Strong coupling Fe2VO4 nanoparticles/3D N-doped interconnected porous carbon derived from MOFs by confined adsorption-assembly-pyrolysis for greatly boosting oxygen reduction.

Low-cost and effective electrocatalysts are critical for energy storage and conversion. Herein, iron(III) and vanadium(III) acetylacetonates were first adsorbed and confined in porous zeolitic imidazolate framework-8 (ZIF-8), which further cross-linked together by the methanol-induced-assembly. Following the pyrolysis, the Fe2VO4 nanoparticles were efficiently encapsulated within three-dimensional (3D) N-doped interconnected porous carbon, termed Fe2VO4/NIPC. The obtained Fe2VO4/NIPC displayed outstanding catalytic properties in the alkaline media for oxygen reduction reaction with a half-wave potential of 0.86 V. In the parallel, density functional theory (DFT) calculations were performed to illustrate the catalytic mechanism. Moreover, the Fe2VO4/NIPC assembled Zn-air battery showed a high peak power density of 107.7 mW cm-2 and excellent long-cycle stability over a duration of 250 h, which outperformed commercial Pt/C catalyst in the control group. The strong coupling and synergistic effects between the Fe2VO4 nanoparticles and N-doped carbon improved the catalytic performance, coupled by promoting the stability. This study opens a prospect way to develop high-efficiency carbon-based electrocatalysts in energy storage and conversion devices.