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In situ growth of intertwined trinuclear copper complexes (nCu3) on a cellulose-derived carbon support (CMC) produced a high-performance electrocatalyst (CMC–nCu3) for the oxygen reduction reaction (ORR), which demonstrated superior performance in zinc–air batteries compared to a commercial Pt/C catalyst. This work highlights the importance of copper-based molecular catalysts with rich and intertwined tricopper structures for boosting both ORR activity and stability. [ABSTRACT FROM AUTHOR]

Bioinspired by the active sites of multicopper oxidases (MCOs), bi/multinuclear copper complexes have attracted great attention in promoting catalytic activity for the oxygen reduction reaction (ORR). Herein, we report the preparation of a Cu–N–C electrocatalyst Cu-BPOZ@CNB-400 for efficient ORR, which was obtained by low temperature pyrolysis of a dinuclear 2,5-bis(2-pyridyl)-1,3,4-oxadiazole (BPOZ) copper complex loaded on a N-doped carbon support at 400 °C. Cu-BPOZ@CNB-400 exhibited a half-wave potential (E1/2) of 0.86 V vs. RHE for the ORR in 0.1 M KOH solution, which was significantly higher than that of the Cu-BPOZ@CNB-800 (E1/2 = 0.83 V) catalyst treated under high temperature (at 800 °C) and the control catalyst Cu-Phen@CNB-400 (E1/2 = 0.82 V) derived from low-temperature-treatment (at 400 °C) of a mononuclear phenanthroline-coordinated-Cu complex loaded on a N-doped carbon support. When Cu-BPOZ@CNB-400 was applied as the cathode catalyst in zinc–air batteries a maximum power density (Pmax) of 127 mW cm−2 could be achieved, demonstrating comparable catalyst performance to the commercial 20 wt% Pt/C (Pmax = 122 mW cm−2) and the control Cu-Phen@CNB-400 catalyst (Pmax = 105 mW cm−2) under similar experimental conditions. Low-temperature pyrolysis of dinuclear copper complexes on a carbon support improved the charge transfer efficiency, inhibited metal aggregation, and could produce highly dispersed Cu–N–C catalysts with dinuclear copper sites for promoting the 4e−-reduction selectivity of the ORR. It thus provides a cost-effective approach for the controllable fabrication of efficient ORR catalysts to be applied for energy conversion devices. [ABSTRACT FROM AUTHOR]