Phosphate‐Assisted Dispersion of Iron Phosphide in Carbon Nanosheets towards Efficient and Durable ORR Catalysts in Acidic and Alkaline Media

Abstract

AbstractHigh‐performance electrocatalysts, especially those consisting of earth abundant elements with low cost, are highly desirable for oxygen reduction reaction (ORR). However, design of well‐dispersed ORR catalysts that are efficient in both acidic and alkaline media remains challenging. Herein, we report a phosphate‐regulated synthesis with phytic acid, by dispersing the active sites in the carbon nanosheets to obtain Fe2P/FeP nanoparticles encapsulated in P, N‐doped carbon (PNC). The active sites of Fe2P/FeP particles and P, N‐doping sites have a synergistic effect on the ORR reaction. The Fe2P/FeP‐PNC catalyst exhibits good ORR performance and stability in alkaline media. The half‐wave potential (0.85 V), and 5 mV shift after 5000 cycles of stability test for Fe2P/FeP‐PNC catalyst exceed those of commercial Pt/C (E1/2=0.84 V, 20 mV shift) under alkaline condition. The catalyst presents a half‐wave potential of 0.70 V and limited current density of 5.31 mA cm−2 in acidic media. We demonstrate a Zn‐air battery and a PEMFC with the Fe2P/FeP‐PNC as the cathodes, showing a high power density of 156.68 mW cm−2 and 144 mW cm−2 respectively in either the alkaline or acidic electrolytes.