Controlled deposition and enhanced visible light photocatalytic performance of Pt-modified TiO2 nanotube arrays.

Highly ordered TiO 2 nanotube arrays (TiO 2 NTAs) have been fabricated by the potentiostatic anodization method with Ti foils. Pt nanoparticles have been successfully deposited onto TiO 2 NTAs by UV light photoreduction method. In this work, X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy and energy dispersive X-ray spectrometer methods were adopted to characterize the samples. The influence of different concentration of H 2 PtCl 6 precursor solution on the morphology and photocatalytic performances of samples was discussed. The SEM observations showed that Pt nanoparticles distributed on the wall of TiO 2 nanotubes uniformly. UV–vis spectra analysis showed that the light absorption of Pt/TiO 2 NTAs has been extended to the visible light range. When the concentration of H 2 PtCl 6 was 3 mM, the prepared sample showed the highest photodegradation rate. After irradiated under visible light for 2 h, the degradation rate of methyl orange solution reached 84.27%. Under the same condition, no obvious photodegradation of methyl orange was found for TiO 2 NTAs. Kinetic research showed that photodegradation process followed the first-order reaction, the apparent reaction rate constant of 3 Pt/TiO 2 NTAs was 1.493 × 10 −2 min −1 . [ABSTRACT FROM AUTHOR]