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In this work, Gadolinium (Gd3+) substituted Co–Cu–Cr (CCC) SFs with the chemical formula Co 0.5 Cu 0.5 Cr 0.5 Gd x Fe 1.5-x O 4 (x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized via the self-combustion process. The single-phase matrix of the Gd3+ substituted CCC SFs was verified using X-ray diffraction (XRD). The crystallite size (D) of Gd3+ doped CCC SFs was reduced from 51.20 nm to 36.27 nm with increasing Gd3+ doping. The addition of Gd3+ in the CCC SFs lattice enhanced specific surface area (S) from 22.11 cm2/g to 28.57 cm2/g. The energy bandgap (E g) was increased from 4.83 eV to 5.40 eV and revealed an inverse relation with crystallite size. The tangent loss (tan δ), dielectric loss (ε ″), dielectric constant (ε ′), and ac conductivity (σ a c ) of Gd3+ doped CCC SFs exhibit frequency-dependent behaviour. The behaviour of these dielectric properties has been analyzed using both Koop's theory and the Maxwell-Wagner model. Moreover, it was found that the ε ′ was enhanced, while σ a c and tan δ w as reduced with the doping of Gd3+ in CCC SFs. The saturation magnetization and microwave operating frequency were increased with the doping of Gd3+ in CCC SFs. Because of their diverse dielectric and magnetic properties, the Gd3+ doped CCC SFs have considerable potential for different applications, including microwave absorption materials, switching high-frequency devices, and microwave frequency-operating devices. [ABSTRACT FROM AUTHOR]

This study investigates the magnetic response of Ho3+ doped Ni 0.4 Cu 0.6 Ho y Fe 2-y O 4 (y = 0.0, 0.02, 0.04, 0.06, and 0.08) spinel ferrites (SFs) and their correlation with crystallite size. The synthesis was achieved using a sol-gel auto-combustion (SGAC) route and performed different characterizations, including X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray (EDX), Inductively coupled plasma atomic emission spectroscopy (ICP-AES), and vibrating sample magnetometer (VSM) analysis. The cubic spinel phase was verified via XRD in pure NCF and Ho3+ doped NCF samples. The lattice constant (a) was improved from 8.344 Å to 8.378 Å. The substitution of Ho3+ ions led to a decrease in porosity from 42.22 % to 39.54 %. The introduction of Ho3+ ions also reduced the crystallite size (D) from 37.05 nm to 27.72 nm. The specific surface area (S) was increased from 27.44 g/cm2 to 36.14 g/cm2 with the doping of Ho3+. The average particle size (D S) was decreased from 54 nm to 35 nm. The EDX and ICP-AES analyses confirmed the good agreement with the theoretical composition. The VSM measurements provided insights into their magnetic properties. Furthermore, the doping of Ho3+ ions enhanced coercivity (H C), while reducing saturation magnetization (M S) from 64.35 emu/g to 16.22 emu/g. The decrease in crystalline anisotropy (K) observed at higher concentrations of Ho3+ may result from the increase in coercivity, potentially attributable to the smaller crystallite size of the single-domain SFs particles. The single-phase matrix and their magnetic behaviour showed that the Ho3+ doped Ni–Cu SFs samples are suitable for high-frequency applications. [Display omitted] • Ni 0.4 Cu 0.6 Ho y Fe 2-y O 4 was prepared via the sol-gel auto-combustion technique. • The crystallite size was the minimum (27.72 nm) for the y = 0.08 (NCHF4) sample. • The sample has y = 0.08 (NCHF4) and contains maximum coercivity (1031.44 Oe). • The sample has y = 0.08 (NCHF4) and is best-suitable for high-frequency applications. [ABSTRACT FROM AUTHOR]

The sol-gel self-combustion technique was applied to form Cd–Co-based La-doped (Cd 0.5 Co 0.5 La x Fe 2-x O 4) spinel ferrite nanoparticles. A series of six samples was synthesized by varying lanthanum content from x = 0.00 to 0.20. The structural characteristics of the prepared nanoparticles were carried out using X-ray diffraction (XRD) analysis. The (311) plane verified that the prepared nanomaterials are in the spinel phase in all observed XRD patterns. The crystallite size for each sample was determined using the Scherrer formula found in the 8.7–17.8 nm range, which is well correlated with the SSP model. The crystallite size decreased while the lattice constant increased from 8.38 to 8.45 Å with increasing La-content. The increasing trend in the bulk density and X-ray density has been analyzed with the effects of La3+ contents. In Fourier-transform infrared spectroscopy (FTIR), the high-frequency absorption band (υ 1) was found from 522.15 to 541.06 cm−1, whereas the low-frequency band (υ 2) varied from 419.80 to 414.31 cm−1. The surface morphology was carried out by scanning electron microscope (SEM), which positively correlated with XRD analysis. Impedance analyzer (IA) assisted in observing the variations in complex dielectric properties of the compound in the frequency range from 1 MHz to 3 GHz. The dielectric constant and impedance plots depicted that the nano ferrites have good dielectric properties in low-frequency regions due contribution of polarization. While conduction can be made possible in the high-frequency areas as observed through AC conductivity. The electric modulus revealed the relaxation phenomenon at high frequency due to the hopping of electrons at the octa and tetrahedral sites. The magnetic properties were investigated to study the impact of La3+ ion under the applied magnetic field from −15 to 15 kOe. The saturation magnetization, and magnetic remanence were found from 40.6 to 27.7 emu/g and 19.6 to 2.7 emu/g, respectively. The synthesized nanoparticles can be utilized for microwave applications and magnetic storage devices. [ABSTRACT FROM AUTHOR]

