Self-template synthesized ZIF-derived polyhedron-connected porous Co–N–C as an oxygen reduction catalyst for Zn–air batteries

Abstract

The strategic development of high-efficiency electrocatalysts for the oxygen reduction reaction (ORR) remains a pivotal challenge in advancing high-performance zinc–air batteries (ZABs) towards commercial viability. In this work, we developed a template-directed synthesis strategy to prepare Co, N-co-doped polyhedral carbon 3D frameworks (Co–N–C-x) through controlled pyrolysis of Co-ZIF precursors grown on a Co–ZnO nanorod self-template. Owing to its unique carbon skeleton architecture and uniform dispersion of Co and N species, the optimized catalyst (Co–N–C-7%) exhibits enhanced ion/electron-transfer kinetics and improved mass transport capabilities. Consequently, the Co–N–C-7% catalyst exhibits superior ORR performance, showing a half-wave potential (E_1/2 = 0.878 V vs. RHE) that is 3 mV higher than that of commercial 20 wt% Pt/C (E_1/2 = 0.875 V vs. RHE), along with exceptional stability. When applied in ZABs, the Co–N–C-7% cathode delivers a higher peak power density (178 mW cm⁻²) compared to Pt/C-based counterparts (152 mW cm⁻²). This work provides a simple and reliable control scheme for designing cost-effective, high-performance, and durable ORR electrocatalysts.