One-pot sol–gel synthesis of amine hybrid titania/silsesquioxane composite aerogel for CO₂ capture

Abstract: Amine hybrid titania/silsesquioxane composite aerogel (AHTSA) was prepared by an one-pot sol–gel process without any catalyst. The sol-gel reaction mechanism of AHTSA was proposed. The use of 3-aminopropyltriethoxysilane (APTES) plays as an “internal catalyst” and promotes the formation of gel during sol–gel process. The morphology, microstructure, pore structure and CO₂ capture performances of AHTSA were investigated. AHTSA exhibits microstructure of the typical silica aerogels with colloidal structure. Moreover, AHTSA has a large number of macropores which favor the CO₂ adsorption. Thermogravimetric analysis reveals that AHTSA has a high CO₂/N₂ selectivity in CO₂/N₂ mixture gas. CO₂ adsorption capacity with dry and humid 1 vol% CO₂ is as high as 4.19 and 5.04 mmol/g, respectively. Correspondingly, amine efficiency under dry and humid conditions is 0.37 and 0.44, respectively. AHTSA has very short adsorption halftime below 4 min, and its CO₂ adsorption capacity do not show obvious attenuation after 30 adsorption-regeneration cycles, indicating AHTSA is a dynamic and regenerable sorbent. Graphical abstract: [InlineMediaObject not available: see fulltext.].