Peaks In X-ray Diffraction Pattern Research Articles

Influence of plasma synthesis parameters on the magnetic, structural and photocatalytic properties of copper ferrite

CuFe2O4 cubic copper ferrite nanoparticles were synthesized by a new plasma method, the advantage of which is the short duration of processing and cost-effectiveness. To select optimal synthesis conditions, central compositional rotatable experimental planning was used. Using the methods of X-ray phase analysis, vibration magnetometry, electron microscopy, and UV spectroscopy, the sizes of crystallites, the intensity of peaks in X-ray diffraction patterns, dislocation density, saturation magnetization, coercive force, and the degree of degradation of 4-nitrophenol were determined. To study the effect of pH on the composition of the resulting copper ferrites, cyclic voltammetry was used. The kinetics of the ferritization process under the influence of a plasma discharge has also been studied. A mechanism for ferritization in the Cu2+-Fe2+-SO42--OH- system has been proposed.It was found that single-phase nanodispersed powders of cubic copper ferrites with a saturation magnetization Ms 78–93 Emu/g can be obtained by plasma treatment at 300 s and pH 12. Copper ferrite with an admixture of Cu2O is formed at pH = 8.The maximum values of the coercive force correspond to regimes in which the minimum dislocation density is observed. The saturation magnetization depends on the crystallite size. The crystallite size of the resulting powders is in the range of 225–500 A. The results showed that the processing time is the parameter that has the greatest impact on the structural and magnetic characteristics of copper ferrite; the pH of the reaction medium affects them to a lesser extent.

Crystallization of Germanium-SiO2 composite films via nanosecond laser pulse irradiation

Germanium (Ge)-SiO2 composite films fabricated by using radio frequency magnetron co-sputtering were subjected to nanosecond (ns) laser pulse irradiation. The intense laser irradiation effects on as deposited composite films lead to the modification and the formation of Ge nanocrystals (NCs) embedded in SiO2. The as-deposited and laser treated samples have been characterized with X-ray diffraction (XRD) and micro-Raman spectroscopy to understand the formation of Ge NCs due to laser irradiation. The respective Ge NCs related peaks in XRD pattern as well as the Ge-Ge related optical phonon vibrational peaks in micro-Raman spectra confirm the formation of Ge NCs. Transmission electron microscopy images indicate the formation of Ge NCs after the laser irradiation. The effects of laser pulse energy and the irradiation time play a vital role in the crystallization of the as-deposited films. The changes in the Ge NCs size related shifts in the peak position of Ge optical phonons from the Raman spectra of the respective samples are explained with Ge-Ge optical phonon vibrational model. The observed photoluminescence emission in the green and red region of the visible spectrum from the laser treated samples are explained using the phenomenon of creation of Ge NCs in the Ge+SiO2 composite films and the oxygen defects created in SiO2 during the ns laser treatment.

Effects of Processing Strategies and La + Sm Co-Doping on the Thermoelectric Performance of A-Site-Deficient SrTiO3-δ Ceramics

The effect of calcining in either air (VSTO-A) or 5% H2/N2 (VSTO-H) on the thermoelectric performance of La and Sm co-doped A-site-deficient Sr1-3x/2Lax/2Smx/2TiO3-δ ceramics is reported. All calcined powders were sintered 6 h in 5% H2/N2 at 1773 K to ≥96% relative density. All peaks in X-ray diffraction patterns indexed as a cubic perovskite phase. Scanning electron microscopy revealed grain sizes ~14 and ~10 μm for VSTO-A and VSTO-H ceramics, respectively. x = 0.30 showed the lowest k (2.99 W/m.K at 973 K) for VSTO-A, whereas x = 0.20 had the lowest (2.67 W/m.K at 973 K) for the VSTO-H ceramics. x = 0.30 VSTO-A showed a thermoelectric figure of merit, ZT = 0.25 (at 973 K), whereas the maximum ZT = 0.30 (at 973 K) was achieved for x = 0.20 VSTO-H ceramics, demonstrating that thermoelectric properties are optimized when all processing is carried out in 5% H2/N2.

