Temperature-directed synthesis of N-doped carbon-based nanotubes and nanosheets decorated with Fe (Fe3O4, Fe3C) nanomaterials.

The coupling of N-doped carbon materials with transition-metal-based materials shows great promise for electrochemical energy conversion and storage. However, it is still a big challenge to achieve high-performance carbon-based composites with a simplified preparation process and a general synthesis strategy. Herein, a facile and efficient one-pot synthetic strategy was developed for the simultaneous preparation of N-doped one-dimensional carbon nanotube-based hybrids and two-dimensional carbon nanosheet-based hybrids through temperature-directed fabrication. A mixture containing dicyandiamide (DCDA), glucose, and FeCl3·6H2O as precursors was used. C3N4, derived from the pyrolysis of DCDA, acted not only as the self-sacrificing template to guide the formation of the distinct shape and structure of the hybrids, but also as the N and C sources for N-doped carbon materials. Meanwhile, FeCl3·6H2O served both as the catalyst to induce the transformation of the structure and as the reactive template affording an Fe reservoir to generate various Fe species. Effects of temperature on the structure and morphology as well as on the corresponding electrochemical performance of the hybrids were further studied in detail. Moreover, the as-prepared products demonstrated good capacitive performance. This work provides good guidance for the facile and efficient preparation of N-doped carbon-based materials with a distinct shape and structure.