Raviraj M. Kulkarni; Ramesh S. Malladi; Manjunath S. Hanagadakar
Abstract
Photocatalytic degradation of textile dye derivative Methyl Orange (M.O) has been studied in aqueous medium using 2% copper doped zinc oxide (2% Cu-ZnO) nanoparticles under UV irradiation. Simple inexpensive chemical precipitation method was used for synthesis of pure and copper doped zinc oxide nanoparticles. ...
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Photocatalytic degradation of textile dye derivative Methyl Orange (M.O) has been studied in aqueous medium using 2% copper doped zinc oxide (2% Cu-ZnO) nanoparticles under UV irradiation. Simple inexpensive chemical precipitation method was used for synthesis of pure and copper doped zinc oxide nanoparticles. The prepared nanoparticles pure and copper doped zinc oxide was characterized by X-ray Diffraction Technique (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis. The prepared nanoparticles were hexagonal wurzite structure. Photocatalytic efficiency of 2% Cu-ZnO were evaluated by studying mineralization of methyl orange (M.O.) as a model compound. The M.O. kinetics degradation was investigated under different parameters such as pH of the medium, catalyst dosage, M.O concentration, intensity of light etc. In addition reusability aspects of nanoparticles where also studied, which reveals that reused nanoparticles exhibited same results as that of virgin particles. Copyright © 2018 VBRI Press.
Mahlatse F. Manamela; Thuto E. Mosuang; Bonex W. Mwakikunga
Abstract
The mechano-chemical technique was employed to synthesise cobalt and indium single and double doped as well as the undoped ZnO nanopowder samples. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results confirm that the prepared samples were of hexagonal wurzite form. A new peak ...
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The mechano-chemical technique was employed to synthesise cobalt and indium single and double doped as well as the undoped ZnO nanopowder samples. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results confirm that the prepared samples were of hexagonal wurzite form. A new peak was observed in the diffraction pattern of the In doped ZnO nanopowders. Doping the ZnO nanoparticles with Co and In did not significantly affect the lattice parameters, even though the average grain sizes were found to be reduced. The morphology of the samples revealed by the scanning electron microscopy (SEM) images appear to be more spherical. The excitation wavelength of 350 nm was used in the photoluminescence (PL) study where various defects related emissions were observed for the doped and undoped ZnO nanoparticles. The energy band gap of the prepared samples was calculated from the ultraviolet-visible spectroscopy (UV-Vis) data. It was found that the doped ZnO nanoparticles had smaller energy band gap compared to the undoped ZnO nanoparticles. The Raman experiment were performed at the excitation wavelength of 514.532 nm and E2 (high) mode had the most intense peak. Copyright © 2018 VBRI Press.
Rajani Bharati; S. Suresh
Abstract
The aim of this research work is Synthesis of ZnO/SiO2 with Palash leaves extract nanocatalyst by green synthesis route. Palash leaves extract contain a broad variability of bio-molecules which act as capping and reducing agents and increases the rate of reduction and stabilization of nanoparticles. ...
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The aim of this research work is Synthesis of ZnO/SiO2 with Palash leaves extract nanocatalyst by green synthesis route. Palash leaves extract contain a broad variability of bio-molecules which act as capping and reducing agents and increases the rate of reduction and stabilization of nanoparticles. Nanocatalyst synthesized by this method are eco-friendly and cheap. No work has been found on Butea monosperma (Palash) leaves extract with ZnO nanoparticles. This research work synthesis of ZnO/SiO2 with palash leaves extracts nanocatalysts has been made by using green synthesis route. This synthesized nanocatalyst was used for removal of COD (mg/l) and polycyclic aromatic hydrocarbons as pollutants from petrochemical industrial wastewater. The synthesized nanocatalyst of ZnO/SiO2 with palash leaves extract was characterized using BET surface area, FEG-SEM, EDAX, XRD, and FTIR. Results show that we have synthesized ZnO/SiO2 nanocatalyst with BET surface area 160.23 m2/g and SEM micrograph shows the spot of nano range particles. From SEM test it has been found that we synthesized ZnO/SiO2 nanoparticles in the range of 3 to 35 nm and average particle diameter is 15.8nm. XRD and EDAX result show that we have found nanoparticles of SiO2 and ZnO. FTIR results show that Zn-O, Si-O-Si stretching have been found at 1004.95, 861.24 cm-1 for ZnO and 1270.17 cm-1 for SiO2 respectively. Results shows that optimum percent removal of COD (mg/l) and acenaphthene (polycyclic aromatic hydrocarbon) as pollutant are 70 % and 79% respectably at 0.5g/500ml catalyst loading, at 30oC temperature for 4h reaction time. In Future this catalyst can be used to remove other PAH and phenolic compounds from petrochemical wastewater under visible light also and other industrial wastewater can also treat by this catalyst effectively. Copyright © 2018 VBRI Press.
