Synthesis of trimetallic oxide/nitrogen-doped carbon composite using ZIF-guided combustion pyrolysis for efficient bifunctional oxygen catalysis in zinc-air batteries

초록

Multi-element catalysts coupled with heterogeneous atom-doped carbons have significant potential for bifunctional oxygen catalysis owing to multiple active sites and tunable electronic structures. However, their synthesis routes involve multi-step procedures, limiting efficient screening of optimal designs considering electrocatalytic performance. Herein, we present a single-step strategy for synthesizing Co/Ni/Fe trimetallic oxide (TO) catalysts within nitrogen-doped carbon (NC) networks via combustion pyrolysis of ZIF-67 metal-organic framework/NiO/Fe2O3 precursors. The ultrafast melting-recrystallization induced by a rapid heating-cooling duration (similar to 1.5 s) lead to uniformly mixing metal elements, enabling abundant oxygen vacancies/strong chemical bonds within the porous structure, and optimizing the energy barrier for bifunctional catalysis, while decreasing interfacial resistances. The optimized TO-NC catalyst exhibits excellent overpotential of 0.88 V, and provides outstanding power density (125 mW cm(-2)) and stability (>200h) to a liquid zinc-air battery, outperforming those with a Pt/C + Ir/C catalyst. This research establishes scalable yet tunable thermochemical fabrication of multi-element/carbon-based catalysts.

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