Sol–Gel Synthesis and characterization of hybrid TiO2-acetylacetonate materials

A series of TiO2-based hybrid inorganic–organic materials was synthesized by sol–gel and characterized by thermal and spectroscopic techniques. The xerogels have an amorphous structure, with part of Ti4+ ions stably coordinated to acetylacetonate ligands. Ligand-to metal charge transfer results in an extended light absorption in the visible range, with a significant reduction of the band gap compared to the reference TiO2. The hybrid structure is also related to the unusual presence of superoxide radical anions stably adsorbed on the materials surface. These properties make the studied materials active in the degradation of organic pollutants: their catalytic efficiency was tested in the removal of 2,4-dichlorophenol from water without light irradiation.