Metal–organic framework-induced construction of actiniae-like carbon nanotube assembly as advanced multifunctional electrocatalysts for overall water splitting and Zn-air batteries

Nowadays, rational design and simple synthesis of multifunctional non-noble electrocatalysts with high activity and low cost remain a great challenge. In present work, a novel and simple MOF-induced strategy is developed to construct three-dimensional actiniae-like carbon nanotube assembly (3D-CNTA) as effective and low-cost multifunctional electrocatalysts for overall water splitting and Zn-air batteries. In this strategy, ZIF-67 is used as the precursor, which also serves as the structure inducer, and melamine is chosen as an initiator for orientated growth of carbon nanotubes (CNTs). The resultant 3D-CNTA is assembled from a large number of one-dimensional (1D) CNTs, and it possesses superior conductivity, high specific surface area (108.12 m² g⁻¹) and abundant hierarchically porous structure. Meanwhile, each CNT is capped with zero-dimensional (0D) synapse-like Co@N-doped carbon core-shell particles (Co@NC), and the core-shell structure could expose the catalytic active sites to the electrolyte to the most extent and meanwhile protect the Co species from corrosion in the electrolyte. The integrated effects of the above factors endow 3D-CNTA excellent multifunctional electrocatalytic performances in terms of overall water splitting and zinc-air batteries. Our work provides a guide to rational design of micro-structures of the materials to achieve their multifunctional properties.