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
Wen‐Jun Niu, Qiao‐Qiao Sun, Jin‐Zhong He, Jiang‐Lei Chen, Bing‐Ni Gu, Mingjin Liu, Chia‐Chen Chung, Youzhi Wu, Yu‐Lun Chueh
Abstract
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.