Ir3Pb alloy nanodendrites with high performance for ethanol electrooxidation and their enhanced durability by alloying trace Au†
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 mgIr−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-Ir3PbAu0.05/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.