Ultrafine Co nanoislands grafted on tailored interpenetrating N-doped carbon nanoleaves: An efficient bifunctional electrocatalyst for rechargeable Zn-air batteries

Abstract

• Decussation-shaped D-Co@NC nanoleaves are fabricated by enzyme modulator. • The formation mechanism for decussation-shaped D-Co@NC is investigated. • D-Co@NC affords 5.2 times higher active area than the conventional dodecahedral one. • D-Co@NC shows a superior bifunctional catalytic activity for ORR and OER. • D-Co@NC-based Zn-air battery exhibits a high energy density of 879.6 Wh kg −1 . Zeolitic imidazole frameworks (ZIFs) provide an exciting platform to design and fabricate non-precious-metal carbon-based catalysts for oxygen reduction/evolution reaction (ORR/OER). Herein, we elaborately design a facile enzyme-assisted synthetic strategy that enables to tailor the ZIFs precursors into structural stable decussation shape, which derived Co nanoislands grafted on decussate N-doped carbon nanoleaves (D-Co@NC) can well retain the interpenetrating nanostructure. Benefiting from the combined advantages of compositions and interpenetrating nanostructures, D-Co@NC possesses 5.2 times higher exposed electrochemical active area than the conventional dodecahedral one, thus endowing the superior bifunctional activity toward ORR and OER with a low potential gap (ΔE) of 0.866 V. When applicated in Zn-air battery, the D-Co@NC electrode displays a high peak power density of 115.4 mW cm −2 and energy density of 879.6 Wh kg −1 as well as excellent long-cycling stability more than 200 h, outperforming benchmark catalysts of Pt/C||RuO 2 . The work provides a promising way to construct ZIFs-derived non-precious-metal electrocatalyst for advanced metal-air batteries.