Bimetal-polyphenol coordination derived alloy nanoparticles on N-doped carbon for oxygen reduction reaction and Zn-air batteries

Developing efficient electrocatalysts and establishing their catalytic mechanisms carry considerable significance for oxygen reduction reaction (ORR) and Zn-air batteries (ZABs). Herein, a convenient and versatile bimetalpolyphenol coordination strategy was utilized to prepare controllable transitional metal alloy nanoparticles on N-doped carbon for ORR and ZABs. The coordination-directed assembly among Mn+, Co2+, ellagic acid (EA), and graphene oxide (GO) would drive the formation of MCo-EA/GO precursors, which were subsequently converted into alloy-carbon composites (MCo@NC: FeCo@NC, MnCo@NC and CrCo@NC). The pronounced metallic coupling effect within MCo@NCs induced the charge redistribution to raise the electron-transfer capability and decrease the reaction energy barrier, which endowed MCo@NCs a higher ORR catalytic activity than Co@NC. Encouragingly, FeCo@NC exhibited the highest onset potential, half-wave potential and stability in ORR, as well as the elevated open-circuit voltage and power density in ZABs.