Ultrathin IrRu nanowire networks with high performance and durability for the hydrogen oxidation reaction in alkaline anion exchange membrane fuel cells

Abstract

Developing highly active and stable HOR catalysts still remains a challenging task for alkaline anion exchange membrane fuel cells. A carbon supported IrRu nanowire catalyst with different compositions was prepared by a soft template method, involving the chemical reduction of iridium and ruthenium complexes using sodium borohydride. The Ir₁Ru₁ ultrathin nanowires exhibit higher hydrogen oxidation activity and better stability under alkaline conditions in comparison with commercial Pt/C. An electrochemical test demonstrates that the mass and specific activities at an over potential of 50 mV of Ir₁Ru₁ NWs/C are 4.2 and 3.8 times that of commercial Pt/C, respectively. Furthermore, the synthesized Ir₁Ru₁ NWs display better stability against potential cycling due to their unique interconnected structure. After 2000 potential cycles, the electrochemically active surface area (ECSA) of Ir₁Ru₁ NWs/C reduces only by 2.27%, and the mass activity@50 mV is reduced by 8.21%. The single cell used the as-prepared Ir₁Ru₁ NWs/C as the anode catalyst and Pt/C as the cathode catalyst, and the AAEMFC shows a peak power density of more than 485 mW cm⁻², which is about 1.66 fold that of the AAEMFC using commercial Pt/C as the anode catalyst (292 mW cm⁻²). These results suggest that carbon supported ultrathin Ir₁Ru₁ NW catalysts can be used as substitutes for commercial Pt/C for the HOR in alkaline media for alkaline anion exchange membrane fuel cell application.