INVESTIGATION OF SILICON-HYDRIDE NANODOTPROPERTIES USING DENSITY FUNCTIONAL THEORY


 
 
 The work aims to elucidate the optical and structural properties of silicon hydride nanoclusters and its bulk via density functional calculations. The molecular geometry is fully optimized with the help of DFT method using Gaussian 09 and Gaussian View 05 Software. Bandgaps are calculated using two approaches; first one using HOMO-LUMO concept and the second one is extracted from UV-vis spectrum. The calculated bandgap of silicon hydride is 3.7 eV. XRD data has also been analyzed using VESTA software, which shows the presence of a silicon matrix that contains organized silicon clusters forming an amorphous silicon matrix. A comprehensive investigation of amorphous films by X-ray diffraction (XRD) shows that the strongest peak in XRD patterns occurs at approximately 30.95°. Using XRD data, average size of optimized silicon hydride nano-cluster has been found to be 158.5 nm. Apparently large value of the cluster size can be attributed to the partially amorphous nature of silicon hydride nanocluster. The partial amorphous nature of silicon hydride is further confirmed from the analysis of its Raman spectrum. An overestimation of size in this case is not ruled out. Raman spectrum is calculated to further confirm deviations in nano-crystalline behavior. We also investigate and reveal properties using IR-spectrum, UV-vis-spectrum, NMR spectrum, and HOMO-LUMO gap.
 
 

Optimal colloidal synthesis and quality judgment of low-dimensional Cs3Cu2Cl5 nanocrystals with efficient green emission

Low-dimensional copper (I)-based ternary metal halides, having the features of nontoxicity, outstanding optical performance and great air-stability, is becoming the promising substitutes for traditional metal perovskite halides. Despite the impressive progress in copper halides, highly effective synthesis of their nanocrystals with precise shape and size control, compared to that of conventional lead halide semiconductors, is still remained to be explored. In this work, we report a systematically optimized finds for the colloidal synthesis conditions of Cs3Cu2Cl5 nanocrystals (NCs). The Cs3Cu2Cl5 NCs are modulated from nanoparticles to nanorods and to nanoplates by adjusting reaction temperature and reaction time. Cs3Cu2Cl5 nanorods give a wide emission at 510 nm, being caused by self-trapped exciton state with exciton binding energy of 137 meV and phonon–electron interaction of 25 meV as determined by temperature-dependent photoluminescence spectra. The photoluminescence quantum yield (PLQY) of the nanorods that were reacted at 150 °C for 1200 s, an optimal reaction condition, reaches up to 80.19%. We also find for the first time that the optical quality of Cs3Cu2Cl5 NCs is positively related to the full width at half maximum of main peak in X-ray diffraction pattern. The findings in this work give a view to the future planning for Cs3Cu2Cl5’s colloidal synthesis and raise an intuitive criterion for the quality of as-synthesized Cs3Cu2Cl5 NCs.

Construction of a New Sensor with Copper(II) Complex Anchored in Calcium Phosphate Intercalated with m-Aminobenzoic Acid and Their Application in Determination of Dopamine

Crystalline lamellar calcium phosphate retained m-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1,033 cm−1 and 1,010 cm−1 intervals confirmed the presence of the phosphate groups attached to the inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 535 pm and 947 pm for the original and the intercalated compounds, respectively. The adsorption isotherm of copper(II) on a calcium phosphate host intercalated with m-aminobenzoic acid was studied in ethanol solution to give a maximum adsorption capacity of 1.43 mmoL g−1. The material was incorporated into carbon paste electrode and its electrochemical properties were investigated. However, for a dopamine solution, an enhancement of the anodic peak current was detected due to the electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for dopamine determination in pharmaceutical preparation (one commercial sample (Revivan)) with success.

