Debye-Scherrer Equation Research Articles

Fabrication and characterization of nanostructured indium tin oxide film and its application as humidity and gas sensors

This paper reports the synthesis and characterization of nanocrystalline indium tin oxide (ITO) and its application as humidity and gas sensors. The structure and crystallite size of the synthesized powder were determined by X-ray diffraction. The minimum crystallite size was found 5 nm by Debye–Scherrer equation and confirmed by transmission electron microscopy image. Optical characterizations of ITO were studied using UV–visible absorption spectroscopy and Fourier transforms infrared spectroscopy. Thermal analysis was carried out by differential scanning calorimetry. Further, the ITO thin film was fabricated using sol–gel spin coating method. The surface morphology of the fabricated film was investigated using scanning electron microscopy images. For the study of humidity sensing, the thin film of ITO was exposed with humidity in a controlled humidity chamber. The variations in resistance of the film with relative humidity were observed. The average sensitivity of the humidity sensor was found 0.70 MΩ/%RH. In addition, we have also investigated the carbon dioxide (CO2) and liquefied petroleum gas sensing behaviour of the fabricated film. Maximum sensitivity of the film was ~17 towards CO2. Its response and recovery times were ~5 and 7 min respectively. Sensor based on CO2 is 97 % reproducible after 3 months of its fabrication. Better sensitivity, small response time and good reproducibility recognized that the fabricated sensor is challenging for the detection of carbon dioxide.

Effect of bismuth ion substitution on structural properties of zinc ferrite nanoparticles

Bismuth doped nano zinc ferrite particles having the general formula ZnFe2-xBixO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by sol-gel combustion method. The effect of bismuth doping on structural properties were investigated. The X-ray diffraction (XRD) spectra confirm the single phase cubic spinel structure. The average crystallite sizes of all the samples were determined by Debye-Scherrer equation and are in the range 16-20 nm. The lattice parameter increases with the increase of bismuth ion concentration. This is due to the larger ionic radius of Bi3+ ions substituting smaller Fe3+ ions at octahedral sites (B-sites). The surface morphology of all compounds was studied by scanning electron microscope (SEM). The microstructure analysis and the particle size were examined by transmission electron microscope (TEM). The compositional stoichiometry of these samples was verified by energy dispersive spectroscopy (EDS) analysis.

Synthesis and Dielectric Properties of Poly Benzyl Bis (Thiosemicarbazone)/Nano Cerium Oxide Nanocomposites

In this study, benzyl bis (thiosemicarbazole) monomer, polymer and poly benzyl bis (thiosemicarbazone) (PBTC) /CeO2 nanocomposites were synthesized through in situ polymerization and their dielectric properties in presence of metal oxide, were investigated. Prepared samples were characterized by Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Structure and morphology of prepared nanocomposites were evaluated by Scanning Electron Microscopy (SEM) and XRD techniques. The dielectric properties were investigated in the frequency range 50 Hz - 20 MHz and the temperature range between 40°C to 150°C. The dielectric constant (e) and dielectric loss (tan δ) is measured for different compositions of nanocomposites. Particle sizes of CeO2 were calculated to be 10 nm from Debye-Scherrer equation. FT-IR verified polymerization of monomers. The dielectric properties of cerium oxide nanocomposite were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanocomposite decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature.

Structural and Magnetic study on Al substituted MgZn mixed ferrite powders prepared by Sol-Gel method

Al substituted mixed ferrites of Zn0.3Mg0.7AlxFe(2-x)O4 (x=0.0, 0.1, 0.2, 0.3, 0.4) prepared by sol-gel auto combustion method. The structural studies using XRD and SEM reveal that the obtained samples were in cubic structure with single phase. As the Al substitution increases in this ferrite system the lattice constant decreases from 8.435A0 to 8.362A0. The average crystallite size calculated using Debye-Scherrer equation and is in the range 26 to 92 nm. The variation in lattice constant and crystallite size attribute due to the replacement of Fe3+ by smaller radii of the Al3+ ion. The magnetic measurements using Vibration Sample Magnetometer (VSM) indicates that the Al3+ preferably occupy B-sites rather than A site. FTIR spectra exhibited two prominent absorption bands in ν1 and ν2, which confirms the redistribution of ions among tetrahedral and octahedral site and spinel nature of these ferrites.

