Highly Characteristic Adsorption Based on Single Crystal {001}-TiO₂ Surface Molecular Recognition Promotes Enhanced...

Exploring the adsorption and selective removal mechanism of target pollutants on the catalytic interface is an important research topic in the field of environmental sewage treatment. However, the molecular recognition based on the surface of single crystals is still unclear. Single crystal molecularly imprinted TiO₂ (001-MI-TiO₂) with a highly exposed {001} plane was prepared by a hydrothermal method to characteristically adsorb and degrade phenol. The kinetics of phenol oxidation on 001-MI-TiO₂ was 12.93 times that of polycrystal nonimprinted TiO₂. The phenol adsorption quantity of 001-MI-TiO₂ was 1.68 times that of the polycrystal molecularly imprinted TiO₂ (MI-TiO₂). Compared with MI-TiO₂, the significantly increased removal of phenol on 001-MI-TiO₂ mainly attributed to the enhanced adsorption quantity and better photocatalytic performance. The recognition mechanism of phenol on the 001-MI-TiO₂ during the adsorption process was studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), which indicated enhanced adsorption of phenol when compared with MI-TiO₂. The recognition between the phenol molecule and the imprinted sites mainly relied on the hydrogen bond between the π bond of the benzene ring and the hydroxyl group on the surface of TiO₂. Besides, the interferent ATR-FTIR results showed that the single crystal surface can significantly reduce noncharacteristic adsorption, indicating good selectivity for the targets. In addition, the degradation intermediates during the photocatalytic process were further analyzed by in situ infrared technology.