Bioproduction of Silver Nanoparticles by Myrtus Communis Leaf Extract and Their Effect on Plant Pathogenic Fungi in Vitro

In this study, Myrtus communis was used for the bioproduction of colloidal silver nanoparticles (AgNPs). The resultant AgNPs were characterized by X-ray diffraction (XRD), UV-Visible spectroscopy and field-emission scanning electron microscopy (FESEM). The hump-like peaks were recorded near the wavenumber 422 nm and such peaks originated due to the electronic structures of silver tiny particles and silver nanoparticles. The four intensive peaks of XRD patterns indicated the crystalline nature and the face-centered cubic structure of the AgNPs. The average crystallite size of the AgNPs ranged from 19[Formula: see text]nm to 25[Formula: see text]nm. The FESEM image illustrates the good dispersion of the AgNPs and the spherical shape of the nanoparticles. The AgNPs were prepared to study antifungal activity against plant pathogenic fungi Aspergillus niger, Rhizopus stolonifer and Neurospora crassain vitro. Results showed that the AgNPs demonstrated high antifungal activity against these fungi with significant differences between treatments when compared with the control (without nanoparticles).

Electrical and Electrochemical Characteristics of Withania somnifera Leaf Extract Incorporation Sodium Alginate Polymer Film for Energy Storage Applications

The current investigation addresses the alternating current electrical properties, electrochemical characteristics on biopolymer as Withania somnifera leaf extract incorporated sodium alginate [WLISA] polymer film prepared by solution casting method. Some crystallinity along with the amorphous nature of sodium alginate emerged due to the incorporation of Withania somnifera leaf extract [WSLE]. Two absorption maximum (λmax) were obtained for both WLISA and WSLE samples in the UV–Vis spectrum. The blue, green, and red emission of WSLE and weak blue emission of WLISA are studied by PL analysis. The more amount of strain that occurred in crystallization provides broaden peak in X-ray diffraction pattern. With aid of guluronic and mannuronic acids in sodium alginate making hydroxyl bond formation with leaf extract due to the cross-linking process can be analyzed from Fourier transform infrared spectroscopy. The EDAX analysis showed the chemical composition of WSLE. At room temperature, the prepared 5 ml leaf extract WLISA film has demonstrated the highest ionic conductivity in the typical value of 2.80 × 10–6 S/Cm. The electrochemical window of the prepared polymer film is in the range of − 0.4 to 0.4 V suggesting that used as an electrolyte for supercapacitor applications.

Structural and in vitro biological evaluation of sol-gel derived multifunctional Ti+4/Sr+2 co-doped bioactive glass with enhanced properties for bone healing

The principal focus of this study was to evaluate the effect of different strontium (Sr) percentages substitution (Sr content = 0, 1, 3, 6, 9, and 12 mol. %) and fixed 5 mol. % titanium (Ti) in bioactive glass (T-BG) in terms of in vitro biological, bactericidal, and structural behaviors of SiO2-60%, CaO-(31-x)%, P2O5-4%, TiO2-5%, SrO-X% (mol. %) TS-BG. The structural analysis of BGs specimens containing Ti and Sr was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectrum (FTIR), Transmittance electron microscopy (TEM), and Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analyses. The alkaline phosphatase (ALP) activity test and 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis were also conducted to investigate in vitro biological behavior of TS-BGs. Meanwhile, the bactericidal efficiency of TS-BGs against MRSA was examined.The SEM results indicated that hydroxyapatite (HA) appeared on TS-BGs' surface after one and two weeks of immersion in the simulated body fluid (SBF). HA characteristic peaks in XRD patterns as well as P–O and C–O bands in FTIR spectra confirmed the in vitro bioactivity. A similar trend in altering MC3T3 cell proliferation and cell differentiation was observed by increasing Sr amount up to 6 mol. %. Then, it had a downward trend up to 12 mol. % Sr. Meanwhile, the more Sr amounts added, the more TS-BGs antibacterial activity was achieved, and the specimen with 12 mol. % Sr and fixed 5 mol. % Ti (TS12) showed 34.27% bactericidal efficiency more than the control specimen (TS0). Taken together, the specimen with 6 mol.% Sr and fixed 5 mol. % Ti (TS6) was chosen as an optimal specimen among the other synthesized TS-BGs because of its higher in vitro bioactivity (HA forming ability after 7 days), MC3T3 cell proliferation, differentiation, and bactericidal efficiency than other specimens.