Photocatalytic activity of SnO2 nanoparticles in methylene blue degradation

Nanosized SnO2 photocatalysts were prepared with a precipitation method and were characterized by performing transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). The powder XRD results revealed that the SnO2 nanoparticles have a typical tetragonal rutile (cassiterite) structure and the average crystallite size was found to be approximately 4.5nm by using the Debye–Scherrer equation. The prepared SnO2 nanoparticles consist of agglomerated particles with a mean diameter of around 4–5nm according to the analysis of TEM images. The XAS data confirmed that the prepared samples have cassiterite structures with tin oxidation state of +4. The prepared SnO2 nanoparticles were found to exhibit approximately 3.8 times higher activity than bulk SnO2 in the photodegradation of methylene blue. On the basis of a trapping experiment, we developed a possible mechanism for the photodegradation on SnO2 nanoparticles.

Characterization of CBD-CdSe1-ySy deposited at low-temperature for photovoltaic applications

We present the structural and optical characterization of cadmium selenide sulphur (CdSe1-ySy) deposited by chemical bath deposition (CBD) technique at low-temperature (20 ± 2 °C). The sulphur molar fraction is varied from 0 to 42.13%. The chemical stoichiometry is estimated by energy-dispersive X-ray spectroscopy (EDS). The CdSe1-ySy shows hexagonal wurtzite crystalline phase, which was found by X-ray diffraction (XRD) analysis and it was confirmed by Raman spectroscopy. The average grain size of the CdSe1-ySy films was ranged from 1.20 to 1.68 nm that was determined by Debye-Scherrer equation from W(002) direction and it was confirmed by high resolution transmission electron microscopy (HRTEM). This average grain size indicates a high quantum confinement because of it is smaller than the Bohr radii of CdS (2.8 nm) and CdSe (4.9 nm). Raman spectra show two dominant vibrational bands about 208 and 415 cm−1 associated at CdSe-1LO-like and CdSe-2LO-like. By transmittance measurements at room temperature are found that the optical band gap energies vary from 1.86 to 2.16 eV in the range of investigated sulphur molar fraction. Room temperature photoluminescence shows radiative bands in the visible range and a dominant band in the UV range, approximately 3.0 eV, which can be associated with a radiative transition, bound exciton to donor impurity.

Understanding the combined effects of microcrystal growth and band gap reduction for Fe(1−x)TixF3 nanocomposites as cathode materials for lithium-ion batteries

Whether FeF3 can take active part in electrochemical reaction is largely determined by its conductivity, which can be affected by the band gap and crystallite dimension. In this communication, the density of states (DOS) of FeF3 and Ti-doped FeF3 were calculated using a first principle density functional theory (DFT). Moreover, crystalline size was calculated according to Debye-Scherrer Equation. The results indicate that Ti-doping can reduce the band gap and impact the microcrystal growth of FeF3 at the same time. Both effects work synergistically on capacity loss and cycling stability; while impact antagonistically on charge transfer resistance (Rct), Li+ diffusion coefficient (DLi+) and specific capacity, leading to the excellent electrochemical performances of Fe(1−x)TixF3/C. The Fe0.99Ti0.01F3/C nanocomposite achieves an initial capacity of 219.8mAh/g and retains a discharge capacity of 173.6mAh/g after 30 cycles at room temperature in the voltage range of 2.0–4.5V. The hysteresis of discharge voltage plateau is significantly mitigated as well. In addition, the three-electron reaction of Fe0.99Ti0.01F3/C during 1.0–4.5V exhibits a high initial specific discharge capacity of 764.6mAh/g. This study suggests that not only the band gap, but also the microcrystalline structure can be changed by Ti-doping, both of which have remarkable effects on the electrochemical properties, providing a new perspective on the effect of cation dopant.

