Construction of amine-modified silica‑titanium composite aerogel and its CO2 adsorption and photoreduction performance

Green sol-gel/supercritical drying yields amine-modified silica-titania aerogel. • Uniform TiO 2 & amine grafting via terephthalic acid and ammonia/fluoride. • High CO 2 uptake (3.88 mmol g −1 ) and excellent stability (>88% after 10 cycles). • Solar-driven photocatalytic CO production (34.6 μmol g −1  h −1 ) via Ti-O-Si junction. To address the global climate crisis caused by carbon dioxide (CO 2 ) emissions, achieving “carbon neutrality” requires the construction of an efficient artificial carbon cycle. However, traditional carbon capture and utilization technologies have bottlenecks. Using tetrabutyl titanate, terephthalic acid and tetraethyl orthosilicate as precursors, amine modified silicon titanium composite aerogel was successfully prepared by using sol gel method combined with supercritical drying technology and the introduction of ammonia and ammonium fluoride. Systematic characterization reveals that the specific surface area of this sample is as high as 548.12 m 2  g −1 , and it simultaneously achieves an adsorption capacity of 3.88 mmol g −1 , exhibiting excellent adsorption properties and outstanding cyclic stability. In the CO 2 photoreduction performance test, STA-300 exhibited excellent synergistic effects of adsorption and photocatalysis. The principle is that the surface amino group enriches CO 2 molecules through chemical adsorption, improving the local concentration of active sites, TiO 2 components are stimulated by light to produce photogenerated electrons, and the enriched CO 2 is activated by photogenerated electrons and reduced to CO. This study provides an effective strategy for designing composite aerogel materials with both adsorption enrichment and photocatalytic conversion functions.