The application of TiO2@UiO-66-(OH)2 composites for the photocatalytic degradation of gaseous formaldehyde under visible light

Photocatalysts TiO 2 @UiO-66-(OH) 2 was successfully synthesized via an impregnation method for removal of formaldehyde under high pressure mercury lamp irradiation, and the photocatalysts were characterized by using a variety of analytical techniques. The characterized results indicated that TiO 2 was attached to the surface of UiO-66-(OH) 2 , and there was a strong electronic interaction between the elements of TiO 2 and UiO-66-(OH) 2 in the composite. The synergistic combination of high adsorption capacity of UiO-66-(OH) 2 , high dispersion of TiO 2 and efficient interfacial charge transfer between UiO-66-(OH) 2 and TiO 2 have a significant impact on the enhanced photocatalytic performance for formaldehyde removal. And the hydroxyl radicals (⋅OH) and superoxide radicals (⋅O 2 − ) also play a major role in removal of formaldehyde. The formaldehyde removal rate of 20TiO 2 @UO (1 g 0.15 m 3 ) is 83.01 % within 5.5 h, if the removal time is extended to 24 h, the formaldehyde removal rate can reach 91.49 %, and the continuous photocatalytic reaction showed that the composite is a highly stable catalyst. This could provide a useful method for highly efficient formaldehyde in indoor air purification.