Characteristics of Nanosize Spinel Ni<sub>x</sub>Fe<sub>3-x</sub>O<sub>4</sub> Prepared by Sol-Gel Method Using Egg White as Emulsifying Agent

In this study, sol-gel method using egg white as emulsifying agent was applied to prepare nano size spinel NixFe3-xO4 (with x = 0.2–1). Sample preparation was carried out by mixing the solution of Fe(NO3)3.9 H2O and Ni(NO3)3.6 H2O with egg white, and then the sample was stirred thoroughly using magnetic stirrer. After freeze–drying process, the sample was subjected to calcination treatment and subsequently characterized. The phase composition was evaluated using the X-ray diffraction (XRD) technique, followed by quantitative analysis using Rietveld and Debye-Scherrer Methods. The functionality of the sample was identified using Fourier Transform Infrared (FTIR) spectroscopy, and surface morphology and elemental composition were analyzed using scanning electron microscopycoupled with electron dispersive spectroscopy (SEM/EDS). The results of XRD characterization indicated that materials consist of various crystalline phases, with NiFe2O4 as a major phase. FTIR Analysis revealed the existence of both Lewis and Brønsted–Lowry acid sites, with Lewis acid as the prominent site. The sample was found to display relatively homogeneous surface morphology, having the crystallite size in the range of 33 to 61 nm according to the Debye-Scherrer equation. The EDS data indicated that the ratio of Fe/Ni is in agreement with the composition of the raw materials used.

Hydrothermal Synthesis of Fe Based MOFs with Energy Economy Approach

The mesoporous metal organic framework structure Fe-BTC was successfully synthesized by hydrothermal process with noticeable yield. The synthesis operation was conducted at intermediate temperature and for shortened operation time as compared to conventional procedures. This process approach with reduced operating temperature and shortened operation time may open an opportunity window towards process economy with reduction in energy consumption. A simple mathematical approach of diffraction indexing using X-ray diffraction patterns of synthesized powder was employed to confirm its crystalline nature and to investigate its high temperature stability. The crystallite size was calculated by using Debye-Scherrer equation.

Characterization of Copper Oxide Nanoparticles Fabricated by the Sol–Gel Method

Copper oxide nanoparticles were successfully prepared by a sol–gel technique. An aqueous solution of copper nitrate Cu(NO3)2 and acetic acid was used as precursor. On addition of sodium hydroxide (NaOH) a precipitate of copper oxide was immediately formed. The copper oxide nanoparticles were characterized by use of x-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential thermal analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry, and scanning electron microscopy (SEM). The XRD pattern contained sharp peaks of copper oxide nanoparticles with mixed cuprite and tenorite phases. Use of the Debye–Scherer equation showed that the crystallite size of the copper oxide nanoparticles increased with increasing annealing temperature. FTIR spectra revealed vibration of the CuO band at 473 cm−1; a band at 624 cm−1 was attributed to Cu2O. Maximum coercivity and saturation magnetization of the nanoparticles were 276 Oe and 0.034 emu/g, respectively. SEM micrographs of the nanoparticles revealed the presence of spherical nanoparticles of the tenorite phase whereas the cuprite phase was in the form of a compact deposit.

Gd2O3:SiO2 Nanocomposite: Study on Structural and Optical Behavior

Gd(NO3)3·6H2O and TEOS were used as precursors and obtained powdered form of Gd2O3:SiO2 nanocomposite. The as‐prepared sample was annealed at 773 K and 1173 K and characterized by XRD, TEM, UV–Vis spectra, and PL. The average nanocrystallite size was found of the order of ~27 nm using well‐known Debye–Scherer's equation. From the UV–Vis spectra, it was shown that the position of absorption peak has been shifted toward the higher wavelength side with temperature. In the PL spectra, the broad emission band has been observed at 583 nm along with weak bands at 516, 526, and 556 nm.

