Bimetallic Co3.2Fe0.8N–Nitrogen–Carbon Nanocomposites for Simultaneous Electrocatalytic Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution

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To develop an efficient and inexpensive electrocatalyst with the ability to catalyze ORR/OER/HER synchronously, a Co–Fe bimetallic nitride combined with a transitional metal-N-doped carbon nanocomposite has been crafted via the sodium borohydride reduction and following nitride treatment. Electrochemical characterization has signified that the resulting Co–Fe bimetallic nitride with a Co/Fe molar ratio of 4:1 is highly active for electrocatalysis of OER with the lowest overpotential at 10 mA cm –2 (419 mV) among all the tested Co–Fe nitrides, even lower than that of the IrO 2 benchmark, and also active on HER. Further, a ZIF-derived carbon has been added to form a Co 3.2 Fe 0.8 N/MNC nanocomposite with better trifunctional activity for OER/ORR/HER than that of the single Co 3.2 Fe 0.8 N nanoparticle. The unique nanocomposite structure, which is flower-like nanosheets attached on the surface of depressed walnut-like spheres, electronic interaction between the Fe and Co atoms, and rich M–N or N–C active sites created by MNC joining into Co 3.2 Fe 0.8 N would explain the outstanding trifunctional catalytic activity. Moreover, the obtained Co 3.2 Fe 0.8 N/MNC nanomaterial has superior long-term stability for ORR, HER, and OER. Therefore, as a strong competitor to Ir- or Pt-based electrocatalysts, this bimetallic Co–Fe nitride/MNC nanocomposite has been expected to be incorporated into clean and efficient energy devices.