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For the large-scale development of zinc-air batteries (ZABs), designing efficient, and cost-effective oxygen reduction reaction (ORR) electrocatalysts is crucial yet challenging. Herein, CuFe nanoparticles coupled with Cu–N x active sites co-anchored on 2D nitrogen–doped porous carbon nanosheets (CuFe@Cu–N–C) were obtained by the pyrolysis of Cu–MOF–74, nitrogen source, and ferric salt. The 2D porous carbon structure and the coupling effect between CuFe nanoparticles and Cu–Nx active sites endowed the CuFe@Cu–N–C electrocatalyst with excellent ORR electrocatalytic performance. Consequently, the CuFe@Cu–N–C electrocatalyst exhibited enhanced ORR activity with a higher half–wave potential than Cu–N–C, surpassing even that of the commercial 20 % Pt/C by 21 mV in alkaline media. Additionally, the CuFe@Cu–N–C electrocatalyst exhibited superior ORR stability to commercial 20 % Pt/C. Primary ZABs assembled with the CuFe@Cu–N–C as the cathode ORR electrocatalyst also showed excellent electrochemical properties. The work shows that the prepared CuFe@Cu–N–C electrocatalyst can serve as an ideal alternative to Pt-based catalysts for ZABs. [Display omitted] • A mixed pyrolysis method was proposed to prepare ORR catalyst (CuFe@Cu-N-C). • The CuFe nanoparticles coupled with Cu-N x effectively enhances ORR performance. • The CuFe@Cu-N-C with unique structure increases ORR activity. • The ZAB assembled with CuFe@Cu-N-C exhibits excellent performance. [ABSTRACT FROM AUTHOR]

Metal-free electrocatalysts for the oxygen reduction reaction (ORR) are the desired materials for metal–air batteries. Here, low-cost metal-free electrocatalysts of N-doped graphene supported on N-rGO nanosheets (N-graphene@N-rGO) using the composites of copper-based metal–organic frameworks (Cu-BTC) supported on GO (Cu-BTC@GO) for the efficient ORR are reported. The dispersant of GO was introduced into the structure to prevent the aggregation of Cu-BTC, and Cu-BTC could also provide steric hindrance to prevent the GO nanosheets from being stacked. The results indicate that N-graphene@N-rGO had more excellent ORR performance, better durability, and better methanol tolerance than 20 wt% Pt/C in alkaline solution. In addition, the peak power density of a two-electrode zinc–air (Zn–air) battery assembled with N-graphene@N-rGO as the cathode was 139 mW cm−2, which was higher than that of 20 wt% Pt/C (120 mW cm−2). Therefore, N-graphene@N-rGO using the synergy of N-graphene and N-rGO is a promising candidate compared to precious metal-based electrocatalysts for efficient Zn–air batteries. [ABSTRACT FROM AUTHOR]