a -axis-oriented AlN(100) films are identified as promising candidates for surface acoustic wave devices owing to their high transversal-acoustic velocity. Achieving uniform films across a wafer scale is crucial for enhancing device performance and minimizing manufacturing costs. In this study, we employ radio-frequency magnetron sputtering to deposit AlN(100) films on 2-in Si(100) wafers. We further examine the influence of various process parameters on the nonuniformity of film thickness and structural properties, including crystallite size, microstrain, and dislocation density. The optimization of parameters leads to the selection of a gas flow ratio of N 2 :Ar = 4:7, a sputtering power of 160 W, and a substrate temperature of 350 °C. Under these optimized conditions, the AlN films not only demonstrate a preferred (100) orientation and remarkable crystallinity, as indicated by a full width at half maximum of the X-ray diffraction peak of just 0.03°, but also achieve an optimal film thickness nonuniformity of 1.66 %. Our results offer valuable insights for the wafer-scale fabrication of AlN(100) films, potentially enhancing industrial production yields and reducing costs. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNPs) and spinel ferrites (SFs) composites enhance their properties and enable multifunctional applications, ranging from electronics to environmental and biomedical fields. This study investigates the Ni 0.4 Cd 0.6 Fe 2 O 4 /x-GNPs (x = 0 %, 2.5 %, and 5 %) [ NCF/0%GNPs, NCF/2.5%GNPs, and NCF/5%GNPs ] composites prepared via sol-gel auto combustion (SGAC) synthesis and their enhanced magneto-dielectric characteristics. XRD analysis confirmed the formation of a single-phase spinel matrix of NCF/GNPs composites and observed that the crystallite size (D) was enhanced from 22.8 nm to 33.6 nm with the increasing concentration of GNPs. Moreover, the bandgap energy (E g) was reduced with the incorporation of GNPs in the NCF sample. The dielectric constant and tangent loss were enhanced with the addition of GNPs in the NCF spinel lattice. The saturation magnetization and microwave operating frequency were reduced from 97.42 emu/g to 55.13 emu/g and 21.49 GHz–11.97 GHz, respectively, while the coercivity was observed to increase from 92.66 Oe to 263 Oe with the incorporation of GNPs in the NCF lattice. The study highlights the potential of NCF/GNPs composites for applications in electronics, energy storage, sensors, and biomedical devices. [Display omitted] • Sol-gel auto-combustion synthesis of NCF/GNPs composites. • Single-phase spinel matrix NCF/GNPs composites were observed via XRD. • The bandgap energy was reduced with the incorporation of GNPs. • The magnetic and dielectric properties were enhanced with the addition of GNPs. • The potential of NCF/GNPs composites for applications in electronics, energy storage, sensors, and biomedical devices. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell is promising conversion technology due to fuel flexibility, higher efficiency, and environment friendly compared to traditional technology. To enhance the efficiency of the device, selection of anode material is important because it affects the electrochemical performance and operating temperature of the cell. In this work, La 0.5 Sr 0.5 Al x Cr 1-x O 3-δ (x = 0, 0.1, 0.2, 0.3, 0.4) anode has been developed using sol-gel method. XRD analysis exhibited a two-phase structure of the prepared anode, one orthorhombic and second rhombohedral phase with crystalline size in the range 15–18 nm. The surface morphology of the prepared anode material shows nano-spheres, dumbbells, and platelets. The elemental analysis confirms the presence of Sr, Cr, La, Al, and O in the prepared material. The metal-oxide formation has been confirmed with Fourier Transform Infrared Spectroscopy. The absorption spectra revealed red shift in bandgap 3.65–2.85 eV by increasing the Al concentration. The maximum dc electrical conductivity of the composition anode La 0.5 Sr 0.5 Al 0.4 Cr 0.6 O 3-δ is found to be 8.01 Scm−1 at 600 °C. The achieved power density of the anode La 0.5 Sr 0.5 Al 0.4 Cr 0.6 O 3-δ is 69 mWcm−2 using hydrogen fuel at 600 °C. [ABSTRACT FROM AUTHOR]

The current study aimed to synthesize the bimetallic oxide of TeO 2 –Sb 2 O 4 thin films with different Te weights (0, 10, 20 and 50 wt %.). The chemical vapor deposition (CVD) technique is used for thin film deposition. Various analytical techniques are used for morphological, structural, optical and luminescent characterizations. Results of SEM and XRD indicated that Te contents changed the nucleation and growth rates, hence the regular-irregular morphology. The calculated crystallite size associated with the (222) peak achieved the maximum value of 41.2 nm when Te weight was 10 wt%, in opposite synchronization with both strain and dislocation density. The oxidation kinetics of TeO 2 –Sb 2 O 4 are well explained. The optical analysis by spectrophotometer showed decrease in NIR transmittance (70 - 40%), direct (1.32–1.25 eV) and indirect band gaps (0.96–0.77 eV) with increasing Te weight. The PL spectra showed immutability and increase of the emission peaks of the mixed phase samples. The broad - intense luminescence peak of the bimetallic alloy encouraged their possible applications in light emitting devices. The mixed TeO 2 –Sb 2 O 4 films have longer average life time than the unmixed films which might useable in various applications such as nanothermometers and in time-resolved fluorometry. [ABSTRACT FROM AUTHOR]

