In situ template reaction method to prepare three-dimensional interconnected Fe-N doped hierarchical porous carbon for efficient oxygen reduction reaction catalysts and high performance supercapacitors

A novel in situ templates etching method is used to prepare three-dimensional (3D) interconnected Fe-N doped hierarchical porous carbon materials. Citric acid serves as a carbon source and etchant. Fe 2 O 3 nanoparticles not only provide the iron source by in situ etching but also act as templates to construct the hierarchical porous structure. The prepared optimal sample displays a high specific surface area of 1643.6 m 2  g −1 with an interconnected abundant hierarchical porous structure and homogeneous distribution of Fe and N elements in the carbon. The optimized sample displays excellent catalytic oxygen reduction reaction (ORR) performance with a positive half-wave potential (0.85 V), efficient four-electron reaction and excellent durability, which are superior to those of Pt/C (20 wt%) catalyst. Meanwhile, due to the unique interconnected hierarchical porous structure, it also exhibits a high specific capacitance of 378.6 F g −1 at 0.5 A g −1 and an excellent rate capability of 276.6 F g −1 at 20 A g −1 as supercapacitors electrode materials in 6 M KOH. This work provides a simple design for the preparation of 3 D interconnected Fe-N doped hierarchical porous carbon electrode materials that display potential applications in ORR catalysts and supercapacitors.