The Optical Performance of Holmium Oxide Doped Tellurite Glass for Potential Optical Fiber

Borotellurite glass had been widely applied in the field of optical communications and devices. In this work, holmium oxides doped borotellurite glass had been successfully fabricated via conventional melt-quenched technique. The structural properties of holmium doped tellurite glass were found using x-ray diffraction (XRD) method. The nonexistence of sharp peaks in XRD pattern shows that the inclusion of holmium tellurite glass leads to the formation long range of disorderness. The optical properties of the glass system such as refractive index and optical band gap energy are investigated using UV-Vis spectrophotometer. The value of refractive index is found in nonlinear trend along with holmium oxides concentration. It is found that the refractive index is more than 2 at 0.01, 0.03 and 0.04 of holmium concentrations. The optical band gap energy was found in similar trend with refractive index which is in nonlinear pattern.

Study of electrochemical deposition of Ni-Mo thin films from alkaline electrolytes

The process of co-deposition of Ni with Mo from alkaline electrolytes was studied by taking linear and cyclic polarization curves of Pt electrode at various concentrations of initial components and potential scan rates. Solutions of Na2MoO4∙2H2O and NiSO4∙7H2O were used as sources of ions of the main components in NH4OH electrolyte. It was found that co-deposition of nickel with molybdenum goes through the oxide formation stage, and a solid solution of these two metals is deposited on the cathode surface. The film obtained at constant current on Ni electrode under optimal conditions was found amorphous, but additional thermal treatment at 500 °C for one hour made it polycrystalline. This was confirmed by peaks in X-ray diffraction patterns, corresponding to NiMoO4, Ni, and MoO3. The proposed electrolyte and electrolysis conditions allow to obtain thin films with molybdenum content ranging from 17.1 to 50.9 at.%. The co-deposition of Ni with Mo is limited by diffusion of these ions to the cathode surface. The knowledge of the mechanism of co-deposition of Ni and Mo will make possible a selection of optimal conditions for deposition of alloys of the required composition with satisfactory electrocatalytic properties.

Modifications of structural and optical properties of nanophase BaWO4 phosphors: Dose dependent effect of high energy electron beam irradiation

The present work reports dose dependent influence of 8 MeV electron beam irradiation on the structural and optical properties of BaWO4 nanoparticles fabricated by chemical precipitation route. The synthesized materials were calcined at 400 °C for 3 h to get well defined nanocrystalline particles. The calcined materials were irradiated by 8 MeV electron beams of different doses and studied the influence of irradiation on the structural and optical properties of BaWO4 nanoparticles using various characterization tools. The structural studies revealed modifications of lattice parameters a and c, unit cell volume, d spacing, crystallite size, micro-strain, and peak shift for major peaks of X-ray diffraction patterns of the electron irradiated samples. The electron irradiation also results some defects in the crystal lattice of BaWO4 nanocrystals upon electron beam irradiation. Scanning electron microscopic images demonstrated mesoporous behaviour of the BaWO4 materials. The optical studies established that optical bandgap and intensity of photoluminescence emission can be modified by using electron irradiation technique for potential applications in electronics. Photoluminescence emission properties of BaWO4 phosphors suggest that they are useful for the construction of near ultraviolet light excited blue light emitting diodes. Results explored from the present work constitute the first report for the dose-dependent influence of electron beam irradiation on the structure, optical absorption and photoluminescence properties of BaWO4 nanoparticles.

Morphology evolution and quantitative analysis of β-MoO3 and α-MoO3

AbstractThe morphology evolution from monoclinic molybdenum trioxide (β-MoO3) to orthorhombic molybdenum trioxide (α-MoO3) and quantitative analyses of their mixtures were examined. It was found that the morphology (from spherical to elliptical shape) and color (from green to white) displayed obvious changes when β-MoO3converted to α-MoO3in ambient air at 773 K. The transformation from β-MoO3to α-MoO3resulted from a change of the internal crystalline structure. The mass percent of β-MoO3in MoO3mixtures showed an excellent linear relationship with the relative intensity ratio of the strongest peaks in X-ray diffraction patterns. This approach provides a simple and time-saving method to evaluate the amount of β-MoO3, which is a promising material in catalyst and electrochemical applications, in such mixtures. This finding may provide guidance for the analysis of catalytic performance of MoO3mixtures. In addition, it was found that β-MoO3can be easily decomposed into suboxides such as MoO2and Mo4O11in pure argon gas atmosphere. The possible decomposition mechanism of β-MoO3is discussed.

