The development of efficient nonprecious metal catalysts for oxygen reduction reaction (ORR) is crucial but challenging. Herein, one simple and effective strategy is developed to synthesize bimetallic nitrogen-doped carbon catalysts by pyrolyzing Fe-doped Vitamin B12 (VB12) supported carbon black (Fe-VB12/C). A typical Fe₂₀-VB12/C catalyst with a nominal iron content of 20 wt% pyrolyzed at 700 °C exhibits remarkably ORR activity in alkaline medium (half-wave potential of 0.88 V, 10 mV positive than that of commercial Pt/C), high selectivity (electron transfer number > 3.93), excellent stability (only 6 mV negative shift of half-wave potential after 5000 potential cycles) and good methanol-tolerance. The superior ORR activity of the composite is mainly attributed to the improved mesoporous structure and co-existence of abundant Fe-N_x and Co-N_x active sites. Meanwhile, the metallic Fe are necessary for the improved ORR activity by means of the interaction of metallic Fe with neighboring active sites.

开发用于氧还原反应（ORR）的有效非贵金属催化剂至关重要，但具有挑战性。本文中，开发了一种简单有效的策略，通过热解铁掺杂的维生素B12（VB12）负载的炭黑（Fe-VB12 / C）来合成双金属氮掺杂的碳催化剂。典型的Fe ₂₀-在700°C时热解的标称铁含量为20 wt％的-VB12 / C催化剂在碱性介质中表现出显着的ORR活性（半波电势为0.88 V，比市售Pt / C正电10 mV），选择性高（电子转移数> 3.93），极佳的稳定性（5000个电势周期后半波电势仅发生6 mV负移）和良好的甲醇耐受性。复合材料优异的ORR活性主要归因于介孔结构的改善以及丰富的Fe-N _x和Co-N _x活性位点的共存。同时，金属Fe通过金属Fe与相邻的活性位点的相互作用对于提高ORR活性是必需的。