Study of Photocatalytic Behavior of Photochemical Doped TiO2 Nanoparticles with In-V Synthesized by Sol-Gel and Hydrothermal Methods

Indium- vanadium doped with different molar percent (0.05-1%) was prepared by photochemical reduction method on pure TiO2 nanoparticles synthesized by sol –gel and hydrothermal process. XRD, FT-IR, TEM, SEM and EDX analysis were done for characterized nanoparticles and methyl orange (MO) was used as an environmental pollutant to verify photocatalytic effect of synthesized particles under visible and UV lamps. Result of tests was showed that In-V doping restrain from crystal growth, that only hydrothermal TiO2 particles with binary doped 0.2% molar of In-V can improve photocatalytic activity compared to solgel nanoparticles. Pure TiO2 prepared by hydrothermal and sol-gel processes were calcined at 300,400,450,550 ºC for 3h and 500º C for 2h, respectively. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3528

Effect of large TiO 2 Nanoparticles as Light Scatter in Matrix of Small Nanoparticles to Improve the Efficiency in Dye- Sensitized Solar Cell

Abstract In this study, we investigated the effect of using large TiO 2 nanoparticles in the matrix of small nanoparticles to improve the performance of dye-sensitized solar cells (DSSCs), as light scatter to increase the light harvesting. The mixed powder was deposited by electrophoretic deposition (EPD) on FTO (F-SnO 2 coated glass). It is shown that adding small quantity of larger nanoparticles can enhance the performance of DSSCs. This paper also studies the deferential scanning calorimetry (DSC) of mixed powders to detect the phase transitions, due to the change of weight percentage between large and small nanoparticles. JNS All rights reserve

Electronic Structures of Cu/S Co-doped/Anatase TiO 2 by First-principles

ABSTRACT The structural parameters, band structures and density of states of anatase TiO2 co-doped with Cu and S were calculated by first-principles based on the density functional theory. The results indicate that the volumes of the co-doped TiO2 increase due to the lattice distortion. The calculated X-ray diffraction pattern shows that the crystal phase of TiO2 is still kept as anatase after Cu and S co-doping. The band gap of TiO2 broadened when S substitutes for Ti or O along with Cu substitutes for Ti. The calculated partial density of states shows that the impurity energy levels mainly come from the Cu 3d and S 3p orbital. The calculated results may provide some theoretical foundations for the photocatalytic activity enhancement of TiO2 co-doped with Cu and S

The Role of Solution and Coagulation Temperatures in Crystalline Structure, Morphology, Roughness, Pore Diameter Distribution, and Separation Properties of Nanoporous Membranes Fabricated Via Phase Inversion

In this study, fabrication of poly(vinylidene fluoride) (PVDF) flat sheet membranes and correlation of membrane morphology, roughness, crystalline structure, and pore diameter distribution as functions of coagulant temperature (T C) and precursor-solution preparation temperature (T S) in the phase inversion (PI) process of PVDF-DMF-H 2O mixture with 20wt of PVDF concentration was investigated. The results demonstrated that membranes have a typical asymmetric structure with a dense skin top layer and a porous substructure. An increasing amount of macrovoids was observed in the membrane substructure when T S is decreased. It was found that at lower T C, the membrane solution precipitated into a uniform morphology composed of spherical crystallites that exhibited the β-form crystal structure. By contrast, when PVDF was precipitated at higher temperatures, the formed membrane became largely in the α-form crystal structure. The pore size was estimated by Barett-Joyner-Halenda (BJH) method, ranging from 15 nm to tenth of hundred nm, depending on T C. The performance of the prepared membranes has been tested by the measure the effects of T C and T S on the separation characteristic of nanoporous PVDF membranes. We observed that the removal of Acid Yellow 23 (AY23) decreases as T S increases and extremely high dye removal efficiency of 99.37 was achieved. © 2012 Copyright Taylor and Francis Group, LLC

Influence of PVDF concentration on the morphology, surface roughness, crystalline structure, and filtration separation properties of semicrystalline phase inversion polymeric membranes

This study was focused on the fabrication of nanoporous poly(vinylidene fluoride) (PVDF) membranes at different polymer concentration (14, 17, and 20 wt) via phase inversion method. The morphology and surface roughness of the resulting membranes were investigated by scanning electron microscopy (SEM) and atomic force microscope, respectively. SEM results showed that with the increase of polymer concentration, the pore size of membranes and the overall porosity decrease. Also, the results showed that varying concentration results in significant changes on the surface roughness. Analysis of the crystalline structures of PVDF membranes by X-ray diffraction showed that the membranes, which precipitated in the higher concentration of polymer (20 wt) had a typical "β" form of the crystalline phase, whereas those membranes that formed at lower concentration (14 wt) showed crystallites of the "α + β" form of the crystalline phase. Furthermore, the filtration separation experiments of Acid Yellow 23 (AY23) were conducted to examine the effects of concentration parameter on the performance of nanoporous PVDF membranes. Results showed that the retention of AY23 increases as the polymer concentration increases and an efficiency of 89.72 was achieved in polymer concentration of 20 wt. © 2012 Desalination Publications. All rights reserved