Vertically aligned ZnO nanorods for photoelectrochemical water splitting application

In this present study, nucleation controlled vertically oriented Zinc Oxide nanorod (ZNR) array based Photoanodes was successfully synthesized on conductive substrate by hydrothermal method for Photoelectrochemical (PEC) cell. We have investigated the effect of ammonia during the synthesis on morphology of ZNR and its effect on current–voltage characteristics of PEC cell. Synthesized ZNR were subjected to X-ray diffraction (XRD), UV–Visible spectroscopy, Field emission scanning electron microscopy (FE-SEM), Energy dispersion spectroscopy (EDX) for microstructural characterization. Presence of single (002) peak in XRD pattern confirms vertical c-axis oriented growth of ZnO rods. FE-SEM images revealed that concentration of ammonia had marked effect on crystallization, morphology and density of ZnO rods. PEC properties were investigated by using ZnO rods as photoanode in three electrode cells under AM 1.5G illumination. Morphology and crystallization of ZnO rods had marked effect on current–voltage characteristics.

Preparation of Nanoparticles in an Eco- friendly Method using Thyme Leaf Extracts

Colloidal silver nanoparticles were prepared by single step green synthesis using aqueous extracts of the leaves of thyme as a function of different molar concentration of AgNO3 (1,2,3,4 mM(. The Field Emission Scanning Electron Microscopy (FESEM), UV-Visible and X-ray diffraction (XRD) were used to characterize the resultant AgNPs. The surface Plasmon resonance was observed at wavelength of 444 nm. The four intensive peaks of XRD pattern indicate the crystalline nature and the face centered cubic structure of the AgNPs. The average crystallite size of the AgNPs ranged from 18 to 22 nm. The FESEM image illustrated the well dispersion of the AgNPs and the spherical shape of the nanoparticles with a particle size distribution between 13 to 50 nm.

Investigation of the role of pH on structural and morphological properties of titanium dioxide nanoparticles

In the present research work, titanium dioxide (TiO2) nanoparticles were synthesized by sol-gel method in which titanium tetraisopropoxide (TTIP) used as a precursor and the effect of pH on their structural and morphological properties was investigated systematically. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the prepared samples. The acidity-alkalinity of the gel was adjusted to different pH values (1, 4, 7 and 10) by using respective media, i.e. HCl and NH4OH. The results showed that from strong acidic media to strong basic media, the average particle size was found to increase from 14 nm at pH 1 to 20 nm at pH 10, whereas the average particle size was 19 nm at pH 7. All peaks in XRD patterns perfectly indexed to the stable anatase tetragonal phase except sample at pH 1, where some traces of rutile phase was also present. XRD results showed the formation of single phase high purity nanoparticles. TiO2 nanoparticles showed homogeneous morphology with low agglomeration at pH 7 and pH 10.

Analysis of Organochlorine Pesticides in Drinking Water and their Degradation by Synthesized Iron oxide Nanoparticles

This study reports the analysis of drinking water sources of river Krishni catchment, contaminated by organochlorine pesticides. Iron oxide nanoparticles had been synthesized through co-precipitation method and utilized for the degradation of organochlorine pesticides using advanced oxidation processes. The sharp and narrow peaks of X-ray diffraction patterns revealed the crystalline nature of synthesized iron oxide nanoparticles having size less than 100 nm. The nanoparticles were also characterized using TEM, UV-Vis and IR spectral analysis. Liquid-liquid extraction and GC-MS were used for the detection analysis of pesticides. GC-MS technique was used for further quantitative analysis of 19 pesticides. The degradation analysis showed the maximum amount of degradation (up to 98.38 %) of organochlorine pesticides.

