Dye degradation studies of Mo-doped TiO2 thin films developed by reactive sputtering

Abstract

TiO2 thin films with various Mo concentrations have been deposited on glass and n-type silicon (100) substrates by this radio-frequency (RF) reactive magnetron sputtering at 400 degrees C substrate temperature. The crystal structure, surface morphology, composition, and elemental oxidation states of the films have been analyzed by using X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. Ultraviolet-visible spectroscopy has been used to investigate the degradation, transmittance, and absorption properties of doped and undoped TiO2 films. The photocatalytic degradation activity of the films was evaluated by using methylene blue under a light intensity of 100mWcm(-2). The X-ray diffraction patterns show the presence of anatase phase of TiO2 in the developed films. X-ray photoelectron spectroscopy studies have confirmed that Mo is present only as Mo6+ ions in all films. The Mo/TiO2 band gap decreases from similar to 3.3 to 3.1eV with increasing Mo dopant concentrations. Dye degradation of similar to 60% is observed in Mo/TiO2 samples, which is much higher than that of pure TiO2.