Novel porous carbon materials with ultrahigh nitrogen contents for selective CO2 capture

Abstract

Nitrogen-doped carbon materials were prepared by a nanocasting route using tri-continuous mesoporous silica IBN-9 as a hard template. Rationally choosing carbon precursors and carefully controlling activation conditions result in an optimized material denoted as IBN9-NC1-A, which possesses a very high nitrogen doping concentration (∼13 wt%) and a large surface area of 890 m² g⁻¹ arising from micropores (<1 nm). It exhibits an excellent performance for CO₂ adsorption over a wide range of CO₂ pressures. Specifically, its equilibrium CO₂ adsorption capacity at 25 °C reaches up to 4.50 mmol g⁻¹ at 1 bar and 10.53 mmol g⁻¹ at 8 bar. In particular, it shows a much higher CO₂ uptake at low pressure (e.g. 1.75 mmol g⁻¹ at 25 °C and 0.2 bar) than any reported carbon-based materials, owing to its unprecedented nitrogen doping level. The high nitrogen contents also give rise to significantly enhanced CO₂/N₂ selectivities (up to 42), which combined with the high adsorption capacities, make these new carbon materials promising sorbents for selective CO₂ capture from power plant flue gas and other relevant applications.