Recent developments in nanomaterials have shown that multifunctionality in materials can be best achieved by using doping techniques. In this work, a simple sol-gel approach is employed to successfully prepare Sb-doped SnO 2 nanoparticles. XRD, FESEM, UV–Vis spectra, Pl, and XPS were used to observe the imprints of Sb doping on the structural and optical features of SnO 2 and the photocatalytic capabilities of prepared nanoparticles. The prepared SnO 2 has a tetragonal rutile-type structure, and the crystallite size was found to decrease with an increase in Sb doping from ATO-0 to ATO-4 and then increase with further increment in Sb doping for ATO-6. Band gap energies of 3.5 eV, 3.67 eV, 3.71 eV, and 3.73 eV were observed for ATO-0, ATO-2, ATO-4, and ATO-6, respectively, using UV–Vis spectroscopy. Band gap changes, owing to Sb doping, in the prepared samples, which enhances the absorption in the visible light range. The inherent property of the sample to degrade the methylene orange solution was used to measure the higher photoactive response of the doped sample; this is ascribed to the enhanced efficiency with which photogenerated electron-hole pairs get separated. There is a pronounced effect on the photocatalytic activity of catalysts with antimony doping. Using a Sb–SnO 2 catalyst, the photocatalytic degradation of methylene orange is studied in depth. The improved ability to catalyse a chemical reaction using light has been observed in materials that have been intentionally modified by the introduction of impurities or doping. [ABSTRACT FROM AUTHOR]

This work highlights the synthesis of hollow SnO 2 nanostructures by hydrothermal method and investigation of their morphological features, crystal structure, surface area, elemental composition, and change in resistance to gas as the electrical properties. The synthesis of hollow SnO 2 nanostructures was accomplished by using a modified hydrothermal method starting with a core@shell SiO 2 template, and its nanostructure properties were compared with a SiO 2 @SnO 2 and template-free SnO 2. The STEM analysis revealed that the SnO 2 nanomaterials had a spherical morphology. The crystallite diameters of the hollow and template-free SnO 2 spheres were 3.3, and 4.6 nm, respectively, and their optical bandgap energies were determined to be 4.10, and 3.90 eV, respectively, indicating the influence of quantum confinement effects. The compositions of the SiO 2 @SnO 2 and the hollow SnO 2 nanomaterials were ascertained by XPS studies, which confirmed the purity of SnO 2. By a simple sensing test, the hollow SnO 2 structures were utilized in the sensing of CO at room temperature and the sensor response was found to be six times higher than that of the template-free SnO 2 spheres due to their lower domain size and a large number of active sites. This study indicates that the hollow SnO 2 obtained from a core@shell SiO 2 template has the potential to become a viable sensor material for CO detection at room temperature. [ABSTRACT FROM AUTHOR]

Citrate auto-combustion method was employed to create Bi-perovskite (BFO), Zn-ferrite (ZFO) and Sr-hexaferrites (SFO) nanoparticles, which were then mixed up to form matrix composite which used to separate the lead metal ions from wastewater. Based on XRD peaks, the crystallite size was between 30 and 52 nm. The particles' FTIR spectra clearly show that each synthesized compound has unique functional groups. The samples had agglomeration, with each agglomerate including many grains, as shown by the SEM micrographs. The energy band gap of SFO was enhanced and reduced from 3.5 to 1.5 eV by adding BFO and ZFO. For magnetic study, T C as well as μ eff of BFO and ZFO were improved by adding SFO. While the dielectric properties for pure SFO was enhanced after adding BFO and ZFO in the nanocomposite, in this research paper author succeed in preparing nanosample with upgrading magnetic, optical and electric properties more than individual samples' properties. The synthetic BFO/ZFO/SFO nanocomposite produced impressive results in the treatment of wastewater due to their enormous surface area, regulated size, well-defined structure, and high magnetic, optical and electric properties. Kinetic and isotherm analysis are applied to the experimental results. The high correlation coefficient indicates the adsorption of heavy metal ions, which is described by the Langmuir and Freundlich isotherms (R2). For the 97% removal of Pb (II) from wastewater at a contact duration of 40 min at room temperature and pH 7. [ABSTRACT FROM AUTHOR]

