scholarly journals Effect of CeO2-ZnO Nanocomposite for Photocatalytic and Antibacterial Activities

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 817
Author(s):  
Asad Syed ◽  
Lakshmi Sagar Reddy Yadav ◽  
Ali H. Bahkali ◽  
Abdallah M. Elgorban ◽  
Deshmukh Abdul Hakeem ◽  
...  
Keyword(s):  
Surface Defects ◽  
Uv Light ◽  
Antibacterial Properties ◽  
Combustion Method ◽  
Antibacterial Activities ◽  
Cubic Phase ◽  
Solution Combustion ◽  
Tem Analysis ◽  
Bet Specific Surface Area ◽  
The Impact

The impact of a CeO2-ZnO nanocomposite on the photocatalytic and antibacterial properties compared to bare ZnO was investigated. A CeO2-ZnO nanocomposite was synthesized using Acacia nilotica fruit extract as a novel fuel by a simple solution combustion method. The obtained CeO2-ZnO nanocomposite was confirmed structurally by XRD, FTIR, Raman and UV-DRS and morphologically by SEM/TEM analysis. The XRD pattern indicates the presence of both hexagonal Wurtzite-structured ZnO (major) and cubic-phase CeO2 (minor). FTIR shows the presence of a Ce-O-Ce vibration at 468 cm−1 and Zn-O vibration at 445 cm−1. The existence of a band at 460 cm−1 confirmed the F2g Raman-active mode of the fluorite cubic crystalline structure for CeO2. Diffused reflectance spectroscopy was used to estimate the bandgap (Eg) from Kubelka–Munk (K–M) theory which was found to be 3.4 eV. TEM analysis shows almost spherical-shaped particles, at a size of about 10–15 nm. The CeO2-ZnO nanocomposite shows a good BET specific surface area of 30 m2g−1. The surface defects and porosity of the CeO2-ZnO nanocomposite caused methylene blue (MB) dye to degrade under sunlight (88%) and UV light (92%). The CeO2-ZnO nanocomposite also exhibited considerable antibacterial activity against a pathogenic bacterial strain.

scholarly journals Measurement of the hysteretic thermal properties of W-doped and undoped nanocrystalline powders of VO2

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
C. L. Gomez-Heredia ◽  
J. A. Ramirez-Rincon ◽  
D. Bhardwaj ◽  
P. Rajasekar ◽  
I. J. Tadeo ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Hysteresis Loops ◽  
Thermal Effusivity ◽  
Combustion Method ◽  
Rutile Phase ◽  
Metallic Phase ◽  
Nanocrystalline Powders ◽  
Solution Combustion ◽  
The Impact ◽  
W Doping

Abstract Hysteresis loops exhibited by the thermal properties of undoped and 0.8 at.% W-doped nanocrystalline powders of VO2 synthesized by means of the solution combustion method and compacted in pellets, are experimentally measured by photothermal radiometry. It is shown that: (i) the W doping reduces both the hysteresis loops of VO2 and its transition temperature up to 15 °C. (ii) The thermal diffusivity decreases (increases) until (after) the metallic domains become dominant in the VO2 insulating matrix, such that its variation across the metal-insulation transition is enhanced by 23.5% with W-0.8 at.% doping. By contrast, thermal conductivity (thermal effusivity) increases up to 45% (40%) as the metallic phase emerges in the VO2 structure due to the insulator-to-metal transition, and it enhances up to 11% (25%) in the insulator state when the local rutile phase is induced by the tungsten doping. (iii) The characteristic peak of the VO2 specific heat capacity is observed in both heating and cooling processes, such that the phase transition of the 0.8 at.% W-doped sample requires about 24% less thermal energy than the undoped one. (iv) The impact of the W doping on the four above-mentioned thermal properties of VO2 mainly shows up in its insulator phase, as a result of the distortion of the local lattice induced by the electrons of tungsten. W doping at 0.8 at.% thus enhances the VO2 capability to transport heat but diminishes its thermal switching efficiency.

scholarly journals A Facile Synthesis, Characterization, and Photocatalytic Activity of Magnesium Ferrite Nanoparticles via the Solution Combustion Method

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Loan T. T. Nguyen ◽  
Lan T. H. Nguyen ◽  
Nhuong Chu Manh ◽  
Dung Nguyen Quoc ◽  
Hai Nguyen Quang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Intermediate Phase ◽  
Combustion Method ◽  
Xrd Analysis ◽  
Ferrite Nanoparticles ◽  
Blue Dye ◽  
Magnesium Ferrite ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
Tem Analysis

