Anatomy of a Natural
Sunlight Driven CdS/CoTiO3/ZnO Ternary Photocatalyst for Efficient Optical Properties
and Removal of Reactive Orange 30
Divya G., Sakthi D., Priyadharsan A., Boobas S. and Sivakumar S.
Res. J. Chem. Environ; Vol. 25(8); 100-109;
doi: https://doi.org/10.25303/258rjce100109; (2021)
Abstract
ZnO as a promising photocatalyst has gained much attention for the removal of organic
pollutants from water. However, the main drawbacks of the relatively low photocatalytic
activity and high recombination rate of photoexcited electron-hole pairs restrict
its potential applications. Promoting the spatial separation of photoexcited charge
carriers is of paramount significance for photocatalysis because the difference
in the band positions makes the potential gradient at the composite boundary. In
this work, binary CdS/ZnO and CoTiO3/ZnO are first prepared by dispersion method
and then decorated with ZnO particles to construct CdS/CoTiO3/ZnO ternary composites.
For this reason, the CdS/CoTiO3/ZnO ternary composites was effectively designed
and analyzed for the crystalline structure, light absorption, photoexcitation behavior
and surface morphological properties by X-ray diffraction, diffuse reflectance UV/visible
absorption spectroscopy, photoluminescence spectroscopy and scanning electron micrograph
respectively.
The photocatalytic activity was examined by degradation of the dye solution spectrophotometrically.
The results of photocatalytic degradation indicated that the CdS/CoTiO3/ZnO ternary
composites are much higher than those of bare CdS, CoTiO3, ZnO and any binary composites
such as CoTiO3/ZnO and ZnO/CdS. The enhanced activity could be attributed to the
drop electron transfer from CdS to ZnO to CoTiO3 through the interfacial potential
gradient in the ternary hybrid conduction bands. The enhanced electron transfer
of CdS/CoTiO3/ZnO ternary composites was also applicable to degrade other reactive
dyes.