A high surface area is one of desired properties for yttria-zirconia (Y 2 O 3 –ZrO 2) ceramic materials given their catalytic applications. The objective of this study is to develop high-surface-area Y 2 O 3 –ZrO 2 materials by silicon (Si) modification and investigate the role of Si. Si-modified yttrium-zirconium hydroxides were prepared via a one-step precipitation process and calcined at 800 or 950 °C to form Si-modified Y 2 O 3 –ZrO 2 (denoted as SiO 2 –Y 2 O 3 –ZrO 2) materials containing 0-20 wt% Si as SiO 2. These hydroxides or materials were characterized by 29Si NMR, XPS, TG-DSC, XRD, UV Raman, TEM, and N 2 physisorption measurements. Si species uniformly distributed in the hydroxides tended to be enriched on the material surface at high temperatures. These Si species dominated by the silicates blocked the migration of Y and Zr atoms, which resisted the crystallite growth of Y 2 O 3 –ZrO 2 components and reduced their crystallite size. Therefore, the SiO 2 –Y 2 O 3 –ZrO 2 possessed a surface area of 59-112 m2/g after calcination at 950 °C for 9 h, which was significantly higher than that of the Y 2 O 3 –ZrO 2 (23 m2/g). This study may stimulate ideas for developing high-surface-area crystalline ceramic materials calcined at high temperatures. [ABSTRACT FROM AUTHOR]

In this study, Eu3+ doped natural fluorapatites [Ca 10 (PO 4) 6 F 2 :xEu3+ (x = 0.1, 0.3 and 0.5)] were produced from a natural waste by solid-state powder synthesis, conventional sintering, and spark plasma sintering techniques. The effects of doping content and crystallite size on luminescence properties of fluorapatite were investigated by XRD, SEM, and PL analysis. The obtained results showed that luminescence emission's intensity significantly increased with doping content, but no effect was observed on the density and crystallite size. For the samples produced with different methods, emission intensity was the lowest for sintered samples by SPS (1150 °C, 10 min, 50 MPa) with the smallest crystalline size. In contrast, emission intensity was found much higher for synthesized powders with the largest crystallite size. Furthermore, upon excitation under UV radiation, the Eu doped fluorapatites demonstrated the characteristic 5D 0 –7F 2 and 5D 0 –7F 4 emission lines of Eu3+ at 618 nm and 704 nm (red region) with an ultrahigh intensity that has been firstly observed in the literature. Therefore, Eu doped fluorapatites, quickly produced from a natural waste in an eco-friendly and cost-effective way, carry a potential to be used in biological applications and lightning applications. [ABSTRACT FROM AUTHOR]

WC-Ni nanoparticles were synthesized using the gas-solid reaction method in a fixed-bed reactor. The studied parameters were the influence of the synthesis temperatures (800 °C, 850 °C and 900 °C), the reaction time (90 min, 120 min, and 150 min) and the nickel concentration (5 wt%Ni, 10 wt%Ni and 15 wt%Ni) on the average crystallite size by means of a 2³ factorial experimental design based on the results obtained by XRD. These powders had their chemical and morphological characteristics evaluated using XRD, BET, SEM and EDS analyzes. The XRD analysis results show that the method was effective in obtaining WC-Ni nanostructured composite powders with good particle dispersion, desired purity, mean crystallite size ranging from 24.2 nm to 38 nm, and surface area ranging from 24.6 m2/g to 46.7 m2/g. The statistical analysis showed that the synthesis temperature variable had the greatest influence on the increase in crystallite size. Furthermore, the combination of temperature and isotherm also has a relevant effect on the response variable (crystallite size). • Nanostructured composite powders. • Synthesis of WC-Ni nanostructured composite powders by gas-solid reaction method. • Different experimental conditions analyzed by factorial experimental design. • Synthesis temperature has a great influence on the growth of crystallites. [ABSTRACT FROM AUTHOR]

Novel glass-ceramic composites with optical bandgap tunability were synthesised. Zinc silicate powder (ZS) was mixed with multi-walled carbon nanotubes (MWCNTs) at various mass fractions (0, 1, 2, and 3 wt %), followed by argon sintering. X-ray diffraction (XRD) analysis revealed the structural change from an amorphous ZS phase to a crystalline willemite phase (Zn 2 SiO 4) by adding MWCNTs, and the largest crystallite size was obtained for ZS with 2.0 wt% MWCNTs. Although the agglomeration of ZS and MWCNTs was observed by field emission scanning electron microscopy (FESEM), there was no chemical interaction between ZS and MWCNTs as confirmed by Fourier transform infrared spectroscopy (FTIR). MWCNTs enhanced the crystallisation, which led to the green emission of Zn 2 SiO 4 blue-shifting from 572 nm to 557 nm. The narrowed optical bandgap of Zn 2 SiO 4 was attributed to the MWCNT-induced exciton localised between the valence band and conduction band of Zn 2 SiO 4. The bandgap tuning effect of MWCNTs potentially paved new ways to mass fabricate zinc silicate-based semiconductors with desirable optical bandgap energy E g , which significantly benefits the sensor and laser-related industry. [ABSTRACT FROM AUTHOR]

