Zeolitic Imidazolate Framework-Derived Copper Single Atom Anchored on Nitrogen-Doped Porous Carbon as a Highly Efficient Electrocatalyst for the Oxygen Reduction Reaction toward Zn–Air Battery

Here, copper single atoms anchored on nitrogen-doped porous carbon (Cu-N/PC) derived from zeolitic imidazolate frameworks (ZIFs) as a highly efficient electrocatalyst for the oxygen reduction reaction (ORR) were demonstrated. Specifically, as a nitrogen-rich bridge molecule, tubular g-C3N4 (TCN) can trap free Cu ions through the electrostatic interaction in the initial stage. Then, Cu-ion-doped TCN can be used to regulate the content of copper and nitrogen doping, the electronic structure, as well as the specific surface area and pore diameter of Cu-N/PC. As a result, the high density of exposed Cu-N4 active sites and the high level of porosity in Cu-N/PC may significantly enhance the ORR activity with a more positive onset potential (E0 = 0.97 V versus reversible hydrogen electrode (RHE)) and half-wave potential (E1/2 = 0.88 V) than the commercially available Pt/C catalyst (E0 = 0.94 V, E1/2 = 0.85 V). Furthermore, the homemade Zn–air battery (ZAB) equipped with Cu-N/PC is able to deliver excellent performance, including a peak power density of 215.8 mW cm–2 and a specific capacity of 704.9 mAh g–1 based on Zn anode, outperforming the Pt/C catalyst. The finding highlights a new guideline for constructing Cu-N/PC catalyst with a well-designed structure and superior property for advanced fuel cell cathode materials.