Preparation of superparamagnetic maghemite (γ-Fe2O3) nanoparticles by wet chemical route and investigation of their magnetic and dielectric properties

Maghemite (γ-Fe2O3) nanoparticles have been synthesized using a wet chemical route, optimizing the reaction time, PH value and size of the crystallite during synthesis. The Powder X-ray diffraction (XRD) measurements confirmed the presence of an impurity free maghemite phase in our sample with an average crystallite size of 16 nm as calculated from the Debye–Scherrer equation. In physical characterization, the room temperature hysteresis (M−H loop) and blocking temperature (as observed from the M-T plot) revealed that the particles are in the superparamagnetic phase at room temperature. Dielectric behaviour of γ-Fe2O3 with respect to the variation of frequency and temperature was also performed. At room temperatures, we observe a decaying behaviour of both dielectric constant (έ) and tangent looses (tanδ) at smaller frequencies while at higher frequencies both saturate to smaller constant values. In temperature dependent dielectric properties we notice that the dielectric constant (both real and imaginary parts) show an increasing trend with increasing temperatures but an overall slower enhancement at elevated frequencies. The former effect can be attributed to the possible delocalization of impurities at higher temperatures while the latter effect can be explained as an inability of the electric dipole moments to respond at higher frequencies.

Applications of chitosan powder with in situ synthesized nano ZnO particles as an antimicrobial agent

ZnO nanoparticles are immobilized on the chitosan matrix by an in situ sol–gel conversion of precursor molecules in a single step. Three different composites are prepared by varying the concentration of sodium hydroxide with same quantity of chitosan and zinc acetate dihydrate. The composites were characterized by FTIR, UV–visible spectra, and XRD. The observed decrease in the band width corresponding to OH and NH2 group in the composites is ascribed to the reduction of hydrogen bond due to the presence of ZnO nanoparticles. The direct evidence of the immobilization of nano ZnO particles in the matrix was identified by SEM. The average particle size values obtained for the nanoparticles, using Debye–Scherrer equation from XRD, is in the range 10–18nm. Optical studies proved that all the three composites studied have the same band gap energy (3.28eV) in agreement with the reported values. We observed that the composites possess excellent antimicrobial activity against Gram negative bacteria Escherichia coli (E. coli) and Gram positive bacteria Staphylococcus aureus (S. aureus) than chitosan. Based on the above studies, the biocompatible, eco-friendly and low-cost composite powder could be applied in various fields as an antimicrobial agent.

Preparation of AlPO4-5 nano-pore crystals: Effect of alteration in precursor gel preparation on the morphology of crystals

Aluminophosphate-5 (AlPO4-5) nano-pore zeolite was synthesized. The effect of alteration in precursor gel preparation on the morphology of zeolite was studied. The effect of variety of synthesis conditions on the purity, crystal and pore size, and crystallinity of AlPO45 zeolite been studied. A hydrothermal synthesis has been used to produce nano-pore Aluminophosphate-5 crystals. The crystals were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The morphology of crystals was changed by alteration on precursor gel. The size of crystals decreased from 10 to 2 micrometer when the aging time of precursor gel was changed from 2 to 12 h. The results also showed that the aluminum triisopropylate, as Aluminum source, has been affected the crystals morepure than the crystals were synthesized by aluminum hydroxide. The Al source was changed affected factors such as the pH precursor gel and then changed the morphology of crystals. The SEM analysis and Debye-Scherrer equation showed that the average particle size is about 58 nm.

