Photosensitization of TiO2 P25 with CdS Nanoparticles for Photocatalytic Applications

Abstract

A TiO2/CdS coupled system was prepared by mixing the TiO2 P25 with CdS synthesized by means of the precipitation method. It was found that the specific surface area (SSA) of both components is extremely different and equals 49.5 for TiO2 and 145.4 m2·g−1 for CdS. The comparison of particle size distribution and images obtained by means of transmission electron microscopy (TEM) showed agglomeration of nanocomposites. X-ray diffraction (XRD) patterns suggest that CdS crystallizes in a mixture of cubic and hexagonal phases. Optical reflectance spectra revealed a gradual shift of the fundamental absorption edge towards longer wavelengths with increasing CdS molar fraction, which indicates an extension of the absorption spectrum of TiO2. The photocatalytic activity in UV and UV-vis was tested with the use of methyl orange (MO). The Langmuir–Hinshelwood model described well the photodegradation process of MO. The results showed that the photocatalytic behaviour of the TiO2/CdS mixture is significantly better than that of pure nanopowders.

Keywords

• semiconductors
• X-ray diffraction
• transmission electron microscopy (TEM)
• catalytic properties
• optical properties