Employing Co/Nd metal-organic framework derivatives on nitrogen-doped carbon as dual-function catalysts for high-efficiency rechargeable zinc-air batteries

Dual-function oxygen electrode electrocatalysts play a crucial role in the development of rechargeable Zn-air batteries (Z-ab), and the challenge of preparing low-cost, dual-function, and highly efficient catalysts remains. In this study, metal-organic frameworks (MOFs) serve as precursors, doped with rare earth elements Nd and Co, to synthesize N-doped carbon C substrates through high-temperature pyrolysis, resulting in catalysts with atomic distribution of rare earth Nd and Co. The rare earth Nd, with its unique electronic structure and excellent oxygen affinity, positively promotes catalytic performance. The catalyst prepared in this study exhibits outstanding dual- function electrocatalytic performance, with the overpotential of the Co/Nd@NC catalyst for Oxygen Evolution Reaction (OER) at 10 mA cm-2 being only 318 mV, significantly lower than that of the commercial IrO2 at 364 mV; the ORR half-wave potential of Co/Nd@NC reaches 0.814 V, surpassing that of commercial Pt/C at 0.806 V. Electrochemical in-situ infrared spectroscopy is employed to test the catalytic intermediates in the ORR catalytic reaction, combining theory with experiment. When applied to the oxygen electrode of rechargeable Zab, the catalyst demonstrates high power density, and the battery stably operates for 725 h in charge-discharge cycles, far exceeding the commercial Pt/C+IrO2. The catalyst shows excellent performance and long lifespan in rechargeable Z-ab, confirming its practicality.