A “MOF-plus-MOF” strategy to synthesize Co-N3C1 single-atom catalyst for rechargeable Zn-air battery

Recently, single-atom catalysts (SACs) have exhibited highly efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalytic performance comparable to those of commercial noble metal catalysts. During the synthesis procedure, how to avoid the agglomeration of metal atoms is the key to the successful synthesis of single-atom catalysts. In this article, two metal organic frameworks (MOFs) were composited by a simple and efficient “MOF-plus-MOF” strategy. Then, Co single atoms stabilized by N-doped carbon (Co SAs @NC-920) were successfully prepared from ZnCo-ZIF@Zn-MOF-74 for the first time because of the novel pyrolysis behavior of the dual-MOF precursor. Thanks to the three-dimensional interconnected structures, large specific surface area, abundant N-active species and Co-N 3 C 1 single-atom configuration, Co SAs @NC-920 showed outstanding ORR/OER performance beyond that of commercial noble metal catalysts. Moreover, it displayed larger specific capacity, higher discharge power density and excellent cycling stability in the real rechargeable zinc-air battery (ZAB).