Ir3Pb alloy nanodendrites with high performance for ethanol electrooxidation and their enhanced durability by alloying trace Au

Abstract

In direct ethanol fuel cell technology, the sluggish kinetics of the ethanol oxidation reaction (EOR) at the anode is the main obstacle, and it is thus urgent to develop high performance catalysts. In this work, a new class of porous Ir₃Pb nanodendrites (NDs) was successfully synthesized. The specific activity and mass activity of the synthesized ND-Ir₃Pb/C reach 1.337 mA cm⁻² and 801.1 mA mg_Ir⁻¹, respectively, which are 5.79 and 5.82 times higher than those of the commercial Pt/C-JM. Moreover, the much higher CO₂ selectivity and enhanced durability of ND-Ir₃Pb/C were also evaluated compared to those of the commercial Pt/C-JM. Unexpectedly, we found that the EOR performance, especially the durability and CO₂ selectivity of ND-Ir₃Pb/C can be enhanced dramatically by alloying trace Au (Ir : Au = 3 : 0.05). The specific activity loss of ND-Ir₃PbAu_0.05/C was only 13.9% after 6000 potential cycles, which is much smaller than that of ND-Ir₃Pb/C (34.3%) and Pt/C-JM (53.7%). This study provides a strategic design of efficient Ir-based EOR catalysts for fuel cells.