Nanocast nitrogen-containing ordered mesoporous carbons from glucosamine for selective CO2 capture

Abstract D-glucosamine is investigated as non-toxic and sustainable carbon/nitrogen source for the templated synthesis of nitrogen-containing CMK-8 ordered mesoporous carbons (NOMCs) conceived for selective CO2 uptake. Pyrolysis temperature is varied during nanocasting using KIT-6 silica hard template to tailor microporosity and nitrogen inclusions. NOMCs exhibit large surface area (600–1000 m2g-1) and excellent pore ordering. The CO2/adsorbents interaction energy is estimated by the isosteric enthalpy of adsorption (∼33–40 kJmol-1) and the Henry’s constants. The role of nitrogen content (∼7–12 at.%) and of each type of N-species on CO2 adsorption is studied by X-ray photoelectron spectroscopy and CO2/N2 selectivity is attributed, being pyridinic functionalities the most effective ones. NOMCs are tested at different temperature, gas flow composition, reversibility, etc.; in all tested conditions, they outperform homologous bare sucrose-derived carbon. Enhancing micropore volume allows achieving maximum adsorption capacity in pure CO2 (1.47 mmolg–1 at 30°C/0.9 bar), while increasing surface N-content accounts for highest selectivity in CO2/N2 mixtures (20/80 v/v) at 35°C/1bar (maximum CO2 uptake 0.82 mmolg-1). The combination of suitable C/N precursor and hard templating synthetic route is effective for obtaining high performing, sustainable and reusable selective CO2 sorbents, without any activation steps or N-doping post-treatments.