Synthesis of SiO2–W x TiO2 composite aerogels via solvothermal crystallization under the guidance of bacterial cellulose followed by freeze drying method

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In order to obtain aerogel-based photocatalytic materials with higher adsorptivity and photocatalytic activity, SiO2–W x TiO2 composite aerogels were synthesized by the method of combining freeze drying with solvothermal crystallization under the guidance of bacterial cellulose using BC–SiO2 composite gel as skeleton. The influences of W/Ti mol ratio, solvothermal process parameters on the microstructure and properties of the SiO2–W x TiO2 composite aerogels were investigated. The results indicate that the obtained composite aerogels have higher specific surface area with 297–377 m2 g−1 and pore volume with 0.46–0.66 cm3 g−1. The adsorption/photocatalysis test indicates that the obtained aerogels showed prominent adsorption/photocatalytic activity, and the adsorption/photocatalytic degradation rate for Rhodamine B in aqueous solution could attain to 95 % within 120 min, which is obviously better than that of P25. With the increase of solvothermal crystallization time, the adsorption/photocatalysis tends to increase and the SiO2–W x TiO2 composite aerogel sample exhibited better removing efficiency for Rhodamine B. Doping of 2–3% W is favorable for improving the adsorption/photocatalytic properties of the SiO2–W x TiO2 composite aerogels. The SiO2–W x TiO2 composite aerogels were synthesized by the method of combining freeze drying with solvothermal crystallization under the guidance of bacterial cellulose (BC). The presence and hydrolysis of BC as a template and inducer during the solvothermal process played an important role in enhancing the porous network structure of the composite aerogels and inducing the deposition/crystallization of W x TiO2 nanoparticles. The SiO2–W x TiO2 composite aerogels exhibited higher adsorptivity and photocatalytic activity simultaneously.