Metal-organic gel-derived Fe-Fe2O3@nitrogen-doped-carbon nanoparticles anchored on nitrogen-doped carbon nanotubes as a highly effective catalyst for oxygen reduction reaction

•A urea/CNTs-decorated MOG(Fe) was pyrolyzed as a new route to obtain an ORR catalyst.•The catalyst has nano-sized Fe-Fe2O3@N-doped-C structures anchored on N-doped CNTs.•The catalyst shows a E1/2 of 0.72 V and high catalytic stability in 0.1 M KOH.•It is one of the best Fe-FexOy catalysts in alkaline electrolytes reported so far.

A urea/carbon nanotubes (CNTs)-decorated metal-organic gel(Fe) was used as self-sacrifice precursors to prepare nano-sized Fe-Fe2O3@N-doped-C(NC) particles scattered on N-doped CNTs (NCNTs) through pyrolysis at 700 °C in N2. The particles with average size of ∼10 nm have core@shell structures with Fe-Fe2O3 cores and NC shells, and the Fe-Fe2O3 cores effectively connect with the NCNT scaffolds via the NC shells. Such a unique structure makes the material a superior oxygen reduction catalyst with an early onset potential (0.92 V), an early half-wave potential (0.72 V), a high current retention (91.7%, after 20,000 s), and good methanol tolerance in an alkaline electrolyte, enabling the catalyst the best among the developed Fe-FeOx oxygen reduction catalysts.

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