A metal–organic framework derived cobalt oxide/nitrogen-doped carbon nanotube nanotentacles on electrospun carbon nanofiber for electrochemical energy storage

Carbon nanotubes (CNTs) and their nanocomposites have been a promising choice for next-generation technologies. However, synthesis of CNT-based controlled assembly, one of the worthy aspects of advanced nanomaterials, has rarely been reported. Synthesis of CNTs at low temperature and incorporation of active nanoparticles (NPs) are other current issues. Herein, synthesis of nitrogen-doped CNTs (N-CNTs) embedded with very small Co3O4 NPs is reported, for the first time, in the form of organized nanotentacles on electrospun carbon nanofiber (CNF) in a 3D array, at relatively low temperature with no need of external reducing gas and precursors, by self-templated metal–organic framework (MOF)-based approach. Self-templated MOF acts not only as a single source for CNTs, N-doping and small Co3O4 NPs ensuring a large specific surface area, high porosity, and even distribution of constituents but also owes an additional advantage of orienting the pre-designed controlled morphology. The as-constructed 3D Co3O4/N-CNTs@CNF, for supercapacitors, exhibits a promising performance. This idea of growing N-CNTs in pre-designed shape of self-templated MOF by just heating to relatively low temperature with no need of reducing gas, additives and expensive and complicated instruments, offers a new approach for creating metallic constituent incorporated CNT-based pre-designed a varieties of controlled nanoassemblies with the essence of MOF.