Synthesis of nanocrystalline TiO2 thin films by liquid phase deposition technique and its application for photocatalytic degradation studies

A transparent, high purity titanium dioxide thin film composed of densely packed nanometer sized grains has been successfully deposited on a glass substrate at 30°C from an aqueous solution of TiO2-HF with the addition of boric acid as a scavenger by liquid phase deposition technique. From X-ray diffraction measurement, the deposited film was found to be amorphous and turns crystalline at 500°C. The deposited film showed excellent adherence to the substrate and was characterized by homogeneous flat surface. TiO2 thin films can be used as a photocatalyst to clean up organohalides, a class of compound in pesticides that pollute the ground water. Photocatalytic degradation experiments show that indanthrene golden orange dye undergoes degradation efficiently in presence of TiO2 thin films by exposing its aqueous solution to ultraviolet light. The suitable surface structure and porosity increases the photocatalytic activity. It was also observed that hemin doped TiO2 thin films break up organohalides at a surprisingly high rate under visible light

Effects of Ni doping on photocatalytic activity of TiO(2) thin films prepared by liquid phase deposition technique

The TiO(2) thin films doped by Ni uniformly and non-uniformly were prepared on glass substrate from an aqueous solution of ammonium hexa-fluoro titanate and NiF(2) by liquid phase deposition technique. The addition of boric acid as an F(-) scavenger will shift the equilibrium to one side and thereby deposition of the film is progressed. The rate of the reaction and the nature of deposition depend on growing time and temperature. The resultant films were characterized by XRD, EDAX, UV and SEM. The result shows that the deposited films have amorphous background, which becomes crystalline at 500 degrees C. The EDAX data confirms the existence of Ni atoms in TiO(2) matrix. XRD analysis reveals the peaks corresponding to Ni but no peak of crystalline NiO was found. The transmittance spectra of Ni uniformly and non-uniformly doped TiO(2) thin films show 'blue shift and red shift', respectively. Ni-doped TiO(2) thin films can be used as photocatalyst for the photodegradation of methyl orange dye. It was found that, organic dye undergoes degradation efficiently in presence of non-uniformly Ni-doped TiO(2) thin films when compared to uniformly doped films and pure TiO(2) films under visible light. The photocatalytic activity increases with increase in the concentration of Ni in case of nonuniformly doped thin films but decreases with the concentration when uniformly doped thin films were used

Characterization and photocatalytic activity of boron-doped TiO(2) thin films prepared by liquid phase deposition technique

Boron doped TiO(2) thin films have been successfully deposited on glass substrate and silicon wafer at 30 degrees C from an aqueous solution of ammonium hexa-fluoro titanate and boron trifluoride by liquid phase deposition technique. The boric acid was used as an F(-) scavenger. The resultant films were characterized by XRD, EDAX, UV and microstructures by SEM. The result shows the deposited film to be amorphous which becomes crystalline between 400 and 500 degrees C. The EDAX and XRD data confirm the existence of boron atom in TiO(2) matrix and a small peak corresponding to rutile phase was also found. Boron doped TiO(2) thin films can be used as photocatalyst for the photodegradation of chlorobenzene which is a great environmental hazard. It was found that chlorobenzene undergoes degradation efficiently in presence of boron doped TiO(2) thin films by exposing its aqueous solution to visible light. The photocatalytic activity increases with increase in the concentration of boron

Synthesis and characterization of MoO3-WO3 composite thin films by liquid phase deposition technique: Investigation of its photochromic properties

In order to achieve high colouration efficiency, MoO3-WO 3 composite thin films have been successfully deposited on sodium silicate glass and silicon wafer (111) at 30 °C by a very simple novel wet process known as liquid phase deposition. The deposited films were annealed at different temperatures and characterized by carrying out SEM, EDAX, UV-vis and XRD analyses. The EDAX and SEM analyses support the structure and existence of peaks corresponding to Mo, W and O. X-ray diffraction studies showed that MoO3-WO3 is amorphous at lower temperature and turns crystalline at higher annealing temperature and suggested the mixture of two crystalline phases such as orthorhombic.monoclinic. Photochromic properties of the MoO3-WO3 composite films were studied in the spectral region 400-1200 nm by illuminating them in polychromatic light. The photochromic behaviour is observed to be more effective in composites films in visible region. © Indian Academy of Sciences