Pradosh K. Sahoo; G. Mangamma; M. Kamruddin; S. Dash; Ashok K. Tyagi
Abstract
In the present work ZnO dendritic nanostructures (NS) were synthesized by sol-gel and spin coating methods over silicon (100) substrate. The phase purity was confirmed by XRD. Grain size was found to be less than 10 nm. The vibrational modes of the nano ZnO wurtzite structure were observed by laser Raman ...
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In the present work ZnO dendritic nanostructures (NS) were synthesized by sol-gel and spin coating methods over silicon (100) substrate. The phase purity was confirmed by XRD. Grain size was found to be less than 10 nm. The vibrational modes of the nano ZnO wurtzite structure were observed by laser Raman spectroscopy. Raman spectra revealed asymmetrically broadened red shift of E2 (high) optical phonon mode which accrues from contribution of Non-Brillouin Zone (NBZ) phonons. The shift in the peak is attributed to the quantum mechanical confinement of phonon due to their nano grains as inferred from XRD and morphological studies by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). SEM and AFM images revealed the leaf like dendrite structures having several branches. Possible growth mechanism has been discussed in line with the synthesis. Box counting method was implemented to determine the fractal dimension (D) and the value of D is found to be ~1.6±0.1. This work will be useful in designing novel optoelectronic devices and sensors from ZnO nanostructures (NS) exhibiting complex morphology. Copyright © 2017 VBRI Press.
Mohd A. Ansari; Daipayan Dasgupta; K. Sreenivas
Abstract
Ultraviolet (UV) light detection characteristics with sputtered ZnO films deposited on paper with graphite pencil drawn conducting inter-digital electrodes on normal paper have been investigated. Structural, electrical and microstructural properties of ZnO films grown by magnetron sputtering ...
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Ultraviolet (UV) light detection characteristics with sputtered ZnO films deposited on paper with graphite pencil drawn conducting inter-digital electrodes on normal paper have been investigated. Structural, electrical and microstructural properties of ZnO films grown by magnetron sputtering technique at under differentsputtering pressures have been evaluated forultraviolet (UV) light detection. Different types of paper used as substrate material, and the influence of their surface microstructure on the growth of ZnO film quality is examined.Films deposited on the fibrous paper are found to be polycrystalline, whereas the same films on dense glass substrates promote a c-axis oriented growth. The nucleation of sputtered ZnO films on paper is found to occur along the fine fibers of the paper and vary with sputtering pressure. Films grown at higher sputtering pressures (30 to 40 mTorr) in Ar/O2=50:50 are found to yield dense deposits. Pencil drawn inter- digital electrode structures on paper overlaid with 0.25 μm thick ZnO films exhibit reproducible photo response to ultraviolet (UV) light (= 365 nm), with low dark current. It’simportant for low prize and easy fabrication of optoelectronic foldable devices.Copyright © 2017VBRI Press
Suranjan Sikdar; Sutanuka Pattanayek; Tanmay K Ghorai
Abstract
The Bi2MoZnO7 nanocomposites have been successfully synthesized via co-precipitation and solid state method and followed by a low temperature calcinations treatment process. We find that such a Bi2MoZnO7 nanocomposite exihibits higher photoctatalytic activity and stability than Bi2MoO6, Bi2O3 and ZnO ...
