Facile synthesis of N–F codoped and molecularly imprinted TiO2 for enhancing photocatalytic degradation of target contaminants

Abstract

N–F codoped and molecularly imprinted TiO2 (MIP-NFTs) were successfully prepared by simple ethanol–water solvothermal method using 2-nitrophenol (2NP) and 4-nitrophenol (4NP) as template molecules (target contaminants), respectively. The surface structure and properties of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption/desorption measurements (BET), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (UV–vis DRS). In comparison with non-imprinted N–F codoped TiO2 nanocomposites (NIP-NFTs), MIP-NFTs show a higher adsorption, good selectivity and preferable degradation capacity toward the target contaminants. The adsorption amounts of 2NP and 4NP over the corresponding MIP-NFTs are about 1.78 and 2.21 times of that over NIP-NFTs, respectively. MIP-NFTs show a much higher adsorption capacity and selectivity for target contaminants in the mixed solution. Degradation selectivity experiments demonstrate that the selectivity coefficient (R) of degradation of 2NP relative to 4NP over 2NP/MIP-NFTs and 4NP relative to 2NP over 4NP/MIP-NFTs are 1.93 and 1.61, respectively. The enhancement about adsorption capacity and selectivity can be attributed to the chemical interaction and size matching between target contaminants and imprinted cavities. The apparent rate constants for the photodegradation of 2NP and 4NP over the corresponding MIP-NFTs are 0.05233min−1 and 0.03734min−1, being 267% and 198% of that over NIP-NFTs under simulated solar light. Moreover, MIP-NFTs exhibit excellent reusability due to their inorganic framework.