Preparation and Properties of Tremella-like Fe-N-C Composite Catalyst for Oxygen Reduction Reaction

Fe-N-C composite catalyst was prepared by thermal decomposition of chelate precursors based on Fe( III) central ions and o-phenylenediamine ligands. Scanning electron microscopy characterization showed that the crumpled carbon micro-and nano-sheets were intertwined and formed a free-standing tremella-like 3D structure. Notrogen adsorption/desorption experiments revealed that the composite contained ample micro-pores and meso-pores and had a specific surface area of 290 m(2) g(-1). Graphitic carbon and multi-crystal Fe3C as main components were confirmed by X-ray diffraction, and N-doping in the general form of graphite-N and pyridine-N was also verified by X-ray photoelectron spectroscopy. The electrochemical measurements showed that the tremella-like Fe-N-C composite catalyzed oxygen reduction through a four-electron path in an alkaline solution, and its activity was comparable to that of the commercial Pt/C catalyst. After 2000 cycles, the limiting current density of the Fe-N-C catalytic electrode only decreased less than 5%, and the half-wave potential negatively shifted 5 mV, suggesting that the Fe-N-C composite catalyst had better catalytic stability than the commercial Pt/C catalyst.