Construction of covalently integrated core-shell TiO2 nanobelts@COF hybrids for highly selective oxidation of alcohols under visible light

Encapsulation of TiO2 nanobelts into crystalline and porous covalent organic frameworks materials to form a core-shell structure can enhance reactivity, selectivity and durability of photocatalysts distinctly. In this work, a range of TiO2 nanobelts@COF nanocomposites with different thicknesses of COF shell were fabricated via a novel and facile seed growth method. The results of photooxidation of benzyl alcohol under visible light ( > 420 nm) showed that TiO2 @COF-3 with COF shell thickness of around 15 nm showed the highest conversion (92.5%) with the maximum rate constant (6.73 x 10(-2) h(-1)), which is approximately 10.1 times as that of TiO2 and 12.9 times as that of COF. The enhanced photocatalytic activity of hybrid materials was mainly owing to the improved photon adsorption ability and charge carriers transfer from COF to TiO2. In addition, TiO2 @COF-3 still showed relatively high stability after 5 cycles under the same reaction condition. Therefore, this type of hybrid photocatalysts possesses great potentials in future green organic synthesis.