Photocatalytic activity of TiO2 nanorods, nanowires and nanoflowers filled with TiO2 nanoparticles

This study establishes the feasibility to enhance the photocatalytic activity of nanostructured TiO2 thin films through embedding the free spaces with sol-gel TiO2 nanoparticles. With the various additives in the aqueous H2O2 solutions, thin films of TiO2 nanorods, nanowires, and nanoflowers were precipitated on metallic Ti substrates via the Ti-H2O2 interactions at 80 °C for 72 h. About 3-7% anatase TiO2 nanoparticles were then embedded successfully among the free spaces of the nanostructures by immersing them into a titania sol followed by lifting up with an appropriate withdrawing speed. When utilized to assist degradations of phenol in water under UV light illumination, the photocatalytic activity for thin films of nanorods and nanowires after filling with sol-gel TiO2 nanoparticles is 76% and 136% higher than that of the pristine films, respectively. The films also exhibited high stability upon cycling tests, which could thus find potential applications in wastewater treatments.