Assembling UiO-66@TiO2 nanocomposites for efficient photocatalytic degradation of dimethyl sulfide

Abstract The photocatalytic activity of titanium dioxide (TiO2) for the purification of odour pollutants, containing reduced sulfur compounds (RSCs), could be largely improved by the coupling of porous materials. Herein, UiO-66@TiO2 nanocomposites with different blending ratios were synthesized via a readily solvothermal method and characterized experimentally by XRD (X-ray diffraction), SEM (scanning electron microscope), FTIR (Fourier transform infrared spectrum), N2 isotherms, and UV-vis DRS (diffuse reflectance spectra). The photodegradation performance of dimethyl sulfide (DMS) by synthesized UiO-66@TiO2 was investigated under various photodegradation conditions, including photocatalyst dosage, DMS concentrations and relative humidity. The results showed that the U1T3 (UiO-66:TiO2=1:3) composites exhibited the highest photocatalytic activity, which was about 17.8 and 7.1 times higher than that of pristine UiO-66 and TiO2, respectively. This indicates that the intimate contact interfaces between UiO-66 and TiO2 could promote the separation and migration efficiency of photogenerated electron-hole pairs. When relative humidity increased from 0% to 60%, the photocatalytic activity was enhanced because the moisture could assist to produce more hydroxyl radicals. However, when the relative humidity was further increased to 90%, the excessive water would compete with DMS on the surface of UiO-66 and subsequently weaken the photocatalytic effects. During the cycling experiments, U1T3 showed a stable photocatalytic performance, and the plausible photocatalytic reaction mechanism and reaction pathways of DMS were proposed. With a significant enhancement of photocatalytic performance, UiO-66@TiO2 nanocomposites could promote the practical applications of MOF-based photocatalysts for the degradation of DMS.