One Pot Synthesis of FeCo/N-Doped 3D Porous Carbon Nanosheets as Bifunctional Electrocatalyst for the Oxygen Reduction and Evolution Reactions

In this work, FeCo/N-doped porous carbon nanosheets (FeCo/NPC) were in-situ synthesised as bifunctional oxygen catalyst following a sodium chloride (NaCl) template-assisted strategy. The results show that this strategy assists in generating a 3D interconnected carbon nanosheets network with hierarchical pores and a larger specific surface area through a stencil effect. X-ray photoelectron spectroscopy (XPS) results show that the Fe 2p(3/2) and Co 2p(3/2) core-level binding energy (BE) of the FeCo/NPC catalyst exhibits a positive shift compared to monometallic catalysts, which is associated with downshifts of the d-band position of the metal by alloying and weakening of the interaction between oxygenic species and metal surfaces, thereby improving the catalytic activity. The FeCo/NPC catalyst shows excellent electrocatalytic activity for bothoxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solution: a high onset potential of 0.92V (vs. RHE), only 10mV difference of half-wave potential comparable with commercial Pt/C (20wt%), a high current retention of 95.7% after stability test of 20000s for ORR and a potential of 1.68V (vs. RHE) for OER at 10mAcm(-2). The high catalytic performance of the FeCo/NPC catalyst and the simplicity of the synthesis method provide a possibility for its practical application in metal-air batteries.