Iron and nitrogen co-doped carbons show great potential for high-performance electrochemical oxygen reduction reaction. However, the rational design of atomically dispersed iron over nitrogen-doped carbons with activity comparable to that of Pt-C is still challenging. Herein, we develop a new approach that enables the direct formation of intrinsically nitrogen-functionalized two-dimensional sheet-like carbons containing a high concentration of single Fe atoms. This strategy only involves one-step pyrolysis of both, guanine and iron nitrate, without using any guiding agent and sacrificial template. The electrochemistry tests demonstrate an excellent ORR performance of the prepared Fe-N_x-C catalyst with a half-wave potential of 0.85 V and a limited current density of −6.5 mA/cm² in alkaline medium, outperforming the commercial Pt-C and most of previously reported Fe-N_x-C catalysts. We believe that the emergence of superior ORR performance is mostly attributed to the uniform dispersion of single Fe atoms at the molecular level and the formation of abundant coordinated Fe-N_x sites. In addition, the high surface area, optimal porosity and defective structure (particularly the defects at the edge) of the two-dimensional carbons are also beneficial for the improved ORR activity.

铁和氮共掺杂碳显示出用于高性能电化学氧还原反应的巨大潜力。但是，合理设计具有与Pt-C相当活性的氮掺杂碳原子分散铁的方法仍具有挑战性。本文中，我们开发了一种新方法，可以直接形成包含高浓度单个Fe原子的内在氮官能化的二维片状碳。该策略仅涉及鸟嘌呤和硝酸铁的一步热解，而无需使用任何引导剂和牺牲模板。电化学测试表明，制得的Fe-N _x -C催化剂具有出色的ORR性能，半波电势为0.85 V，极限电流密度为-6.5 mA / cm ²在碱性介质中，性能优于市售的Pt-C和大多数以前报道的Fe-N _x -C催化剂。我们相信，ORR性能优异的出现主要归因于单个Fe原子在分子水平上的均匀分散以及大量配位的Fe-N _x位点的形成。此外，二维碳的高表面积，最佳孔隙率和缺陷结构（尤其是边缘缺陷）也有利于提高ORR活性。