Enhancing the photocatalytic degradation of salicylic acid by using molecular imprinted S-doped TiO2 under simulated solar light

Molecular imprinted polymer coated S-doped TiO2 (MIP/S-TiO2) nanocomposites were successfully synthesized by a surface molecular imprinting technique using p-phenylenediamine as the functional monomer and salicylic acid as the template molecule. The structure and properties of the catalysts were characterized by X-ray diffraction, scanning electron microscopy, and UV–vis diffuse reflectance spectra. Compared with TiO2 nanoparticles, the absorption edge of MIP/S-TiO2 nanocomposites was enhanced over the whole range of visible region. Moreover, MIP/S-TiO2 nanocomposites showed higher adsorption capacity for salicylic acid than for S-TiO2 nanoparticles. The rate constant for the photodegradation of salicylic acid over MIP/S-TiO2 nanocomposites was 1.7 times that of salicylic acid over S-TiO2 nanoparticles, which was attributed to the molecular recognition ability of MIP/S-TiO2 nanocomposites for the target molecules.