Many strategies exist on how to contribute to a better, or more specific performance of titania, for application in the wide area of photochemistry: electrosplitting, sensing, photovoltaic and photocatalytic performance. Regarding morphology, achieving advanced nano-architecture (oriented anatase nanotubes) may increase efficiency of the charge transfer by 30% or more. Therefore, we prepared nanostructured titania thin films comprising different levels of lateral and vertical microstructural order as well as surface chemistry by means of titanium anodization.
We described the films using electron microscopy, and synchrotron grazing incidence X-ray scattering/diffraction. To shed more light on the contributions, we introduced description of the film constituents to: top porous non-stoichiometric titania, mid tubular nanoformations, and bottom dense titania. Interestingly, among different tubular nanoformation films, those that were somewhat distorted were found to be better suited for the photo-degradation of salicylic acid (fitted with pseudo-second order kinetics).
We found the reasons behind the photodegradation are (in order of importance): most important was the evolution of type of porosity and presence of defects in the films; second the ratio and vertical profile of anatase-to-rutile and finally, the photodegradation was affected by the presence of substoichiometric titania. In conclusion, we showed that it was possible to control the evolution of the differently nanostructured titania in terms of lateral and vertical microstructural profiles, as well as chemical and crystal composition, for enhancing the photocatalyst performance.