In this study, MgO nanoparticles were successfully fabricated and incubated inside ZnO NPs to form MgO/ZnO nanocomposite for biomedical applications. The x-ray diffraction analysis of MgO, ZnO, and MgO/ZnO has shown the single-phase x-ray diffraction patterns through X'pert High score. The crystallite sizes were calculated as 18 nm, 42 nm, and 53 nm, respectively. The average particle size of MgO, ZnO, and MgO/ZnO nanopowders depicted from secondary electron images of field emission electron microscopy were 56 nm, 400 nm, and 450 nm, respectively. The presence of MgO NPs inside ZnO NPs was confirmed by transmission electron microscopy. The elemental dispersive spectroscopy of MgO, given the peaks of oxygen and magnesium, also showed only zinc and oxygen peaks in ZnO, which confirms no other impurities in MgO and ZnO powders. The elemental analysis of MgO/ZnO nanocomposite showed the peaks of Zinc and Oxygen, along with a tiny peak of Mg. The photoluminescence and UV–vis spectroscopy revealed the absorbance fluorescence limit of the nanomaterials. Fourier transform infrared spectroscopy confirmed the several groups present in the nanocomposite. The biocompatibility of MgO, ZnO, and MgO/ZnO was observed with human peripheral blood mononuclear cells. The cytotoxicity studies were also performed against human cancer (liver and breast) cell lines. The MgO, ZnO, and MgO/ZnO exhibited the antimicrobial properties against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

A novel green synthesis of the combustion pathway was adopted for the preparation of ZnO nanoparticles using Honey and Cow urine. The effects of honey and cow urine on crystalline size, structure, morphology, band gap and thermal properties of ZnO nanoparticles have been analyzed. The polycrystalline hexagonal wurtzite structure of ZnO nanoparticles is confirmed by XRD spectra. The mean crystalline sizes of the ZnO nanoparticles were 23 nm and 29 nm respectively, for the honey and cow urine phase. The external morphology and grain size of the products have been visualized via FE-SEM and TEM. The average sizes of the grains of the ZnO nanoparticles were perfectly associated with the crystalline size measured from the XRD. Spherical and hexagonal shaped nanostructures were reported using FE-SEM and TEM micrographs. The optical absorption spectra of ZnO nanoparticles have been analyzed using UV–Vis spectrometry. In the FT-IR spectra, around 400 cm−1 to 600 cm−1 range have been allotted to the Zn–O vibration. The thermal properties of ZnO nanoparticles have been analyzed using TGA. Changes in weight loss for different ZnO nanoparticles using honey and cow urine have been documented. Gram Positive (B.Subtilis) and Gram-Negative (E.Coli)Bacteria were tested using plate counting technique to study the antimicrobial activity of ZnO nanoparticles prepared by cow's urine and honey. Compared with cow urine-prepared ZnO nanoparticles, honey-assisted ZnO nanoparticles demonstrate strong antibacterial activity. [ABSTRACT FROM AUTHOR]

Crystallite size may significantly impact optical properties of inorganic pigments. However, limited studies have so far been reported in this area. In this work, TiO 2 @NiTiO 3 complex pigments were synthesized by precipitation-calcination method. Results showed that the increase in calcination temperature led to the formation of TiO 2 @NiTiO 3 pigments with crystallite sizes from 29 to 82.6 nm but similar morphologies and aggregate particle sizes (around 1 μm). The yellow component (b*) significantly increased by 7 with crystallite size, but the integrated NIR reflectance decreased slightly (4.02%). Also, the characteristic absorption of NiTiO 3 pigments in NIR region declined the integrated NIR reflectance values. [ABSTRACT FROM AUTHOR]

A straightforward wet chemical method has been applied for the fabrication of Yb 2 O 3 nanoparticles (NPs) from ytterbium nitrate solution by using ammonium carbonate as precipitation agent. Effects of precursor molarity (0.1, 0.15 and 0.2 M), calcination temperature (800, 900 and 1000 °C) and time (2, 4 and 6 h) on average crystallite size (CS) of the NPs were statistically investigated by using Box-Behnken design. A simple and effective quadratic model was proposed for controlling the CS. The CS values were calculated by using Williamson Hall method (W-H) from X-Ray Diffraction (XRD) broadening data and found to be ranging between 13 and 26 nm. Agglomerated NPs morphologies and particle sizes were revealed by Field Emission Gun-Scanning Electron Microscopy (FEG-SEM). Fourier Transform Infrared (FTIR) spectrophotometry confirmed that as-received Yb 2 (CO 3) 3 xH 2 O powders were successfully transformed into Yb 2 O 3 NPs with calcination. High-Resolution Transmission Electron Microscopy (HRTEM) results verified the average CS values. ANOVA analyses revealed that linear and squared terms of the production parameters were significantly related to the CS whereas interaction terms were insignificant with the confidence level of 95% (R2 = 92.67%, R2-adj = 87.17%). The calcination temperature had the highest impact on the average CS followed by the time and precursor molarity. Increasing calcination parameters resulted in bigger crystallites whereas increasing precursor molarity exhibited a critical supersaturation value (0.15 M) from which the average CS was decreased. [ABSTRACT FROM AUTHOR]

