Is heteroatom doping of activated carbons always a good strategy for enhancing CO2 adsorption?
Résumé
This study shows the substantial impact of textural properties, with greater weight than N-doping, on CO 2 adsorption by carbon materials over a pressure range from 1 to 25 bar and a temperature range from 273 to 323 K. It also highlights the importance of providing volumetric CO 2 adsorption capacities when presenting newly developed materials. These results were obtained by exploring the influence of O-and N-doping on CO 2 uptake on 14 activated carbons (ACs) with distinct specific surface areas, from 1736 to 3200 m 2 /g, and micropore fractions from 37 to 96 %. Based on 3 commercial ACs, N content was maximized by hydrogen peroxide oxidation and urea treatment, reaching around 11 at.%. ON doping mainly impacted the largest pores, reducing material textural properties and thus CO 2 adsorption, although it improved CO 2 /N 2 selectivity, especially up to 5 bar and between 273 and 323 K. The contribution of heteroatoms to CO 2 uptake was particularly significant at low pressures and high temperatures, with threshold pressures increasing at higher temperatures. Breakthrough simulations were also carried out and the results demonstrate that, despite a lower specific surface area, the Odoped material exhibited longer breakthrough times than its commercial counterpart. This can be attributed to a balance between CO 2 adsorption capacity, governed by the textural properties, and tap density, i.e., adsorption capacity per unit volume.
Domaines
Matériaux
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co2_capture_vfierro_tohal (2).pdf (1.82 Mo)
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SI_CO2 capture_hal.docx (867.69 Ko)
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