Precisely tailoring ZIF-67 nanostructures from cobalt carbonate hydroxide nanowire arrays: toward high-performance battery-type electrodes

The controllable synthesis of metal-organic frameworks with diverse morphologies is highly desirable for many potential applications, but it still remains a big challenge. In this study, we for the first time report a facile and green route to the synthesis of ZIF-67 at room temperature by transformation of water-insoluble cobalt carbonate hydroxide nanowires in the presence of 2-methylimidazole. When cobalt carbonate hydroxide nanowires were grown onto a Ni foam substrate, four different kinds of ZIF-67 nanocrystal morphologies were synthesized. In particular, a ZIF-67-based nanotube array was used as an example for synthesis of a mesoporous Co3O4 nanotube array, which showed greatly enhanced performance as a battery-type electrode in comparison to the directly converted Co3O4 nanowire array from cobalt carbonate hydroxide. Our study provides a new insight into the preparation of metal-organic frameworks with tunable morphologies; in addition, the as-synthesized ZIF-67-based nanostructures are promising materials for other applications.