DIRECT ULTRASONIC SYNTHESIS OF WO3/TiO2 NANOCOMPOSITES AND APPLYING THEM IN THE PHOTODECOLORIZATION OF EOSIN YELLOW DYE

This research reported a direct, environmentally friendly, economical, and simple method of using an ultrasonic instrument as a green technique to combine WO3 with TiO2 in ratios 0.5:1, 0.25:1, and 0.16:1 as composites 1, 2 and 3 respectively. Powder X-Ray Diffraction data identified the mean crystalline sizes of the commercial WO3, commercial TiO2, and of the prepared WO3/TiO2 nanocomposites in the different ratios in ranged from 17.897 nm to 48.672 nm. AFM analysis noted the surface morphology for all studied samples is spherical. The mean crystal sizes and practical sizes for prepared composites are found to be in the nanometer range, and these values rise with the raising in the TiO2 quantity in prepared nano-composites. The incorporated of W with Ti in the matrix is successful happened; because the ionic radius of W6+ is fewer values than it for Ti4+. The band gaps values for all samples have been investigated. The band gaps of prepared nanocomposites 1, 2, 3, and TiO2 are occurred as an indirect type, while the band gap of WO3 is found as direct type. The studied samples were tested by using them as photocatalysts in the decolorization of an aqueous solution, the eosin yellow dye Edecol.%. The sequence of decoloration grows from the left to the right as: Edecol.% (composite 3) Edecol.% (WO3) Edecol.% (TiO2) Edecol.% (composite 2) Edecol.% (composite 1). The activity of WO3 is inhibited with addition of H2O2 to the aqueous solution of eosin yellow dye because of the formation of peroxotungstic acid (WO3H2O2.H2O or WO2(O2)H2O.nH2O), but the modified surface by incorporation of TiO2, improves the activity hence, nano-composite 1 in the ratio of 0.5:1 is given a maximum photodecolorization efficiency of this dye and changed from 25.11% to 73.88%.

Electrochromic Properties of Lithium Vanadate Doped Tungsten Trioxide Film

Lithium vanadate doped tungsten trioxide films were coated on conducting fluorine doped tin oxide substrate by the sol-gel and dip coating methods using lithium vanadate and peroxotungstic acid sol. The concentration of lithium vanadatewas varied and the effects of lithium vanadate on morphology, microstructure and electrochromic properties of WO3 film were investigated. The synthesized tungsten trioxide with 10 wt.% lithium vanadate can be identified as amorphous structure. It observed that the crystallinity of the films are increase and more smooth when Li concentration increased and exhibits excellent properties in electrochromic performance in terms of diffusion coefficient is about as 2.6×10-9 cm2s-1 with the potential scan from -1.0 to +1.0 V as a scan rate of 100 mVs-1 in 0.5 M H2SO4 solution.

Scalable one-step synthesis of TiO2/WO3 films on titanium plates with an efficient electron storage ability

This study describes a new scalable method to prepare TiO2/WO3 film electrodes with an efficient electron storage ability through one-step oxidation of Ti plates in a mixture of H2O2 and peroxotungstic acid solution.

The Influences of Annealing Temperature on the Crystal Phase and Microstructure of the WO3 Thin Film

The tungsten oxideWO3thin film was prepared by sol-gel process through peroxotungstic acid (PTA). The crystal phase and surface morphological features change at different annealing temperatures. The WO3 thin film is amorphous at 300 °C. When the annealing temperature is increased to 400 °C, it becomes monoclinic phase. The phase begins to become triclinic at 550 °C. The phase then changes to orthorhombic phase at 750 °C. With the increasing of the annealing temperature, the continuum of the WO3 thin film is broke and the gabs among grains become larger. The WO3 thin film is almost disappear after annealed at 850 °C.

Effect of Templates on the Electrochromic Properties of Tungsten Oxide Thin Films

The mesoporous tungsten oxide (WO3) films were derived from the peroxotungstic acid (PTA) sol with templates through sol-gel method. Polyethylene glycol (PEG) 400 and tri-block polymer P123 (HO(CH2CH2O)20(CH2CH(CH3)O)70(CH2CH2O)20H) were chosen as templates. The structural, morphological, optical and electrochromic properties of the WO3 thin films derived from different sols were studied. The composition and crystal phase of the films change at different annealing temperatures. The films derived from the sols containing templates have higher crystallization temperature than those without templates. And the morphologies are distinctly different from different sols. The addition of the templates can improve the electrochromic properties of the WO3 films, and those prepared from the 3% of P123 sol show the best electrochromic properties. The highest transmittance modulation is near 60%, and the largest ion inserted and deinserted diffusion coefficient can reach 5.706×10-12 cm2/s and 1.271×10-11 cm2/s, respectively.