Urea- and Cetyltrimethyl Ammonium Bromide-Assisted Hydrothermal Synthesis of Mesoporous Enzyme-Like Molecularly Imprinted TiO2 Nanoparticles with Molecular Recognitive Photocatalytic Activity

Using CTAB and urea as structure-directing agents, we synthesized mesoporous enzyme-like molecularly imprinted TiO2 nanoparticles with molecular recognitive photocatalytic ability by hydrothermal method. Adopting 4-nitrophenol as target pollutant, we found that the adsorption capacity of enzyme-like molecularly imprinted TiO2 for 4-nitrophenol is about three times that of the corresponding non-imprinted TiO2 (control TiO2), and the enzyme-like molecularly imprinted TiO2 shows a relative selectivity coefficient of 3.645. Moreover, the mesoporous enzyme-like molecularly imprinted TiO2 exhibits molecular recognitive photocatalytic activity for 4-nitrophenol under simulated solar light irradiation. The uniqueness of enzyme-like molecularly imprinted TiO2 is attributed to the geometric and chemical complementation between the target molecules and "imprinted cavities" of enzyme-like molecularly imprinted TiO2 nanoparticles. The results indicate that the convergence of molecular imprinting technology and mesoporous structure is powerful basis for the construction of efficient photocatalysts that are highly selective towards a particular organic pollutant.