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. Fe2O3 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 m2 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.