Nitrogen-doped porous carbon (N-carbon) with high nitrogen content was synthesized by carbonization of an ionic liquid. The hydrothermal and chemical stability of N-carbon was investigated by treatment in flowing steam, pure CO2, dry air, and dry SO2 at 130 degrees C. CO2 adsorption measurements before and after the treatments showed that, even under such severe conditions, in comparison to typical adsorption-desorption cycling, N-carbon was found to be a remarkably stable material for CO2 capture.