Well-dispersed carbon-coated or nitrogen-doped carbon-coated copper-iron alloy nanoparticles (FeCu@C or FeCu@C-N) in carbon-based supports are obtained using a bimetallic metal-organic framework (Cu/Fe-MOF-74) or a mixture of Cu/Fe-MOF-74 and melamine as sacrificial templates and an active-component precursor by using a pyrolysis method. The investigation results attest formation of Cu-Fe alloy nanoparticles. The obtained FeCu@C catalyst exhibits a catalytic activity with a half-wave potential of 0.83 V for oxygen reduction reaction (ORR) in alkaline medium, comparable to that on commercial Pt/C catalyst (0.84 V). The catalytic activity of FeCu@C-N for ORR (Ehalf-wave =0.87 V) outshines all reported analogues. The excellent performance of FeCu@C-N should be attributed to a change in the energy of the d-band center of Cu resulting from the formation of the copper-iron alloy, the interaction between alloy nanoparticles and supports and N-doping in the carbon matrix. Moreover, FeCu@C and FeCu@C-N show better electrochemical stability and methanol tolerance than commercial Pt/C and are expected to be widely used in practical applications.
Keywords: Cu-Fe alloys; metal-organic frameworks; nanoparticles; oxygen reduction reaction.
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