Crystallization and kinetics studies of $$\hbox {Ti}_{{20}}\hbox {Zr}_{{20}}\hbox {Cu}_{60-x}\hbox {Ni}_{{x}}$$ ($$x = 10, 20, 30$$ and 40) metallic glasses

Synthesis and characterization of $$\hbox {Ti}_{{20}}\hbox {Zr}_{{20}}\hbox {Cu}_{60-x}\hbox {Ni}_{{x}}$$ ( $$x = 10, 20, 30$$ and 40) metallic glasses are reported in this paper. Glassy ribbons are produced by rapid quenching using the standard copper wheel roller technique in argon atmosphere. Their structural characterization is carried out by X-ray diffraction (XRD) and thermal behaviour (crystallization) study by differential scanning calorimetry (DSC). Results of XRD on both sides of each ribbon sample confirmed that each sample was indeed amorphous/glassy as only a very broad peak in XRD pattern was observed. Metallic glass $$\hbox {Ti}_{{20}}\hbox {Zr}_{{20}}\hbox {Cu}_{{50}}\hbox {Ni}_{{10}}$$ shows three crystallization peaks in non-isothermal DSC scans while other three samples show only a single crystallization peak. The activation energy of crystallization for each sample has been calculated using three available models, namely, those of Kissinger, Augis–Bennett and Ozawa. All the three models gave nearly similar activation energies for a given sample within 10%.

Production of silver nanoparticles by green synthesis using artichoke (Cynara scolymus L.) aqueous extract and measurement of their electrical conductivity

This work reports the production of silver nanoparticles (AgNPs) by a green method using, for the first time, an extract of artichoke (Cynara scolymus L.), and we explore their electrical properties with the aim of using, for the first time, totally green AgNPs on the preparation of highly conductive inks. The ultraviolet-visible spectroscopy (UV–Vis) studies monitored the surface plasmon resonance phenomenon of green-synthesized silver nanoparticles. Biomolecules of Cynara scolymus L. (CS) extract flower were suggested to be responsible for reducing and capping of AgNPs, by Fourier transformed infrared spectroscopy (FTIR) measurements. Elemental analysis was determined by energy dispersive spectroscopy (EDS). Transmission electron microscopy analysis showed nearly spherical silver nanoparticles surrounded and connected by CS extract material with size varying from 30–80 nm. Scanning electron microscope studies revealed films of AgNPs surrounded by CS extract with nearly spherical and uniformly dispersed silver nanoparticles. The peaks in x-ray diffraction pattern are in good match with that of face-centred-cubic form of metallic silver. The purity and thermal stability of the formed AgNP was detected by differential scanning calorimetry-thermal gravimetric analysis, the melting point at through this analysis was closely related to bulk metallic silver which indicates its purity. Moreover, the electrical resistivity test, the four probe method, confirmed that the green synthesized AgNP using artichoke flower extract had highly electrical conductivity: the resistivity of AgNP films was of c.a. after sintering treatment at for 30 min, which was about three times that of bulk silver . Hence, green synthesis can be a prospective way to develop metallic nanoparticles for the preparation of highly conductive inks with low sintering temperature.

Effects of cathodic polarization on SCC behavior of AA7003 under various aging treatments

In this paper, the effect of cathodic polarization on corrosion behavior of AA7003 under three kinds of aging treatments (including peak aging (PA), double peak aging (DPA) and regression re-aging (RRA)) was studied in 3.5 wt% sodium chloride solution through slow strain rate testing(SSRT) and electrochemical testing. X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods were also applied to investigating corrosion behavior and fracture morphology. The results showed that under open circuit, stress corrosion cracking (SCC) of AA7003 might by classified as anodic dissolution. In this case, the extent of SCC susceptibility (ISCC) of AA7003 alloy with different aging treatments was as follows: ISCC(PA)>ISCC(DPA)>ISCC(RRA). On the other hand, stress corrosion cracking (SCC) of AA7003 under cathodic polarization might be classified as hydrogen embrittlement (HE) which had been proved in this paper by presence of AlH3 diffraction peak in XRD patterns. In this case, for AA7003 with any of the three aging treatments, hydrogen embrittlement susceptibility (IHE) increases with negatively shifting of cathodic polarization.