CO ₂ Adsorption over Carbon Aerogels: the Effect of Pore and Surface Properties

Abstract: In order to investigate the effect of the pore and surface properties of carbon aerogels on carbon dioxide adsorption, carbon aerogels were synthesized at different calcination temperatures. The adsorbents were characterized by various technologies, such as X-ray diffraction, Raman, N ₂ sorption, and Fourier transform infrared technologies. It was found that the adsorption sites for CO ₂ caused by pore and surface of the adsorbent determined the CO ₂ adsorption abilities. The CA-800 sample carbonized at 800 °C showed the excellent CO ₂ adsorption capacity (93.98 cm ³ ⋅g ⁻¹ at 0 °C) because of the largest pore volume (1.55 cm ³ ⋅g ⁻¹ ) and the highest relative microporous volume determined by the ratio of microporous volume and total volume (0.31/1.55). The richness of the surface functional groups of the carbon aerogels declined and the surface defects determined by the intensity ratio of D and G bands (I _D /I _G ) increased from 0.7584 (CA-600) to 1.1029 (CA-900) gradually as the carbonization temperature increasing. It was used to predict the relationship between the CO ₂ adsorption capacity and the structure properties by the means of equation fitting. The result showed that the highest ratio of V _micro /V _tol and the lowest surface defects were crucial to the CO ₂ adsorption performance.