Hierarchical Porous Carbon with N/S Codoped Bimetal as a High-Efficiency Oxygen Reduction Catalyst for Rechargeable Zinc–Air Batteries

Transition metal-doped carbon catalysts are expected to replace noble metal catalysts for the oxygen reduction reaction (ORR). In this paper, a ZIF layer consisting of Co and Cu was formed on the surface of silica nanospheres, and then heteroatom S was added to obtain a porous carbon material catalyst (Co/Cu-NSC) after pyrolysis. Due to its porous structure, the Co/Cu-NSC catalyst has a large number of active sites with excellent ORR catalytic performance. The limiting current density of the Co/Cu-NSC catalyst is as high as 6.25 mA cm–2 (5.91 mA cm–2 of commercial Pt/C catalyst). The half-wave potential and onset potential of the Co/Cu-NSC catalyst are comparable to those of commercial Pt/C catalyst, and it has better stability and methanol resistance than commercial Pt/C catalyst. In addition, the Co/Cu-NSC catalyst affords excellent performance in a zinc–air battery, achieving high power density (145 mW cm–2) and continuous charge–discharge time (177 h) at 5 mA cm–2.