Multi-metal (Fe, Cu, and Zn) coordinated hollow porous dodecahedron nanocage catalyst for oxygen reduction in Zn–air batteries†

Abstract

The coupling of multiple low-cost metals and porous nanocarbon materials aimed at replacing precious metals to enhance electrocatalytic oxygen reduction is a critical challenge in some crucial research areas. In the present study, a hollow dodecahedron nanocage catalyst (Fe₃O₄/CuNCs/ZnN_x-PHNC) was constructed by supporting copper nanoclusters, Fe₃O₄ nanoparticles, and Zn–N_x after sintering and annealing through the coordination of ZIF-8 and by doping copper and iron ions. We observed that the synergy of the multi-metals in the magnetically separable heterojunction catalyst induced electron transfer and inhibited hydrogen peroxide formation, thus improving its catalytic performance for the oxygen-reduction reaction. The catalyst demonstrated a half-wave potential as high as 0.832 V and a Tafel slope of 54 mV decade⁻¹, superior to many non-precious metal catalysts reported in the literature. The assembled Zn–air battery (ZAB) exhibited a maximum power density of 162 mW cm⁻² and ultrahigh stability of >500 h at 5 mA cm⁻² current density. The ZAB's excellent performance indicates its high development and practical application prospects.