Iridium-decorated Palladium–Platinum core–shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell

Abstract

Carbon-supported Pt, Pd, Pd–Pt core–shell (Ptshell–Pdcore/C) and Ir-decorated Pd–Pt core–shell (Ir-decorated Ptshell–Pdcore/C) catalysts were synthesized, and their physical properties, electrochemical behaviors, oxygen reduction reaction (ORR) characteristics and proton exchange membrane fuel cell (PEMFC) performances were investigated herein. From the XRD patterns and TEM images, Ir-decorated Ptshell–Pdcore/C has been confirmed that Pt was deposited on the Pd nanoparticle which had the core–shell structure. Ir-decorated Ptshell–Pdcore/C has more positive OH reduction peak than Pt/C, which is beneficial to weaken the binding energy of Pt–OH during the ORR. Thus, Ir-decorated Ptshell–Pdcore/C has higher ORR activity than Pt/C. The maximum power density of H2–O2 PEMFC using Ir-decorated Ptshell–Pdcore/C is 792.2mWcm−2 at 70°C, which is 24% higher than that using Pt/C. The single-cell accelerated degradation test of PEMFC using Ir-decorated Ptshell–Pdcore/C shows good durability by the potential cycling of 40,000 cycles. This study concludes that Ir-decorated Ptshell–Pdcore/C has the low Pt content, but it can facilitate the low-cost and high-efficient PEMFC.