Binary Fe, Co-N-doped carbon as a Highly Efficient Electrocatalyst for Oxygen Reduction Reaction

초록

Proton exchange membrane fuel cell (PEMFC) has been considered as one of the most promising power source candidates for future electric vehicles due to its high energy density, high conversion efficiency, and zero greenhouse gas emissions [1,2]. However, oxygen reduction reaction (ORR), which occurs at the cathode of PEMFC, is the kinetically sluggish process due to a complex 4 electron process. Owing to low cost, high stability, and high conductivity, carbon-based materials such as metal-nitrogen-doped carbon (M-N-C) catalysts have emerged as the efficient electrocatalysts to replace platinum group metals (PGM) [3]. Herein, we fabricated a bimetallic Fe, Co doped N-C (FeCo-N-C) using simple hydrothermal and pyrolysis method. First, defect-rich Ketjen black (D-KB) support was synthesized using hydrothermal method with H2O2, and followed by in situ thermal polymerization of Fe, Co-g-C3N4 on D-KB. Subsequently, the Fe, Co-g-C3N4 was decomposed by carbonization process at elevated temperature to achieve bimetallic FeCo-N-C. The FeCo-N-C exhibits superior electrochemical activity and long-term durability compared to commercial Pt/C, which may be attributed to the enhanced electric conductivity of D-KB support and introduction of abundant Fe-N and Co-N active sites on N doped carbon matrix. This work can be extensively applied to ORR catalysts for energy storage systems such as fuel cell and metal air batteries.