In this study, we adopted the solution combustion method to synthesize magnesium ferrite (MgFe2O4) using urea as the fuel. Various techniques including TGA, XRD, SEM, TEM, FTIR, UV-Vis DRS, and EDS were employed to characterize the synthesized MgFe2O4 nanoparticles. The XRD analysis revealed that single-phase MgFe2O4 was formed at a calcination temperature of at 500–600°C for 3 hours in the absence of an intermediate phase. TEM analysis also revealed the formation of monodisperse magnesium ferrite nanoparticles, averaged at 30 nm in size. The photocatalytic activity of the synthesized MgFe2O4 nanoparticles against methylene blue dye under visible light was investigated, showing the efficiency of 89.73% after 240 minutes of light irradiation with the presence of H2O2.

scholarly journals Multifunctional Chitosan-Copper Oxide Hybrid Material: Photocatalytic and Antibacterial Activities

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yuvaraj Haldorai ◽  
Jae-Jin Shim
Keyword(s):  
Antibacterial Activity ◽  
Copper Oxide ◽  
Hybrid Material ◽  
Uv Light ◽  
Chemical Precipitation ◽  
Antibacterial Activities ◽  
High Photocatalytic Activity ◽  
Precipitation Method ◽  
Light Illumination ◽  
Tem Analysis

Chitosan (CS) anchored copper oxide (CuO) hybrid material was prepared by chemical precipitation method. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed the formation of CS-CuO hybrid. Transmission electron microscopy (TEM) analysis showed the immobilization of CuO nanoparticles on the surface of CS. The hybrid was also characterized by thermogravimetric analysis (TGA) and zeta potential. The hybrid exhibited high photocatalytic activity as evident from the degradation of methylene blue (MB) dye. The result revealed substantial degradation of the MB dye (84%) under UV-light illumination. The antibacterial activity of hybrid againstEscherichia coliwas examined by colony forming units. It was proved that the CS encapsulated CuO hybrid exhibited excellent antibacterial activity.

Microwave-assisted combustion synthesis of Ni powder using urea

2006 ◽  
Vol 21 (7) ◽  
pp. 1664-1673 ◽  
Author(s):  
Ranjan K. Sahu ◽  
A.K. Ray ◽  
S.K. Das ◽  
A.J. Kailath ◽  
L.C. Pathak
Keyword(s):  
Magnetic Measurement ◽  
Combustion Method ◽  
Exothermic Peak ◽  
Combustion Reaction ◽  
Molar Ratio ◽  
Cubic Phase ◽  
Solution Combustion ◽  
Force Microscopy ◽  
Microwave Assisted ◽  
Ni Powder

A novel microwave-assisted combustion method was used to prepare Ni powder. The method involves the combustion reaction of nickel nitrate and urea as a fuel in the microwave field. The initiation of the exothermic peak of the combustion reaction was found to vary as a function of urea content. The microwave-prepared Ni powder was characterized using x-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, thermogravimetric (TG) analysis, differential thermal analysis (DTA), and magnetic measurement. The XRD pattern revealed that the Ni powder crystallizes with the cubic phase when the molar ratio of fuel to nitrate is varied between 5:1 and 6:1. Above or below that molar ratio, NiO phase coexists as an impurity along with the Ni phase. The magnetization value of Ni measured at room temperature is 53.5 Am2/kg, which is close to the value observed for commercial Ni powder (55.0 Am2/kg). The mechanism for the formation of the Ni and NiO phase is discussed based on the infrared, TG, and DTA data. The method shows that highly pure Ni powder can be prepared using urea as a fuel and microwaves as a source of energy via the solution combustion method.

scholarly journals NiO and Ag@NiO Nanomaterials for Enhanced Photocatalytic and Photoluminescence Studies: Green Synthesis Using Lycopodium Linn.

