Mesoporous carbon nitride (MCN) and carbon nitride-carbon (MCN/C) composites with a partly graphitized structure are synthesized by using mesoporous silica SBA-15 as a hard template and ethylenediamine and carbon tetrachloride as precursors, possessing uniform mesopore size of 6.3 nm, high surface area of 278-338 m(2)/g, and high nitrogen content of 20.5-24.9% with abundant basic sites. The synthesized MCN and MCN/C composites are used as adsorbents for CO2 capture, showing high adsorption capacity and good reusability. The presence of carbon coating layer in MCN/C composites introduced more micropores, which favored the capture of CO2, exhibiting high CO2 capture capacity of 3.05 mmol/g at 0 degrees C and 2.35 mmol/g at 25 degrees C and 760 mm Hg, with good CO2/N-2 selectivity and excellent regeneration stability. (C) 2012 Elsevier B.V. All rights reserved.