Metal-Organic Framework Supported Dual Functional Air Cathode Carbon Nanofiber as an Efficient Electrocatalyst for the Rechargeable Zinc-Air Batteries.

Fabricating efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a major challenge in renewable energy technologies. To develop a high-performance bifunctional electrocatalyst, a strategy combining electrospinning, in-situ synthesis, and carbonization was employed to fabricate three-dimensional (3D) flexible porous carbon nanofiber electrocatalysts. A thermal treatment approach using in situ grown metal-organic frameworks (MOFs) is employed to synthesize highly porous, nitrogen-doped carbon nanotubes (N-CNTs) embedded with cobalt nanoparticles, along with hydroxy-functionalized boron nitride nanosheets (HO-BN) uniformly incorporated into electrospun carbon nanofibers (CNFs), forming a composite (N-CNT@MOF-Co/HO-BN/CNFs). Thus, the synthesized electrocatalyst reveals exceptional bifunctional catalytic performance for both the ORR and OER. This is indicated by a small potential gap of 0.70 V between the ORR half-wave potential and the OER potential at a current density of 10 mA cm, a value that is competitive with that of the mixed commercial noble catalyst made up of 30% Pt/C and IrO. The rechargeable zinc-air battery is designed to exhibit a noteworthy open-circuit voltage of 1.448 V, impressive power density (142.9 mW cm), and energy density (700 Wh kg). This research introduces a methodology for the synthesis and construction of high-performance bifunctional electrocatalysts.