Loading effect of Ag nanoparticles on photocatalytic activity of TiO₂ nanorod arrays prepared by hydrothermal method

Rutile-TiO₂ nanorod thin films were formed on Ti disks via alkali treatment in Naoh solutions followed by heat treatment at 700°C. Ag nanoparticles were loaded on nanorods using a photo-reduction method to improve the photocatalytic properties of the prepared specimen. The surface characterization and the photo-electrochemical properties of the Ag-loaded TiO₂ nanorods were investigated using a field-emission scanning electron microscope (Fe-Sem), X-ray photoelectron spectroscopy (XPS), uV-Vis spectroscopy and electrochemical impedance spectroscopy (eiS). The TiO₂ nanorods obtained after the heat treatment were 80 to 180 nm thick and 1 μm long. The thickness of the nanorods increased with the NaOH concentration. The UV-Vis spectra exhibit a shift in the absorption edge of the Ag-loaded TiO₂ to the visible light range and further narrowing of the bandgap. The decrease in the size of the capacitive loops in the eiS spectra showed that the Ag loading effectively improved the photocatalytic activity of the TiO₂ nanorods.