Structural, vibrational, electrical and magnetic properties of Bi1−xPrxFeO3

Crystalline solid solution of Bi1−xPrxFeO3 (x=0.05, 0.1, and 0.15) ceramics has been successfully synthesized by a low temperature assisted co-precipitation method. Rietveld-refinement of the X-ray diffraction data reveals rhombohedral structure for Bi1−xPrxFeO3 (x=0.05, 0.10) and triclinic for Bi1−xPrxFeO3 (x=0.15). The crystallite sizes of the Bi1−xPrxFeO3 (x=0.05, 0.1 and 0.15) are found to be approximately 33, 27 and 22nm respectively calculated using Debye–Scherrer equation. The SEM images of Bi1−xPrxFeO3 (x=0.05, 0.10 and 0.15) ceramics show grains with almost spherical morphology. 4A1 and 7E Raman modes have been observed in the range 100–650cm−1 and two phonon modes centered around 1150–1450cm−1 have also been observed corresponding to 2A4 (LO), 2E8 (TO) and 2E9 (TO) modes of Bi1−xPrxFeO3 (x=0.05, 0.1 and 0.15). The changes in Raman modes such as prominent frequency shift, line broadening and intensity have been noticed with the increase of Pr concentration in BiFeO3 (BFO) suggesting a structural transformation as revealed by the Rietveld refinement. An anomaly in the temperature dependent dielectric studies has been noticed in all the samples at the vicinity of Neel temperature (TN) indicating a magnetic ordering and an increase in magnetization with increase of Pr concentration is noticed from the room temperature magnetic studies. Further, the leakage current density is found to be reduced with increasing Pr concentration.

Effect of Tb substitution on structural, optical, electrical and magnetic properties of BiFeO3

Tb substituted BiFeO3 [Bi1−xTbxFeO3 (x = 0.05, 0.10, 0.15)] have been synthesized by a low temperature assisted Co-precipitation method. Rietveld-refinement of the X-ray diffraction data reveals a transition from rhombohedral (R3c) to orthorhombic (Pnma) phase, i.e. polar to non-polar phase with Tb substitution. The crystallite sizes of Bi1−xTbxFeO3 (x = 0.05, 0.1 and 0.15) are found to be approximately 30, 21 and 15 nm calculated using Debye–Scherrer equation. From transmission electron microscopy analysis, the particle sizes are found to be between 35–40, 30–35, and 25–30 nm, respectively for Bi1−xTbxFeO3 (x = 0.05, 0.10 and 0.15) samples. UV–Vis diffuse reflectance spectra show a decrease of band gap with increase in Tb concentration. 4A1 and 7E Raman modes have been observed in the range 100–650 cm−1 and two phonon modes centred around 1150–1450 cm−1 have also been observed. The changes in Raman modes such as prominent frequency shift, line broadening and intensity reveals the existence of substitution induced structural changes as supported by the Rietveld refinement. Temperature dependent dielectric measurements on the samples show magnetoelectric coupling in terms of a dielectric anomaly near the Neel temperature (TN). An enhancement of magnetization with increasing Tb concentration in BFO has been observed from room temperature magnetization studies. The leakage current density is found to be reduced with the increase of Tb concentration. Further, P–E hysteresis loop studies show a decrease of remnant polarization (Pr) with the increase in Tb concentration predicting a transition from ferroelectric (polar) to paraelectric (non-polar) phase as inferred from X-ray diffraction analysis.

Correlation between SnO2 nanocrystals and optical properties of Eu3+ ions in SiO2 matrix: Relation of crystallinity, composition, and photoluminescence

We report characteristics and optical properties of Eu3+-doped SnO2 nanocrystals dispersed in SiO2 matrix. Samples are prepared by the sol–gel method. Crystallinity of SnO2 nanocrystals is examined by X-ray diffraction experiments. At annealing temperatures from 900 to 1200°C, we observe the formation of single tetragonal rutile structure of SnO2 nanocrystals. Average sizes of SnO2 nanocrystals within 3–7nm are estimated by Debye–Scherrer equation. Intense photoluminescent spectra of Eu3+ ions consist of a series of resolved emission bands within 570–645nm, which are varied with different sample-preparation conditions. We show the efficient excitation process of Eu3+ ions through SnO2 nanocrystals in the materials. Microscopic structure of SnO2 nanoparticles and optical properties of Eu3+ ions are also presented and discussed.

