Photodegradation of Gaseous Toluene by the CdS/TiO2/ACFs Composites under Daylight Irradiation

To improve the photocatalytic application performances of TiO2, in this work, firstly CdS modified Degussa P25 TiO2 (CdS/TiO2) composites were prepared, then they were loaded on activated carbon fibers(ACFs) by dip-coating method. The composites were characterized by XRD, UV-vis, SEM, EDS and BET. Their photocatalytic activities under daylight were investigated by the degradation of gaseous toluene. The results showed that CdS/TiO2 composites mainly composed of anatase TiO2 and little CdS phases; CdS/TiO2 absorption edge had a pronounced “red shift”, the corresponding absorption edge wavelength of CdS/TiO2 composites were extended to 740 nm, respectively. From EDS spectrum, the main elements of CdS/TiO2/ACFs were Ti and O and a small quantities of S and Cd. CdS/TiO2 loaded on ACFs was in the form of small clusters, but not very uniform; compared with original ACFs, the surface area and pore volume of CdS/TiO2/ACFs decreased slightly, while the average size remained unchanged. The photodegradation rate of toluene by CdS/TiO2/ACFs composites under daylight irradiation was markedly higher than that by TiO2/ACFs, the maximal increasing rate reached as high as 18%.