Nitrogen‐Doped Bimetallic Carbide‐Graphite Composite as Highly Active and Extremely Stable Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media
Zaoxue Yan, Yanqi Zhang, Zhifeng Jiang, Deli Jiang, Wei Wei, Zhuofeng Hu
Abstract
Abstract It is demonstrated that nitrogen‐doped bimetallic carbide‐graphite composite (N‐Fe 2 MoC‐GC) has much superior oxygen reduction reaction (ORR) activity to commercial Pt/C with ultrahigh stability, and excellent anti‐methanol and anti‐CO performances. The N‐Fe 2 MoC‐GC has a high initial half‐wave potential of 0.887 V (versus RHE); its mass activity (83 mA mg cat. −1 at 0.9 V versus RHE) is 2.2 times that of Pt/C (40 wt%, 39 mA mg cat. −1 ). In H 2 /O 2 alkaline fuel cell, the N‐Fe 2 MoC‐GC keeps 92.9% of the initial power density (1.12 W cm −2 ) within 70 000 cycles, ranking it as one of the most active and stable noble metal‐free catalysts reported to date. Moreover, the N‐Fe 2 MoC‐GC keeps high power density even under low relative humidity or at high operation temperature. The positive charge on Fe and Mo atoms caused by electron transfer from Fe 2 MoC to N is believed to lead to the excellent ORR activity. The inherent electrochemical stability of the Fe 2 MoC and graphite matrix, as well as the strong interaction between components of catalyst caused by electron transfer, accounts for the ultrahigh stability.