Li, Hong; Shu, Xinxin; Xi, Haolong; Lv, Zhengxing; Tian, He; Zhang, Jintao; Xia, Haibing

JOURNAL OF MATERIALS CHEMISTRY A

2022, 10, 2050-7488

Li, Hong; Shu, Xinxin; Xi, Haolong; Lv, Zhengxing; Tian, He; Zhang, Jintao; Xia, Haibing

In this work, Fe-Cu diatomic nanoclusters (Fe-Cu DA-NCs) with sizes of 0.5-2.5 nm loaded in porous carbons (denoted as Fe-Cu DA-NC/C) were successfully prepared by virtue of the strong chelation interaction between tannic acid (TA) and metal ions (Cu2+ and Fe3+) as well as the doping interaction between metal ions and imino groups from polyaniline (PANI) chains. A detailed analysis revealed that Fe-Cu DA-NCs are composed of longitudinal N-2-Fe-O-Fe-N-2 units and latitudinal N-3-Cu-S-Fe-S-Cu-N-3 units, and are proposed as a new type of active site for the oxygen reduction reaction (ORR) for the first time, to the best of our knowledge. Thanks to the appropriate cluster sizes of 0.5-2.5 nm and the bimetallic active sites, the as-prepared Fe-Cu DA-NC/C catalysts have a favourable interface micro-environment for the adsorption and desorption of intermediates, thus leading to an enhanced electrocatalytic performance. Accordingly, the as-prepared Fe-Cu DA-NC/C catalysts exhibited a higher half-wave potential (E-1/2 = 0.951 V), a larger kinetic-limiting current density (38.5 mA cm(-2) at 0.9 V) and better long-term stability in alkaline media, compared with commercial Pt/C catalysts (E-1/2 = 0.89 V). Moreover, the fabricated Zn-air batteries also exhibited a remarkable performance and exceptionally high stability.