Nitrogen-Doped Bimetallic Carbide-Graphite Composite as Highly Active and Extremely Stable Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media

摘要

It is demonstrated that nitrogen-doped bimetallic carbide-graphite composite(N-Fe_2MoC-GC) has much superior oxygen reduction reaction (ORR) activityto commercial Pt/C with ultrahigh stability, and excellent anti-methanol andanti-CO performances. The N-Fe_2MoC-GC has a high initial half-wave potentialof 0.887 V (versus RHE); its mass activity (83 mA mgcat.?1 at 0.9 V versusRHE) is 2.2 times that of Pt/C (40 wt%, 39 mA mg_(cat.)~(?1)). In H_2/O_2 alkaline fuelcell, the N-Fe_2MoC-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 noblemetal-free catalysts reported to date. Moreover, the N-Fe_2MoC-GC keeps highpower density even under low relative humidity or at high operation temperature.The positive charge on Fe and Mo atoms caused by electron transferfrom Fe_2MoC to N is believed to lead to the excellent ORR activity. Theinherent electrochemical stability of the Fe_2MoC and graphite matrix, as wellas the strong interaction between components of catalyst caused by electrontransfer, accounts for the ultrahigh stability.