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

Abstract

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.