Studying the governing factors on the photo(electro)catalytic activity of surface-modified photocatalysts under visible light illumination

The nature of the interaction at the interface of dye molecules and TiO2 surface has paramount importance in their photosensitization properties for photo(electro)catalytic application. To address this issue, two groups of organic molecules i.e., catechol and salicylic derivatives were used for the surface modification of titania. These hybrid materials were then thoroughly analyzed employing XRD, SEM, UV-Vis, FTIR, Raman, and impedance spectroscopies. The photoactivity was studied using the photoelectrochemical analysis and photocatalytic hy-droxylation of terephthalic acid. Moreover, applying principal component analysis on Raman spectra indicated a significant change in the bond strength of Ti-O (B1g band) as a consequence of the chemical bond of adsorbed dye. This study links the nature of the interaction of dye and titania and the photoactivity of materials, which is thoroughly discussed in the presented work.