Interface reinforced 2D/2D heterostructure of Cu-Co oxides/FeCo hydroxides as monolithic multifunctional catalysts for rechargeable/flexible zinc-air batteries and self-powered water splitting.

Elaborate engineering of heterostructure and composition to regulate the electroactivities remains a pronounced challenge. Herein, a self-supported 2D/2D heterostructure monolith is constructed by interlinked FeCo-hydroxides nanosheets tightly interlacing with aligned Cu 0.76 Co 2.24 O 4 nanoplates. Due to the well-defined hierarchical nanoarrays and desirable interfacial coupling, the monolithic catalyst can guarantee the rapid charge transfer and mass transport pathways for accelerated surface kinetics, leading to manifestly improved electroactivities and stability toward trifunctional catalysis. Both experimental and theoretical calculations unravel the enriched multimetal active sites for intermediates adsorption and the synergistic interplay of the heterostructure to achieve enhanced catalytic efficiency. Consequently, the heterostructure catalyst contributes to high-performance rechargeable/flexible all-solid-stated Zn-air batteries and water electrolyzer with an ultralow potential of 1.51 V. Moreover, self-powered water splitting system driven by flexible Zn-air batteries delivers a high H 2 generation rate. This cost-effective heterostructure monolith could open an intriguing avenue for advancing all-in-one films toward portable energy conversion/storage. [Display omitted] • A self-supported 2D/2D heterostructure monolith with rich multi-metal active sites is constructed from CuCo-oxides. • The monolithic catalyst exhibits superior multifunctional activities for HER/OER/ORR. • Rechargeable ZABs obtain high specific energy and excellent cycling stability for 400 h. • The overall water splitting cell delivers an ultralow potential of 1.51 V to achieve 10 mA cm−2. • Self-powered water splitting system driven by flexible ZABs is developed for H 2 production. [ABSTRACT FROM AUTHOR]