Surface Properties and Photocatalytic Activity of KTaO(3), CdS, MoS(2) Semiconductors and Their Binary and Ternary Semiconductor Composites

Single semiconductors such as KTaO(3), CdS MoS(2) or their precursor solutions were combined to form novel binary and ternary semiconductor nanocomposites by the calcination or by the hydro/solvothermal mixed solutions methods, respectively. The aim of this work was to study the influence of preparation method as well as type and amount of the composite components on the surface properties and photocatalytic activity of the new semiconducting photoactive materials. We presented different binary and ternary combinations of the above semiconductors for phenol and toluene photocatalytic degradation and characterized by X-ray powder diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) specific surface area and porosity. The results showed that loading MoS(2) onto CdS as well as loading CdS onto KTaO(3) significantly enhanced absorption properties as compared with single semiconductors. The highest photocatalytic activity in phenol degradation reaction under both UV-Vis and visible light irradiation and very good stability in toluene removal was observed for ternary hybrid obtained by calcination of KTaO(3), CdS, MoS(2) powders at the 10:5:1 molar ratio. Enhanced photoactivity could be related to the two-photon excitation in KTaO(3)-CdS-MoS(2) composite under UV-Vis and/or to additional presence of CdMoO(4) working as co-catalyst.