TiO2 Nanotubes Transformation Into 4nm Anatase Nanoparticles

Abstract

The scope of this work shows novel experimental findings on preparing anatase TiO2 nanoparticles, first anodizing titanium into an organic media for obtaining TiO2 nanotubes, and using these as a photocatalytic active electrode in treating water polluted with organic contaminants. The substrates were grit blasted to obtain mechanical fixation of the generated nanotubular TiO2 structure. This was successfully achieved without diminishment of the nanotubes order and with a self-leveling of the outer surface. A new phenomenon has been investigated consisting of the process of oxidation of the nanotubes in water after anodizing. Along this process, methyl orange added to the aqueous solution was discolored as part of the redox reaction involved. The final state of the modified layer was composed of conglomerates of almost completely crystalline TiO2 nanoparticles, around 4 nm in size, consisting of anatase. SEM and TEM images show the transition of the amorphous nanotubes (atomic disorder/nanometric order) to crystalline disordered particles (atomic order/nanometric disorder).