Oxidative Degradation of Organic Pollutants by a New Hybrid Titania Based Gel-Derived Material with Stable Radical Species

Abstract

A TiO₂–based hybrid material (HSGT), obtained by a sol–gel route wholly performed in air at room temperature, was used as catalyst for the oxidative degradation of 2,4-dichlorophenol (2,4-DCP), 4- chlorophenoxyacetic acid (4-CPA) and phenanthrene (PHE). Acetylacetonate ligands, used as complexing/sensitizing molecules, was added directly to the solution containing the precursors of titanium. In the presence of air, the acetylacetonate ligands on the HSGT surface were able to generate stable superoxide radicals, as demonstrated by EPR measurements. The presence of superoxide radicals correlated to the catalytic activity of HSGT. ThDue to the stability of the free radicals, HSGT can be considered a promising catalyst for the degradation of organic pollutants.