Formamide-soluble solid-state ZnO as Zn source for synthesizing FeCo–NC with ultrahigh oxygen reduction reaction activity

Abstract

The high-cost synthesis of highly dispersed non-noble metal–nitrogen–carbon (MNC) electrocatalysts hinders their practical applications. Here, we have developed a cost/time-efficient synthesis method for MNC electrocatalysts with highly dispersed metal sites, using the commercially available cheap ZnO as the Zn source, reducing the cost of Zn usage by over 80%. Our specially chosen solvent formamide can react with ZnO and allow the formation of nano-sized ZnFeCo–Nx complexes uniformly distributed in the formamide-derived high-N-doped carbon substrate. Further annealing the ZnFeCo–N–C precursor will produce a highly dispersed FeCo–NC target product. Electrochemical measurements show that the prepared FeCo–NC is an excellent electrocatalyst for alkaline oxygen reduction reaction (ORR), rendering superior onset and half-wave potentials of 1.05 and 0.92 V, respectively. The Al–air battery assembled using this also shows a high specific power (204.9 mW cm⁻²) and a large specific capacity (552 mA h g⁻¹ at 10 mA cm⁻²), exceeding those of the 20 wt% Pt/C catalyst. Our method may inspire the scalable and low-cost production of highly dispersed MNC electrocatalysts and their wide range of practical applications.