Preparation of nanosized TiO2/ZnO composite catalyst and its photocatalytic activity for degradation of methyl orange

The shape and size of TiO2/ZnO composite nanoparticles can be manipulated by introducing surfactants and different Zn/Ti(OBu)4 molar ratios during the synthesis process. Different sizes of spherical TiO2/ZnO composite nanoparticles are obtained when sodium dodecyl benzene sulfonate (DBS) and different Zn/Ti(OBu)4 molar ratios are used. Cubic TiO2/ZnO composite nanoparticles, hexagonal nanorods, and nanobelts are obtained when sodium dodecyl sulfonate (SDS) and different Zn/Ti(OBu)4 molar ratios are used. The XRD study shows that there is no obvious difference in crystal composition of various shapes of TiO2/ZnO composite nanoparticles. The photocatalytic degradation of methyl orange shows significant variation in rate that decreases in the order: TiO2/ZnO composites >TiO2 (with surfactant but no Zn) >TiO2 (without surfactant and Zn). An optimal Zn/Ti(OBu)4 molar ratio of 0.25:1 is found to achieve the highest photocatalytic activity of TiO2/ZnO composite nanoparticles.