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

Abstract

• DMS efficiently degraded by UiO-66@TiO 2 synthesized through a solvothermal method. • UiO-66 served as adsorbent, support and photocatalyst in UiO-66@TiO 2 composite. • Highest photodegradation efficiency of DMS observed at 60% relative humidity. • U1T3 showed advantageous photodegradation and cycling performance. • Photocatalytic mechanism and degradation kinetics of DMS were illustrated. The photocatalytic activity of titanium dioxide (TiO 2 ) for the purification of odour pollutants, containing reduced sulfur compounds (RSCs), could be largely improved by the coupling of porous materials. Herein, UiO-66@TiO 2 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), N 2 isotherms, and UV–vis DRS (diffuse reflectance spectra). The photodegradation performance of dimethyl sulfide (DMS) by synthesized UiO-66@TiO 2 was investigated under various photodegradation conditions, including photocatalyst dosage, DMS concentrations and relative humidity. The results showed that the U1T3 (UiO-66:TiO 2 = 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 TiO 2 , respectively. This indicates that the intimate contact interfaces between UiO-66 and TiO 2 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@TiO 2 nanocomposites could promote the practical applications of MOF-based photocatalysts for the degradation of DMS.