Investigating the photocatalytic degradation property of Pt, Pd and Ni nanoparticles-loaded TiO 2 nanotubes powder prepared via rapid breakdown anodization.

The present study was performed to investigate the photocatalytic efficiency of the titania (TiO2 ) nanotubes (NTs) powder prepared via rapid breakdown anodization sensitized individually with Ni, Pd and Pt metal nanoparticles (NPs). The TiO2 NTs powder had the length of 5-6 μm, with the outer diameter between 20 and 25 nm and the wall thickness of 3-4 nm as observed in the scanning and transmission electron microscopes. The crystal structure analysis employing X-ray diffraction indicated the presence of Pt, Pd and Ni NPs in face-centered cubic phase over the anatase TiO2 NTs powder. The photocatalytic degradation of methylene blue (MB) was carried out with these photocatalysts. As a result, the performance of the 2 at.% Pt-loaded Pt-TiO2 NTs nanocomposite was determined to be superior on comparison to other photocatalysts under the current investigation. Fourier-transform infrared spectra confirmed the absence of any adsorption of MB or degraded products onto the surface of all the photocatalysts. The electron paramagnetic resonance analysis substantiated the e- transfer interaction from the conduction band of TiO2 NTs to Fermi level of Pt NPs has resulted in the better photodegradation process. The possible degradation mechanism using Pt-TiO2 NTs nanocomposites is discussed.