Highly ordered micro-meso-macroporous Co-N-doped carbon polyhedrons from bimetal-organic frameworks for rechargeable Zn-air batteries

Rational design of non-precious metal catalysts for efficient oxygen reduction and oxygen evolution reactions (ORR/OER) is important for rechargeable metal-air batteries. Building highly ordered porous structures while maintaining their overall crystalline orderliness is highly desirable, but remains an arduous challenge. Here, we have synthesized bimetallic metal-organic frameworks (MOFs) on highly ordered three-dimensional (3D) polystyrene templates by controlling the nucleation process. The ordered macropores with 190 nm diameters were uniformly distributed on the as-prepared ZnCo zeolitic imidazolate framework (ZnCo-ZIF). Afterwards, 3D ordered micro-meso-macroporous Co-N-doped carbon polyhedrons (3DOM Co-NCPs) was developed by calcination. With the synergy of the highly dispersed CoNC catalytic sites and the distinct porous structure, the synthesized 3DOM Co-NCPs exhibit impressive bifunctional activity. Additionally, the 3DOM Co-NCPs-900 for Zn-air battery exhibits extraordinary power density, high energy density, and acceptable stability. This approach offers a useful strategy for the fabrication of highly efficient electrocatalysts with 3D ordered porous.