The textural properties (specific surface area and pore volume/diameter) of yttria-zirconia (Y 2 O 3 -ZrO 2) ceramic material are critically important to its application in environmental and industrial catalysis. In this work, we tuned the textural properties of the material by a lauric acid-assisted coprecipitation method with high operability and cost-effectiveness. Lauric acid-modified and non-modified yttrium-zirconium hydroxides were prepared. The two hydroxides were then calcined at 700, 800, 900 and 950 °C, respectively, resulting in eight Y 2 O 3 -ZrO 2 oxides. The surface properties and thermal decomposition behavior of the hydroxides and the structural and textural properties of the oxides were systematically investigated. It was found that lauric acid was chemically bound to the hydroxide surface, which decreased the crystallite size of the oxides. More importantly, intercrystalline aggregation in the oxides was significantly inhibited during the thermal treatment. As a result, the textural properties of mesoporous Y 2 O 3 -ZrO 2 solid solution were greatly improved even after the material was calcined at high temperatures. As-prepared materials have higher specific surface area (69 to 24 m2/g) and pore volume (0.24 to 0.18 mL/g) than reported congener materials. This work may stimulate ideas for improved processing techniques which were applied to develop Y 2 O 3 -ZrO 2 ceramic material with excellent textural properties. [ABSTRACT FROM AUTHOR]

An investigation on Rare earth constituent Ce incorporated BiFeO 3 –BaTiO 3 ceramics has been focused in the present study. The ceramic samples of (Bi 0. 7 Ba 0.3) 1-x Ce x (Fe 0. 7 Ti 0.3)O 3 (x = 0–0.12) were formulated adopting the cost-effective solid-state sintering method. The influence of aliovalent Ce ions on the structural, microstructural, dielectric, ferromagnetic, and optical properties of BiFeO 3 –BaTiO 3 was evaluated in this paper. The coexistence of the Tetragonal and the Rhombohedral phases was established by the Rietveld refinement process. The refined crystallographic parameters showed maximum cell volume (V cell) and the highest percentage of the Rhombohedral phase for x = 0.06; and consequently, the ceramic exhibited the topmost dielectric constant of 946 at x = 0.06. The scanning electron microscopy of the samples revealed the manifestation of polygonal grain morphology. Besides, remarkably improved ferromagnetic properties were evinced for Ce doped ceramics. The magnitude of saturation (M s) and remnant (M r) magnetizations were boosted from 0 emu/g and 0.0019 emu/g to 0.9186 emu/g and 0.3745 emu/g respectively with increasing x from 0 to 0.12. Additionally, the optical band gaps of all the samples were evaluated and found to be in the range of 2.941–3.077 eV. [ABSTRACT FROM AUTHOR]

In this research, vapor phase transport (VPT) was introduced as a facile, inexpensive method to produce ZnO micro/nanostructures from various Zn sources such as pure Zn and alpha brass pre-alloyed powders (Cu–20Zn and Cu–28Zn) at different processing temperatures of 930 °C–1050 °C. Simultaneous thermal analysis (STA) was carried out to investigate Zn evaporation and ZnO micro/nanostructure formation. STA results showed an exothermic peck at 711 °C and 728 °C for Cu–20Zn and Cu–28Zn, respectively, due to oxidation of the evaporated Zn element and formation of ZnO micro/nanostructures. X-ray diffraction results showed that high purity ZnO micro/nanostructures were successfully synthesized via VPT process and the crystallite size was increased from ~60 nm to ~100 nm with increasing processing temperature. Field emission scanning electron microscopy observations showed morphology (e.g. rods, column, tetrapods, and combs) and size of the synthesized micro/nanostructures were dependent on the Zn sources and processing temperature, in which average diameter of the synthesized ZnO structures was increased with increasing the processing temperature. The smallest (98 nm) and largest (603 nm) average diameters of synthesized ZnO micro/nanostructures were attained from the pure Zn and Cu–28Zn brass powders at 930 °C and 1050 °C, respectively. [ABSTRACT FROM AUTHOR]

In this study, drug loading and release ability of the ferrite nanoparticle coated with PEG (polyethylene glycol) have been investigated for biomedical applications. The zinc-magnesium ferrite (Zn x Mg (1- x) Fe 2 O 4) was synthesized using sol-gel route. The doping concentration of Zn was gradually increased from zero to maximum (x = 1). XRD (X-ray diffraction) analysis of the samples shows the single phase with a cubic spinel structure. The Debye-Scherer formula has been used to calculate the average crystallite size (30.51 nm). The dumbbell and spherical shaped morphology (40–50 nm average particle size) have been investigated from the secondary electron images of FESEM (Field Emission Scanning Electron Microscopy). The antimicrobial assay has been carried out against E. coli bacteria by gentamicin (drug) loaded ferrite nanoparticles. The significant zone of inhibition might suggest that the drug-loaded ferrite nanoparticles can be used in drug delivery applications. PL (Photoluminescence) of the spinel ferrite shows that all the samples are in the visible range, and peaks at around 430 nm. The result reveals the synthesis of high purity ferrite nanoparticles with significant potential for drug delivery applications. [ABSTRACT FROM AUTHOR]

