Vikas Sawant; D.A. Lavate; A.S. Khomane
Abstract
Aim of this work is to study the synthesis of CdS thin films by eco-friendly rout and analyze the change in structural and optical properties of material due to use of biomolecules as a stabilizing agent. The CdS thin films were deposited in lemon extract and ammonia solution separately by maintaining ...
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Aim of this work is to study the synthesis of CdS thin films by eco-friendly rout and analyze the change in structural and optical properties of material due to use of biomolecules as a stabilizing agent. The CdS thin films were deposited in lemon extract and ammonia solution separately by maintaining the same physical parameters and analyzed for tailoring of structural and optical properties. Green-CBD method minimizes the use of toxic precursors and volatilization of ammonia solution. X-Ray Diffraction study indicates formation of face centered cubic crystalline phase predominantly for CdS thin films materials with change in grain size. SEM analysis revealed the formation of CdS nanospheres in ammonia while CdS nanocubes in lemon extract. The direct allowed band gap energy was observed in the order of 2.45 eV and 2.25 eV which were interesting for optical studies. UV-Vis Absorption spectra and PL spectra of thin films indicates the CdS thin film material has absorption maxima in visible (400-800 nm) region. As synthesized CdS thin films were applied for photodegradation of Rhodamine-B dye solution under sunlight. The CdS thin film material deposited by Green-CBD rout shows high efficiency for degradation of Rhodamine-B solution as compared to films deposited by CBD method.
M. Mzoughi; William. W. Anku; Samuel O. B. Oppong; Sudheesh K. Shukla; Eric S. Agorku; Penny P. Govender
Abstract
Purification of industrial wastewater from dyes receiving increasing attentions. The aim of the present manuscript was to fabricate graphene based nanocomposites using a homogeneous and facile approach. Co-precipitation method was used to synthesize zirconium oxide (ZrO2) and neodymium doped ZrO2-graphene ...
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Purification of industrial wastewater from dyes receiving increasing attentions. The aim of the present manuscript was to fabricate graphene based nanocomposites using a homogeneous and facile approach. Co-precipitation method was used to synthesize zirconium oxide (ZrO2) and neodymium doped ZrO2-graphene oxide (Nd-ZrO2-GO) nanocomposites with varying weight percent concentrations of neodymium to investigate the increasing photocatalytic activity. The Nd-ZrO2-GO catalysts were characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (SEM), and ultra violet-visible (UV-vis)-spectroscopy to evaluate their optical, morphological and structural properties respectively. The photocatalytic degradation potential of the nanocatalyst was assessed by the degradation of Eosin Y dye in aqueous solution under simulated solar light irradiation. The Nd-ZrO2-GO was observed to have higher photocatalytic degradation potential than the bare ZrO2. The most efficient photocatalyst for the degradation of Eosin Y dye was 0.3 % Nd-ZrO2-GO with about 80 % efficiency within 180 min and a Ka value of 4.19 x 10 -3 . Nd-ZrO2-GO catalyst would be considered as efficient photocatalyst to degrade the industrial dyes (Eosin Y) avoiding the dreary filtration steps.
Ravinder Guje; G.Ravi;M. Vithal; J.R. Reddy; Ch. Sudhakar Reddy; K. Sreenu; G.Ravi and M. Vithal
Abstract
Materials belonging to defect pyrochlore structure have been the subject of considerable interest and expected to exhibit fast protonic conduction. The proton exchanged ternary metal oxides of composition HM0.33Te1.67O6 (M = Al, Cr and Fe) are prepared for the first time by ion exchange method at room ...
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Materials belonging to defect pyrochlore structure have been the subject of considerable interest and expected to exhibit fast protonic conduction. The proton exchanged ternary metal oxides of composition HM0.33Te1.67O6 (M = Al, Cr and Fe) are prepared for the first time by ion exchange method at room temperature. These materials are characterized by X-ray Diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and solid state NMR techniques. All the materials are crystallized in a cubic lattice with the Fd - 3m space group. Photocatalytic activity against methyl violet (MV) degradation under visible light irradiation is studied. The mechanistic degradation pathway of MV is studied by a fluorescence technique using terepthalic acid (TA) as a probe and Tertiary butanol (TB) as hydroxyl radical quencher. The dc conductivity of all three compositions is studied in the temperature range 300 – 673 K. The variation of dc conductivity with temperature is explained.