2019 ◽  
Vol 8 (2) ◽  
pp. 79-85
Author(s):  
K. R. Basavalingaiah
Keyword(s):  
Photocatalytic Activity ◽  
Solution Combustion Synthesis ◽  
Nano Particles ◽  
Blue Dye ◽  
Cubic Phase ◽  
Vibration Band ◽  
Solution Combustion ◽  
Tem Analysis ◽  
Nio Nps ◽  
Photoluminescence Studies

NiO and Ag-NiO nano particles were prepared using Lycopodium extract as a fuel via solution combustion synthesis (SCS) at 500 ºC. From the PXRD, FTIR, UV-DRS studies the synthesized NPs were characterized. The morphologies of the prepared NPs were studied by SEM and TEM analysis. The synthesized NPs were tested for photocatalytic and photoluminescence studies. The PXRD data indicated that the synthesized nanoparticles belong to cubic phase structure and space group Fm-3m. The FTIR spectrum of NiO exhibited the absorption bond at 427 cm-1 is associated to Ni-O vibration band. The SEM data revealed that agglomeration was obtained. NiO and Ag-NiO Nps were taken for determine the photocatalytic activity study on methylene blue dye, the results indicated that Ag-NiO NPs exhibited promising photocatalytic activity. This is due to occurrence of Ag particles on the NiO material, which makes the catalyst more sensitive. Furthermore, a photoluminescence study for NiO and Ag-NiO was studied.

One-step combustion synthesis of undoped c-ZrO2 for Cr(VI) removal from aqueous solutions

2021 ◽  
Author(s):  
Ekaterina Dzhevaga ◽  
Maria Chebanenko ◽  
Kirill Martinson ◽  
Artem Lobinsky ◽  
Vadim Popkov
Keyword(s):  
Heavy Metals ◽  
Aqueous Solutions ◽  
Zirconium Dioxide ◽  
Freundlich Isotherm ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
Point Of Zero Charge ◽  
Cubic Phase ◽  
Maximum Adsorption Capacity ◽  
Solution Combustion

Abstract The active practical application of materials based on cubic zirconium dioxide (c-ZrO2) for catalysis, luminescence, and sorption of heavy metals demands the development of methods for its preparation in a nanostructured form. In this work, nanoparticles of undoped cubic zirconia were obtained by solution combustion method, the features of their structure and morphology were investigated, and the efficiency of their use as a basis for sorbents for the removal of hexavalent chromium Cr(VI) from aqueous solutions was evaluated. Based on XPS, it was established that the stabilization of the high-temperature cubic phase of c-ZrO2 occurred due to multiple oxygen vacancies which were formed during the synthesis by glycine-nitrate combustion. The results of PXRD and Raman spectroscopy confirmed the cubic structure of the obtained zirconium dioxide nanoparticles, the average crystallite size was approximately 2 nm. Adsorption structural analysis and SEM indicated aggregation of c-ZrO2 nanocrystals into primary (45-95 nm) and secondary (submicron) agglomerates. The specific BET surface of the nanocrystals was 25.4 m2/g, the pore volume was 0.1670 cm3/g, the major part of which is associated with interparticle porosity. Using kinetic pH-metry, it was found that on the surface of synthesized c-ZrO2, rapidly hydrated aprotic Lewis acid centers predominated, and the point of zero charge (PZC) was 6.33. The results of Cr(VI) sorption from aqueous solutions with concentrations varying from 0.25 to 1.25 mmol/L were described by the Freundlich isotherm (R2 = 0.971), which corresponds to the multilayer adsorption. The maximum adsorption capacity according to Langmuir was 33 mg/g or 1.34 mg/m2 per unit area. These results allow us to consider the obtained undoped zirconium dioxide as a promising base for sorbents of heavy metals.

Electrochemical Sensing of Dopamine and Antibacterial Properties of ZnO Nanoparticles Synthesized from Solution Combustion Method

2015 ◽  
Vol 14 (03) ◽  
pp. 1550005 ◽  
Author(s):  
K. Manjunath ◽  
K. Lingaraju ◽  
D. Kumar ◽  
H. Nagabhushan ◽  
D. Samrat ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Quantum Confinement Effect ◽  
Antibacterial Properties ◽  
Combustion Method ◽  
Electrochemical Sensing ◽  
Diffusion Method ◽  
Solution Combustion ◽  
Zno Nps ◽  
Solution Combustion Method ◽  
Strong Absorption Band

We have successfully synthesized ZnO nanoparticles (NPs) from solution combustion method using combustible fuel (Green gram). XRD pattern confirms that the prepared compound is composed of wurtzite hexagonal zinc-oxide. FTIR spectrum of ZnO NPs shows the band at ~ 417 cm-1 associated with the characteristic vibration of Zn - O . The UV-Vis spectrum shows a strong absorption band at ~ 365 nm which is blue shifted due to quantum confinement effect. TEM images show the average sizes of the nanoparticles are found to be almost ~ 15–30 nm. The as-synthesized product shows good electrochemical sensing of dopamine. Furthermore the antibacterial properties of ZnO NPs were investigated by their bactericidal activity against four bacterial strains using the agar well diffusion method.