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The Bi2MoZnO7 nanocomposites have been successfully synthesized via co-precipitation and solid state method and followed by a low temperature calcinations treatment process. We find that such a Bi2MoZnO7 nanocomposite exihibits higher photoctatalytic activity and stability than Bi2MoO6, Bi2O3 and ZnO towards the aqueous phase degradation of Rhodamine B (RhB) under visible light (420 nm < λ). The presence of Bi3+/Mo6+/Zn2+ ions in Bi2MoZnO7 and formation of defects in the lattice is believed to play an essential role in affecting the photoreactivity. The different types of active species scavengers are also play the photocatalytic process. The synthesized Bi2MoZnO7 nanocomposites were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), SEM, TEM, EDAX and IR techniques. The crystallite sizes, particle and grain sizes are 12±2, 5±1 and 100±5 nm, respectively. The rate of degradation of Rhodamine B by BMZ in aqueous phase is 7 times (40.70×10-3min-1) faster in comparison to pure Bi2O3/ZnO. Copyright © 2017 VBRI Press.
Amit Srivastava; Naresh Kumar
Abstract
Biosensor for the detection of hydrogen peroxide (H2O2) has been prepared by immobilizing horseradish peroxidase (HRP) enzyme using physical adsorption technique on zinc oxide (ZnO) nanostructures. The (002) oriented ZnO nanostructures as confirmed by X-ray diffraction, were successfully grown on indium ...
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Biosensor for the detection of hydrogen peroxide (H2O2) has been prepared by immobilizing horseradish peroxidase (HRP) enzyme using physical adsorption technique on zinc oxide (ZnO) nanostructures. The (002) oriented ZnO nanostructures as confirmed by X-ray diffraction, were successfully grown on indium tin oxide (ITO) coated glass substrate by pulsed laser ablation (PLA) without using any catalyst. The Nafion solution was added onto HRP/ ZnO/ ITO bio-electrode to form a tight membrane on the surface before carrying out bio-sensing measurements by electrochemical analyzer. The electrochemical studies reveal that the prepared bio-electrode HRP/ZnO/ITO is highly sensitive to the detection of H2O2 over a wide range of concentration with a linear range from 2.5 μM to 100 μM with the limit of detection 0.2 μM and sensitivity of 0.034 µA/ µM cm2. The higher sensitivity attributed to larger surface area of ZnO nanostructure for effective loading of HRP besides its high electron communication capability. A relatively low value of the enzyme’s kinetic parameter (Michaelis-Menten constant, Km) of 0.166 μM indicates enhanced enzyme affinity of HRP to H2O2. The reported biosensor may be useful for various applications in bio-sensing, clinical, food and beverage industry.
Shrisha B V; Shashidhara Bhat; Parvathy Venu M; Dushyant Kushavah; K Gopalakrishna Naik
Abstract
Zinc Oxide (ZnO) nanowires (NWs) were grown on p-silicon (p-Si) substrates coated with around 10 nm thick metal films of Au, Al and Cu using vapor phase transport growth method. The effect of these metal catalysts and the substrate temperatures on the morphologies of ZnO NWs were studied using ...
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Zinc Oxide (ZnO) nanowires (NWs) were grown on p-silicon (p-Si) substrates coated with around 10 nm thick metal films of Au, Al and Cu using vapor phase transport growth method. The effect of these metal catalysts and the substrate temperatures on the morphologies of ZnO NWs were studied using field emission scanning electron microscopy (FESEM). The growth of ZnO NWs with high aspect ratio was observed at substrate temperatures above 600 oC. The structural and optical properties of the as grown ZnO NWs were characterized using X-ray diffraction (XRD) and photoluminescence spectroscopy (PL) techniques, respectively. XRD study revealed that, the grown samples possess hexagonal wurtzite structure with (002) preferential orientation. The metal droplets were observed at the tips of ZnO NWs when Au was used as catalyst, but not in the case of Al and Cu. The PL spectra exhibited two peaks, one in the UV region and the other in the visible region. The low-cost Al and Cu metal catalyst assisted growth of metal contamination-free ZnO NWs may be suitable for the device applications.
