Ammoxidised carbons were produced from three different starting materials: an activated carbon obtained from wood by chemical activation using the phosphoric acid process, a steam activated peat-based carbon, and a char obtained from a low-cost biomass feedstock, olive stones. Nitrogen was successfully incorporated into the carbon matrix of the different materials, the amount of nitrogen uptake being proportional to the oxygen content of the precursor. At room temperature the CO2 capture capacity of the samples was found to be related to the narrow micropore volume, while at 100 degrees C other factors such as surface basicity took on more relevance. At 100 degrees C all the ammoxidised samples presented an enhancement in CO2 uptake compared to the parent carbons. (C) 2010 Elsevier B. V. All rights reserved.