trimetallic Nanocages as a Dual Catalyst for Efficient Oxygen Reduction and Evolution Reactions in Acidic Media

The development of dual catalysts with high efficiency toward oxygen reduction and evolution reactions (ORR and OER) in acidic media is a significant challenge. Here an active and durable dual catalyst based upon cubic Pt39Ir10Pd11 nanocages with an average edge length of 12.3 nm, porous walls as thin as 1.0 nm, and well-defined {100} facets is reported. The trimetallic nanocages perform better than all the reported dual catalysts in acidic media, with a low ORR-OER overpotential gap of only 704 mV at a Pt-Ir-Pd loading of 16.8 mu g(Pt+Ir+Pd) cm(geo)(-2). For ORR at 0.9 V, when benchmarked against the commercial Pt/C and Pt-Pd nanocages, the trimetallic nanocages exhibit an enhanced mass activity of 0.52 A mg(Pt+Ir+Pd)(-1) (about four and two times as high as those of the Pt/C and Pt-Pd nanocages) and much improved durability. For OER, the trimetallic nanocages show a remarkable mass activity of 0.20 A mg(Pt+Ir)(-1) at 1.53 V, which is 16.7 and 4.3 fold relative to those of the Pt/C and Pt-Pd nanocages, respectively. These improvements can be ascribed to the highly open structure of the nanocages, and the possible electronic coupling between Ir and Pt atoms in the lattice.