碳辅助金属配合物热解法制备高含量Fe-N4单原子催化剂用于氧还原反应

单原子催化剂凭借其超高的原子利用率及在某些反应中表现出的出色催化效果,被认为是最有前途的电催化剂之一,引起了研究人员的极大热情和兴趣.制备高金属含量的单原子催化剂是基础研究和实际应用的前提和关键.然而,由于原子表面自由能随着尺寸的减小而急剧增加,在制备和催化过程中,单原子催化剂的金属原子很容易聚集成团簇甚至颗粒,因此如...

Fabricating high-loading Fe-N4 single-atom catalysts for oxygen reduction reaction by carbon-assisted pyrolysis of metal complexes

Iron-based single-atom catalysts with nitrogen-doped carbon as support (Fe-SA/NPC) are consid-ered effective alternatives to replace Pt-group metals for scalable application in fuel cells. However, synthesizing high-loading Fe-SA catalysts by a simple procedure remains challenging. Herein, we report a high-loading (7.5 wt％) Fe-SA/NPC catalyst prepared by carbon-assisted pyrolysis of metal complexes. Both the nitrogen-doped porous carbon (NPC) support with high specific surface area and o-phenylenediamine (o-PD) play key roles role in the preparation of high-loading Fe-SA/NPC catalysts. The results of X-ray photoelectron spectroscopy, high-angle annular dark-field scanning transmission electron microscopy, and X-ray absorption fine structure spectroscopy experiments show that the Fe atoms are anchored on the carbon carriers in a single-atom site configuration and coordinated with four of the doped nitrogen atoms of the carbon substrates (Fe-N4). The activities of the Fe-SA/NPC catalysts in the oxygen reduction reaction increased with increasing iron loading. The optimized 250Fe-SA/NPC-800 catalyst exhibited an onset potential 0.97 V of and a half-wave potential of 0.85 V. Our study provides a simple approach for the large-scale synthesis of high-loading single-atom catalysts.