A comparative study of TiO₂-C hybrid aerogels from TiCl₄ or Ti(OBu)₄ for photocatalytic methylene blue degradation

TiO₂-C hybrid aerogels were obtained by a one-pot sol-gel method, followed by supercritical drying and pyrolysis, using resorcinol (R) and furfural(F) as carbon sources, and TiCl₄or Ti(OBu)₄ as the TiO₂ precursor. The hybrid aerogels were characterized by XRD, HR-TEM and N₂ adsorption. The photocatalytic activity of the samples was evaluated based on the conversion of methylene blue (MB) under UV light. Results showed that the type of precursor and the mass ratio of TiO₂ to carbon influenced the surface area and MB conversion. The TiO₂-C hybrid aerogels using TiCl₄ as TiO₂ precursor had a higher surface area and a better photocatalytic activity than those using Ti(OBu)₄ as precursor under otherwise identical conditions. The best sample was obtained when TiCl₄ was used and the TiO₂ content was 40%. This had the largest average pore size of 7.8 nm, the highest mesopore volume of 0.40 cm³/g and the highest MB conversion of 99.6% under an ultraviolet exposure for 180 min.