Synthesis of nitrogen-doped porous graphitic carbons using nano-CaCO3 as template, graphitization catalyst, and activating agent

Nitrogen-doped porous graphitic carbons (NPGCs) with controlled structures were synthesized using cheap nano-CaCO3 as template, melamine-formaldehyde resin as carbon precursor, and dilute HCl as template removing agent. In addition to its use as a template, the nano-CaCO3 acted as an internal activating agent to produce micro- and mesopores, as an adsorbent to remove the released hazardous gases (i.e. HCN, NH3), and as a mild graphitization catalyst. The obtained NPGCs with hierarchical nanopores contained as high as 20.9wt% of nitrogen, had surface areas of up to 834m2g–1, and also exhibited high thermal stability with respect to oxidation. Using carbohydrate or phenolic resin as the carbon precursor, this simple approach was also capable of producing hierarchical porous graphitic carbons with high surface area (up to 1683m2g–1) and extremely large pore volumes (>6cm3g–1). X-ray diffraction and infrared spectroscopy suggested that the intermediate CaCN2 or CaC2 generated during the carbonization plays a critical role in the formation of the graphitic structure.