Husien A. Abbas; Tarek S. Jamil
Abstract
Nano-sized SrTiO3 and SrTi0.7Fe0.3O3 photocatalysts were prepared by the complex route precursor method. The prepared photocatalysts were characterized by XRD, TEM, XPS and diffuse reflectance. The effect of iron doping on the structural properties and the photocatalytic activity was studied. All the ...
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Nano-sized SrTiO3 and SrTi0.7Fe0.3O3 photocatalysts were prepared by the complex route precursor method. The prepared photocatalysts were characterized by XRD, TEM, XPS and diffuse reflectance. The effect of iron doping on the structural properties and the photocatalytic activity was studied. All the prepared samples have single cubic perovskite structure. It was found that doping of SrTiO3 with Fe shifted the peak positions toward higher 2θ value, decreased both the cubic lattice parameter and the unit cell volume, decreased the average crystallite size of SrTiO3 from 53 nm to 35 nm and shifted the absorption to the visible light range (red shift). The photocatalytic degradation activity of 30 mole % Fe doped SrTiO3 was significantly improved the degradation of dibutyl phthalate in 90 minutes under visible light irradiation by 4 times higher than SrTiO3.
Omkar S. Kushwaha; C. V. Avadhani; R. P. Singh
Abstract
Acid doped polybenzimidazole membranes have emerged as an efficient electrolyte for high temperature polymer electrolyte membrane fuel cells (HTPEMFCs). The long term stability of polybenzimidazole membranes has been recognized as an important issue for commercial applications. Here, we report the oxidative ...
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Acid doped polybenzimidazole membranes have emerged as an efficient electrolyte for high temperature polymer electrolyte membrane fuel cells (HTPEMFCs). The long term stability of polybenzimidazole membranes has been recognized as an important issue for commercial applications. Here, we report the oxidative degradation of polybenzimidazole membranes. The photoirradiation of poly(2,2'-ethylene-5,5'-bibenzimidazole) (PBIE) under accelerated photodegradation conditions was carried out by ultraviolet (UV) rays (λ > 300 nm) and characterized by Fourier transform infra red (FT-IR) spectroscopy, scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and contact angle measurements (CAM). The thermal properties of PBIE membranes were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) which revealed a lowering in thermal stability after photodegradation. FT-IR spectra revealed high absorbance in the carbonyl region in photoirradiated membranes whereas SEM showed nano structures / defects on the polymer film surface. CAM results showed enhancement in hydrophilic behavior and WAXD revealed increase in amorphous nature upon irradiation.
Omkar S. Kushwaha; C. V. Avadhani; R. P. Singh
Abstract
High temperature polymer electrolyte membrane fuel cells (HTPEMFCs) are energy efficient systems with the potential to address all energy issues of present and future generations. Polybenzimidazole (PBI) based high temperature fuel cells are subject of high importance because PBI membranes are proved ...
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High temperature polymer electrolyte membrane fuel cells (HTPEMFCs) are energy efficient systems with the potential to address all energy issues of present and future generations. Polybenzimidazole (PBI) based high temperature fuel cells are subject of high importance because PBI membranes are proved to be one of the best candidates for high temperature fuel cell applications. The stability of PBI membranes has been identified as crucial issue for the long-term durability under oxidative conditions of fuel cells. The present investigation highlights the photo-oxidative degradation studies accomplished on polybenzimidazole based poly(2,2'-butylene-5,5'-bibenzimidazole) (PBIB) membranes. The PBIB polymer membranes are found suitable for both in high temperature fuel cells as well as other high temperature applications. In this research article, PBIB membranes were photoirradiated under polychromatic UV rays (λ > 290 nm). The photo-oxidative degradation of membranes was characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). FT-IR results showed significant amount of photo-oxidation and chemical degradation in fuel cell membranes which is proposed to be initiated by free radical mechanism. SEM images revealed development of nano-dimensional cracks and holes on surface of membranes which indicate structural and morphological degradation. The present study showed better results of accelerated photo-degradation as compared to the oxidative degradation results already reported in literature obtained chemically and thermally. Hence, the proposed photo-oxidative degradation method may be useful in determining stability, life time expectancy and degradation mechanism of fuel cell and other high performance membranes.