Design And Synthesis of Low Pt Loaded Mn-ZIF-67 Derived Bifunctional Electrocatalyst for Oxygen Electrode in Metal Air Batteries /

Abstract

Zinc-air batteries with rechargeable technology also make them good green energy storage options because of the high-test energy density (1085 kW h/kg), low cost, and eco friendliness. However, the sluggish oxygen reduction and evolution reaction (ORR and OER) kinetics limit the performance and efficiency of RZABs. Noble metal-based electrocatalysts have the potential to improve oxygen redox reactions, but they are scarce and unstable. To mitigate this issue, this study introduces a noble-metal-loaded, transition metal-based electrocatalyst derived from ZIF67. After pyrolysis, a nanoporous carbon structure with well-dispersed PtMnCo nanoparticles was obtained. The resulting Pt@ Mn Co/N-C catalyst exhibits a half-wave potential of 0.86 V with a limiting current density of 5 mA/cm², surpassing the commercially available Pt/C electrocatalyst (0.84 V and 3.24 mA/cm²) for ORR. It also demonstrates high performance in OER, with an overpotential of 0.34 V, significantly lower than commercial RuO₂ (0.57 V). The catalyst maintains stability even after 1000 CV cycles. The observed potential gap (ΔE) for Pt@MnCo/N-C is 0.71 V, establishing it as an efficient bifunctional electrocatalyst. This improved performance is attributed to the synergistic effect of metal alloys and the nanoporous carbon network, which together increase the surface area of electrocatalyst and provide electrochemically active sites for oxygen reactions. The robust and high performance of Pt@ Mn Co/N-C make it a very effective contender for rechargeable zinc air batteries.