A convenient approach of MIP/Co–TiO2 nanocomposites with highly enhanced photocatalytic activity and selectivity under visible light irradiation

Abstract

Molecular imprinted polymer coated Co-doped TiO₂ nanocomposites (MIP/Co–TiO₂ nanocomposites) were successfully synthesized by a surface molecular imprinting technique using rhodamine B (RhB) as the template molecule and p-phenylenediamine as the functional monomer. The surface structure and properties of the nanocomposite catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption/desorption measurements (BET) and UV-vis diffuse reflectance spectra (UV-vis DRS). The preferentially selected degradation and activity of imprinted photocatalysts were evaluated by degradation of the template molecule RhB relative to rhodamine 6G (Rh6G) under visible light irradiation. Compared with the non-imprinted Co-doped TiO₂ nanocomposites (NIP/Co–TiO₂ nanocomposites), the MIP/Co–TiO₂ nanocomposites exhibited higher photo-degradation rate for RhB and also showed enhanced selective activity for RhB. The k value for the photodegradation of RhB over MIP/Co–TiO₂ nanocomposites was 0.03606 min⁻¹, being 215.7% that of RhB over NIP/Co–TiO₂ nanocomposites (0.01672 min⁻¹) and 337.3% that of RhB over Co–TiO₂ nanoparticles (0.01069 min⁻¹). The k value for the photodegradation of RhB over MIP/Co–TiO₂ nanocomposites was 0.03606 min⁻¹, being 150.5% that of Rh6G over MIP/Co–TiO₂ nanocomposites (0.02396 min⁻¹). Moreover, the MIP/Co–TiO₂ nanocomposites exhibited high stability and reusability.