Mesoporous TiO2/ SiO2/ Ag ternary composite aerogels for high photocatalysis

TiO2/SiO2-Based nanocomposites with highly porous structures have received increasing attention due to their excellent photocatalytic activity. In this work, a TiO2/SiO2/Ag ternary composite aerogel with enhanced visible-light photocatalytic activity has been successfully synthesized through a facile sol-gel method combined with a supercritical drying technique. The specific surface area and pore structure of TiO2/SiO2/Ag aerogel could be controlled by adjusting the Si content. The TiO2/SiO2/Ag aerogel with pore size of 9.2 nm achieved the maximum adsorption capacity of oxytetracycline. The presence of SiO2 in TiO2/SiO2/Ag improved the compression strength of the aerogel and thus achieved long-term stability in photocatalysis. Furthermore, the addition of Ag particles in TiO2/SiO2/Ag effectively decreased the recombination of photo-electrons and holes. The photocatalytic degradation rates of oxytetracycline over the TiO2/SiO2/Ag aerogel with a mole ratio of Ag:Si:Ti = 0.1:10:4 were 3.1 and 2.3 times those over P25 and a TiO2/SiO2 aerogel. The enhanced photocatalytic performance of the TiO2/SiO2/Ag aerogel is attributed to the large specific surface area, 3-D porous structure, high electrical conductivity and compression strength of this novel composite aerogel.