Antibacterial and Photocatalytic Activities of ZnO Nanoparticles: Synthesized Using Water Melon Juice as Fuel

2016 ◽  
Vol 15 (01n02) ◽  
pp. 1650006 ◽  
Author(s):  
L. S. Reddy Yadav ◽  
Danith Kumar ◽  
C. Kavitha ◽  
H. Rajanaika ◽  
B. Daruka Prasad ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Analytical Techniques ◽  
Combustion Method ◽  
Antibacterial Activities ◽  
Zinc Nitrate ◽  
Bacterial Strains ◽  
Solution Combustion ◽  
Zno Nps ◽  
Temperature Solution ◽  
Water Melon

In the present work, Zinc Oxide nanoparticles (ZnO Nps) have been prepared by a simple and low temperature solution combustion method using Zinc nitrate as a precursor and solid water melon juice as a novel fuel for the first time. The structure and morphology of the synthesized ZnO NPs have been analyzed using various analytical techniques such as Powder X-ray diffraction, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy, photoluminescence spectroscopy, scanning electron microscope and transmission electron microscope. ZnO NPs show good photo catalytic activity for the degradation of methylene blue (MB) dye. It also shows significant antibacterial activities against three bacterial strains.

Medicinal Plants: Antibacterial Effects and Chemical Composition of Essential Oil of Foeniculum vulgare

2017 ◽  
Vol 8 (01) ◽  
Author(s):  
Azadeh Foroughi ◽  
Pouya Pournaghi ◽  
Fariba Najafi ◽  
Akram Zangeneh ◽  
Mohammad Mahdi Zangeneh ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Medicinal Plants ◽  
Essential Oil ◽  
Antibacterial Properties ◽  
Screen Test ◽  
Antibacterial Activities ◽  
Gas Chromatography Mass Spectrometry ◽  
Resistant Bacteria ◽  
Antibacterial Effects ◽  
Foeniculum Vulgare

Medicinal plants are considered modern resources for producing agents that could act as alternatives to antibiotics in demeanor of antibiotic-resistant bacteria. The aim of the study was to evaluate the chemical composition and antibacterial activities of essential oil of Foeniculum vulgare (FV) against Pseudomonas aeruginosa and Bacillus subtilis. Gas chromatography mass spectrometry was done to specify chemical composion. As a screen test to detect antibacterial properties of the essential oil, agar disk and agar well diffusion methods were employed. Macrobroth tube test was performed to determinate MIC. The results indicated that the most substance found in FV essential oil was Trans-anethole (47.41 %), also the essential oil of FV with 0.007 g/ml concentration has prevented P. aeruginosa and with 0.002 g/ml concentration has prevented B. subtilis from the growth. Thus, the research represents the antibacterial effects of the medical herb on test P. aeruginosa and B. subtilis. We believe that the article provide support to the antibacterial properties of the essential oil. The results indicate the fact that the essential oil from the plant can be useful as medicinal or preservatives composition.

Direct Plan View FIB Liftout for Near-Surface Defect Analysis in TEM

2013 ◽  
Author(s):  
Max L. Lifson ◽  
Carla M. Chapman ◽  
D. Philip Pokrinchak ◽  
Phyllis J. Campbell ◽  
Greg S. Chrisman ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Silicon Germanium ◽  
Focused Ion Beam ◽  
Surface Defects ◽  
Ion Beam ◽  
Misfit Dislocations ◽  
Tem Analysis ◽  
Plan View ◽  
Near Surface ◽  
Straightforward Method

Abstract Plan view TEM imaging is a powerful technique for failure analysis and semiconductor process characterization. Sample preparation for near-surface defects requires additional care, as the surface of the sample needs to be protected to avoid unintentionally induced damage. This paper demonstrates a straightforward method to create plan view samples in a dual beam focused ion beam (FIB) for TEM studies of near-surface defects, such as misfit dislocations in heteroepitaxial growths. Results show that misfit dislocations are easily imaged in bright-field TEM and STEM for silicon-germanium epitaxial growth. Since FIB tools are ubiquitous in semiconductor failure analysis labs today, the plan view method presented provides a quick to implement, fast, consistent, and straightforward method of generating samples for TEM analysis. While this technique has been optimized for near-surface defects, it can be used with any application requiring plan view TEM analysis.

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