Herein, we report an efficient, magnetically recoverable and recyclable nanocatalyst to drive a reduction reaction under mild reaction conditions. Nickel ferrite (NiFe 2 O 4) and 20% copper substituted nickel ferrite (Ni 0.8 Cu 0.2 Fe 2 O 4) nanocatalysts were synthesized using a facile glycine-nitrate autocombustion route and employed as catalysts to assess the reduction of 4-nitrophenol in aqueous medium. Phase purity, structural aspects, morphological features and magnetic characteristrics of as-synthesized ferrite powders were carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Elemental compositions of the prepared materials were investigated using EDX analysis. Reduction of 4-nitrophenol to 4-aminophenol using NaBH 4 as the reducing agent with the nanocatalyst was monitered using a UV–Visible spectrophotometry. The results indicate that the Ni 0.8 Cu 0.2 Fe 2 O 4 demonstrated a better catalytic activity with nearly 99% conversion against NiFe 2 O 4 , which showed almost negligible activity over a long period of time. For the first catalytic reduction cycle, time taken by the Ni 0.8 Cu 0.2 Fe 2 O 4 was less than 2 min. However, the reduction time increased progressively as number of cycles increased. Ni 0.8 Cu 0.2 Fe 2 O 4 also displayed a superior catalytic performance over 10 cycles, without a significant drop in its activity. The superior catalytic performance of Ni 0.8 Cu 0.2 Fe 2 O 4 is likely to be due the surface contribution of smaller particles and the presence of Cu2+ at the octahedral site of the spinel ferrite. [ABSTRACT FROM AUTHOR]

The nanoparticles of Ytterbium oxide (Yb 2 O 3) with spherical architectures have been synthesized by using hydrothermal procedure. The prepared Yb 2 O 3 nanoparticles were further doped with Gd3+ ions for exploring the potential of the nanoparticles in terms of tuning the optical properties such as band gap. Here, we demonstrated that the dopant inside the nanoparticles affects the optical properties and show how it has a relevant consequence on the overall peak position of Yb 2 O 3 as a function of dopant concentrations. We have also examined the crystallite changes in Yb 2 O 3 nanoparticles by employing the X-ray peak profile analysis. The respective Williamson–Hall studies and size–strain plot were employed to study the individual roles of crystallite sizes and lattice strain over Yb 2 O 3 nanoparticles as a function of Gd3+ ion doping. The factors including strain, stress and energy density value were computed for both bare and Gd3+ ion doped Yb 2 O 3 nanoparticles. The toxicological profiling of bare and Gd3+ doped Yb 2 O 3 nanoparticles were carried out by multiple assays including antibacterial, antifungal, seed germination assay and A. Cepa genotoxic studies. The results have demonstrated the excellent biocompatibility of prepared nanoparticles and signifying their potential applications in biomedical field. [ABSTRACT FROM AUTHOR]

Mixed phases nanozirconia was synthesized using the sol-gel process in different basic pH. Calcination was performed at 700 °C for 1 and 2 h. The synthesis process and characterization of the nanoparticles were studied by TGA, DTA, FTIR, XRD, FE-SEM and UV–visible. The presence of stable monoclinic and meta-stable tetragonal phases was confirmed by X-ray diffraction patterns for synthesized powders. As pH increased, the amount of tetragonal phase and crystallite size is increased and decreased, respectively. Also, due to the increase of calcination time, the amount of tetragonal phase and crystallite size increased. Micrographs confirmed that the particle shape is semi-spherical after calcination. Moreover, the size of zirconia nanoparticles decreased to 29.8 and 32.9%, as pH increased from 8 to 10 for samples with 1 and 2 h calcination time, respectively. The lowest particle size, 19.3 nm, is related to the sample that was synthesized at pH 10 and calcined at 700 °C for 1 h. UV analysis showed that by increasing the amount of pH, the amount of absorption and the band gap decreased and increased, respectively. [ABSTRACT FROM AUTHOR]

Abstract Multi-ion doping in synthetic HA was carried out using high energy planetary ball milling followed by calcination at 1250 °C for 2 h. The influence of Sr+2, Zn+2, Ag+, and F- ion doping on crystallinity and crystallite size was analyzed using Taguchi design of experiments (DOE) and optimal concentration of different dopants has been identified to achieve desired crystallinity and crystallite size. The doped HA samples have been characterized using X-ray diffraction and Fourier transform infrared spectroscopy to determine their phase purity, degree of crystallinity, crystallite size and functional groups. Standard Analysis of variance (ANOVA) showed relatively high contribution of Sr+2 and Zn+2 doping in changing the crystallinity and crystal size of HA compared to the effect of Ag+ and F- doping. Our analysis demonstrated strong interaction between dopants at binary level doping, while ternary and quaternary doping of elements did not exhibit any interaction in influencing the crystallinity and crystallite size of HA. In general, multi-ion doping in HA found to decrease its crystallinity from 92% to 72% (max.), but enhance the hardness, depending on the type and concentration of doping element. Similarly, a minimum crystallite size of 31 nm was achieved with some binary compositions and other combinations resulted in crystallite sizes up to 59 nm. The compositions that ensure desired crystallinity and crystallite size can also provide high hardness. Our results can be used to tailor the composition of HA in achieving desired functional properties, dependent on crystallinity and crystallite size, such as strength, bioactivity and degradation to suit variety of implant applications. [ABSTRACT FROM AUTHOR]

