MOFs-derived core-shell Co3Fe7@Fe2N nanopaticles supported on rGO as high-performance bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions
© 2020 Elsevier Ltd Exploring stable and highly efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for the novel energy conversion and storage devices including fuel cells and metal-air batteries. Herein, the core-shell structured Co3Fe7@Fe2N nanoparticles supported on reduced graphene oxide (rGO) nanosheets (Co3Fe7@Fe2N/rGO) is designed though the simple annealing of MOFs. The as-fabricated samples present an excellent electrocatalytic performance for ORR and OER due to the synergistic effect of electrode materials. The Co3Fe7@Fe2N/rGO exhibits an onset potential of 0.98 V (vs. Reversible hydrogen electrode), peak current intensity of 1.531 A g−1 and long-term stability for ORR, which is close to that of the benchmark Pt/C (20%) in 0.1 M KOH. It also shows good oxygen evolution reaction (OER) performance with an overpotential of 371 mV (at 10 mA cm−2). When used as a bifunctional air electrode in Zn-air batteries, the core-shell materials enabled an excellent mass power density of 60 W cm−2 g−1 at 0.57 V and stable cycling performance for over 100 cycles.