Solar Light Driven Supramolecular Photocatalysis by TiO2 and β-cyclodextrin

Solar light is the naturally available green and renewable energy source. This paper is aimed to investigate the mechanism of improving the photocatalytic ability of TiO2 using beta-cyclodextrin (beta-CD) beneath natural solar light to remove Metanil Yellow (MY) dye. The TiO2 beta-CD photocatalytic system has demonstrated higher photocatalytic activity for MY dye decolorisation. The operational parameters such as initial concentration of dye, dose of the catalyst, pH and illumination time were studied. The photocatalytic kinetic data were found to be in good agreement with pseudo-first order kinetics. The physicochemical characterization techniques viz., XRD, FT-IR and SEM were utilized to study the interaction of beta-CD with TiO2. The band gap energies of bare TiO2 and TiO2 beta-CD were calculated from UV-Diffused Reflectance Spectra (UV-DRS). The band gap energies were determined as 3.50 eV and 3.52 eV respectively, for bare TiO2 and TiO2 beta-CD. The photoluminescence spectrum of TiO2 beta-CD showed the decreased NBE intensity than bare TiO2. This has revealed that in TiO2 beta-CD system, the exciton recombination rate that usually decreases the efficiency of TiO2 photocatalytic activity has been reduced.