Low-Temperature Synthesis of Mesoporous Cobalt(II) Carbide Using Graphene Oxide as a Carbon Source

A simple and efficient synthesis of Co₂C using graphene oxide (GO) as a carbon source has been established. The procedure consists of two steps: (1) formation of a GO/Co₃O₄ nanocomposite via the ammonia-evaporation-induced method and (2) conversion of Co₃O₄ to Co₂C under a H₂/N₂ mixture at a low temperature (200 °C). Transmission electron microscopy (TEM) analysis showed that Co₂C has a crystallite size of around 5 nm and a mesoporous structure with a pore size of ca. 3–5 nm. The amphiphilic behavior of GO contributes to the high porosity, large specific surface area, and narrow pore size distribution of the Co₂C. Tungsten carbide has also been successfully obtained using GO as a carbon source at a much lower temperature than that of the traditional carbothermal synthesis. Therefore, this method could be extended to the production of other important carbides with desired mesoporous features at low temperatures