Engineering Strategy for Enhancing the Co Loading of Co–N4–C Single-Atomic Catalysts Based on the ZIF-67@Yeast Construction

The Co–N4–C single-atom catalysts (SACs) have attracted great research interest in the energy storage and conversion fields owing to 100% atom utilization. However, enhancing the Co loading for higher electrocatalytic performance is still challenging. In this context, we propose an engineering strategy to fabricate the high Co atomic loading Co–N4–C SACs based on the zeolitic imidazolate framework-67 (ZIF-67)@yeast construction. The rich amino groups provide the possibility for Co2+ion anchorage and ZIF-67@yeast construction via the biomineralization of yeast cells. The functional design induces the formation of Co–N4–C sites and regulates the porosity for exposure of such Co–N4–C sites. As a result, the Co–N4–C sites were anchored on spherical micrometer flower carbonaceous materials through our novel strategy. The as-obtained optimal sample exhibited a Co atomic loading of 12.18 wt % and a specific surface area of 403.26 m2g–1. High Co atomic loading and large specific surface area delivered excellent electrocatalytic kinetics as well as a high discharge voltage of 1.08 V at 10 mA cm–2for more than 100 h in Zn–air batteries. This work represents a promising strategy for fabricating high-loading SACs with high activity and good durability.