Green Synthesis and Characterization of Silver Nanoparticles Using Ferocactus echidne Extract as a Reducing Agent

The green synthesis of silver nanoparticles using an aqueous extract of Ferocactus echidne(a member of the cactus family) as a reducing agent is reported. It is simple, efficient, rapid, and ecologically friendly compared to chemical-mediated methods. Ferocactus echidne is a plant of high medicinal value and rich in polyphenolic antioxidants. The extraction is simple and the product rapidly reduces silver ions without involvement of any external chemical agent. The reduction of silver nanoparticles was characterized by ultraviolet-visible spectrometry as a function of time and concentration. The results show that Ferocactus echidne reduces silver ions within 6 h depending upon the concentration. Further increases in reaction time may result in a blue shift, indicating an increase in particle size, whereas concentration had a minor effect on the particle size. The structure of synthesized nanoparticles was investigated by infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The infrared spectra indicated the association of organic materials with silver nanoparticles to serve as capping agents. Scanning electron micrographs showed that synthesized silver nanoparticles were nearly uniform and elliptical in shape with diameters of 20 to 60 nm. X-ray diffraction confirmed the formation of silver nanoparticles with an approximate 20 nm particle size calculated using the Debye-Scherer equation. Biological tests revealed that the silver nanoparticles were active against gram positive and negative bacteria( Escherichia coli and Staphylococcus aureus) and fungi (Candida albicans), indicating their broad spectrum antibiotic and antifungal abilities.

Electrochemical synthesis, characterisation and phytogenic properties of silver nanoparticles

This work exemplifies a simple and rapid method for the synthesis of silver nanodendrite with a novel electrochemical technique. The antibacterial activity of these silver nanoparticles (Ag NPs) against pathogenic bacteria was investigated along with the routine study of optical and spectral characterisation. The optical properties of the silver nanoparticles were characterised by diffuse reflectance spectroscopy. The optical band gap energy of the electrodeposited Ag NPs was determined from the diffuse reflectance using Kubelka–Munk formula. X-ray diffraction (XRD) studies were carried out to determine the crystalline nature of the silver nanoparticles which confirmed the formation of silver nanocrystals. The XRD pattern revealed that the electrodeposited Ag NPs were in the cubic geometry with dendrite preponderance. The average particle size and the peak broadening were deliberated using Debye–Scherrer equation and lattice strain due to the peak broadening was studied using Williamson–Hall method. Surface morphology of the Ag NPs was characterised by high-resolution scanning electron microscope and the results showed the high degree of aggregation in the particles. The antibacterial activity of the Ag NPs was evaluated and showed unprecedented level antibacterial activity against multidrug resistant strains such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia and Escherichia coli in combination with Streptomycin.

Biosynthesis of silver nanoparticles from Premna serratifolia L. leaf and its anticancer activity in CCl4-induced hepato-cancerous Swiss albino mice

In this study, we report the biosynthesis of silver nanoparticles using the ethanolic leaf powder extract of Premna serratifolia L. and its anticancer activity in carbon tetra chloride (CCl4)-induced liver cancer in Swiss albino mice (Balb/c). The synthesized silver nanoparticles were characterized by SEM, FTIR and XRD analyses. The Debye–Scherrer equation was used to calculate particle size and the average size of silver nanoparticles synthesized from P. serratifolia leaf extract was 22.97 nm. The typical pattern revealed that the sample contained cubic structure of silver nanoparticles. FTIR analysis confirmed that the bioreduction of silver ions to silver nanoparticles is due to reduction by capping material of the plant extract. The silver nanoparticles of P. serratifolia leaf extract were effective in treating liver cancer in Swiss albino mice when compared with P. serratifolia leaf extract with isoleucine.