FeOy@graphitic carbon core-shell nanoparticles loaded on two dimensional carbon nanosheets with exclusive Fe-Nx moieties for efficient oxygen reduction reaction

摘要

Fe-based nanoparticles encapsulated in carbon can effectively promote the ORR activity of the neighboring Fe-Nx and prevent the dissolution of metal nanoparticles to ensure the long-term durability of catalysts. Herein, we employed a facile two step pyrolysis strategy to construct "plane-active sites" structure, namely FeOy nanoparticles embedded in carbon were loaded on two dimensional (2D) porous carbon with exposed abundant Fe-Nx active sites (FeOy@C/Fe-Nx/C). The optimized FeOy@C/Fe-Nx/C catalyst with low Tafel slope (48 mV dec-1) and nearly-four-electron selectivity (3.91-3.97) showed excellent performance towards ORR with a more positive shift of 15 mV of half-wave potential (E1/2 = 0.856 V) than that of commercial Pt/C (E1/2 = 0.841 V) in alkaline solution, and also had a superior long-term stability and methanol resistance as compared with commercial Pt/C. The excellent electrochemical performance of FeOy@C/Fe-Nx/C can be attributed to FeOy@C structure, exposed abundant Fe-Nx active sites and two dimensional porous carbon with a large specific surface area.

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