Incorporating inactive Nd2O3 into Co/N-doped carbon as bifunctional oxygen electrocatalyst for rechargeable Zn-air battery

Co-Nd2O3/N-doped carbon (NC) as bifunctional oxygen electrocatalyst was synthesized by annealing a bimetal precursor (Co, Nd). It exhibits a nanostructure of Co-Nd2O3 hybrid nanoparticles coated with NC shells. The introduced Nd2O3 is beneficial to obtain high ratios of O vacancy/total O and graphitic-N/total N and modify the Lewis acidic property of Co-Nd2O3/NC-700, thus benefiting the OER activity. Besides, not only high Co2+/total Co and pyridinic-N/total N ratios, but also the enhanced Lewis base property is achieved after the introduction of Nd2O3, which is favorable for the ORR activity. As a result, the optimal Co-Nd2O3/NC-700 exhibits the enhanced OER/ORR activity. Especially, the OER activity is remarkably improved, thus leading to the excellent bifunctional catalytic activity with low Delta E of similar to 0.86 V. Furthermore, the Zn-air battery with Co-Nd2O3/NC-700 shows a high specific capacity of similar to 613.6 mA h g(Zn)(-1) and superior charge-discharge cycling durability.