Abstract This study presents the preparation of pure, Sr and Mg-doped hydroxyapatite (HAP) by precipitation. Sr-doped HAPs (SrHAPs) and Mg-doped HAPs (MgHAPs) were fabricated with Sr molar ratio of 2, 4, 6, 8, 12% and Mg molar ratio of 2, 4%, respectively. Ca(NO 3) 2 , Sr(NO 3) 2 , Mg(NO 3) 2 , (NH 4) 2 HPO 4 were used as starting materials, the Ca/P molar ratio was kept 1.67 during every synthesis and a 900 °C heat treatment was conducted to enhance the crystallinity. All of the products were analyzed by XRD, SEM and EDX, moreover lattice parameters and crystallite size calculations were performed to prove the ion incorporation into the crystal structure. The HAP structure was maintained when 2 and 4 Sr and 2 Mg % were applied and EDX confirmed the Sr and Mg content in these samples. In all other cases, various Sr and Mg-containing phases (Sr 0.13 Ca 2.87 (PO 4) 2 , Ca 2 P 2 O 7 , Mg 0.29 Ca 2.71 (PO 4) 2) were identified while the HAP structure disappeared. It was shown that lattice parameters and the unit cell volume of Sr-doped HAPs increased slightly compared to pure HAP due to the bigger radius of Sr2+ than Ca2+. As the ionic radius of Mg2+ is smaller than Ca2+, we demonstrated the distortion in the unit cell. Crystallite sizes increased as the amount of Sr and Mg raised. SEM experiments demonstrated that ion incorporation had little influence on the morphology, i.e. pure, Sr or Mg-doped HAPs were mostly homogenous, constituted of strongly sintered nanometer sized grains. Antimicrobial tests indicated that SrHAP with 4 Sr % and MgHAP with 2% Mg had positive effect on the inhibition of cell viability. [ABSTRACT FROM AUTHOR]

Abstract Samples containing CuFe 2 O 4 and CuO nanoparticles were synthesized by coprecipitation method and subjected to thermal treatment at 300 °C, 500 °C, 700 °C, 900 °C and 1100 °C. Depending on the synthesis conditions, high-temperature treatment of the prepared samples brought to the formation of CuFe 2 O 4 with a tetragonal or cubic structure, which was confirmed by X-ray diffraction analysis. The influence of formation mechanism onto the crystallite sizes of nanoparticles and structural transformation of CuFe 2 O 4 is discussed. For the first time it was shown that variations of the initial amount of Fe3+and Cu2+ ions precursors resulted in the formation of low- and high-temperature CuFe 2 O 4 phase at the same annealing temperature, 1100 °C. [ABSTRACT FROM AUTHOR]

Nanoparticles of cobalt ferrite (CoFe 2 O 4 ) were synthesized by the EDTA/Citrate complexing method and hydrothermal method without addition of surfactant. The influence of the pH of the reaction medium (8, 9 or 10), the temperature of the thermal treatment (600 °C, 800 °C or 1000 °C for the EDTA/Citrate method, and 120 °C, 140 °C or 160 °C for the hydrothermal method), and the duration of the thermal treatment (2, 4 or 6 h for the EDTA/Citrate complexing method, and 6, 15 or 24 h for the hydrothermal method) on the average crystallite size was studied by means of an experimental design based on the results obtained by XRD. Statistical analysis led to quantification of the influence of the synthesis parameters on the crystallite size of the powders. Results showed that the pH of the reaction medium is the parameter that shows the greatest influence on the growth of the crystallites of the powders obtained by the hydrothermal method, while calcination temperature is the most significant one for the powders produced by the EDTA/Citrate complexing method. [ABSTRACT FROM AUTHOR]

Phase pure SnO 2 powder, containing 0.25 wt% Sb 2 O 3 and 5 wt% Pd was synthesized by sonication assisted simultaneous precipitation method. The as-prepared dry powder and those calcined at various temperatures (200–1000 °C) were characterized by thermal analysis, x-ray diffraction (XRD), transmission electron microscopy (TEM) and surface area (BET) measurements. The effect of calcination temperature on morphology and crystal structure was investigated. The characterization results were employed to rationalize the catalytic sensing behavior towards n-butane gas of nanocrystalline SnO 2 based material incorporated into a thick film device, which detects gas molecules and produces an electrical signal with a magnitude proportional to the concentration of the gas. The powder calcined at 200 °C, having the lowest particle size (~14 nm) exhibited the maximum sensitivity (~96%) at 400 °C operating temperature with very fast response and recovery times suggesting their suitability for development of butane sensors/monitors. [ABSTRACT FROM AUTHOR]

The present study aims at the development of α -Fe 2 O 3 –SiO 2 (hematite–silica) binary oxides for hyperthermia applications. An in situ sol–gel process was attempted to synthesis five different α -Fe 2 O 3 –SiO 2 composites in which the varied concentrations of SiO 2 precursors were added to the constant Fe 2 O 3 precursor. The characterization studies confirmed the formation of α -Fe 2 O 3 phase at 1000 °C. Heat treatments at 1200 °C resulted in the formation of c -SiO 2 along with the presence of α -Fe 2 O 3 phase. The magnetic studies ensured the ferromagnetic behavior of the system, but with a decreasing trend with increasing SiO 2 content. The heating ability of the system was also assessed under an AC magnetic field using an induction heating instrument. The results obtained from hemolytic activity and cytotoxity test warranted the system׳s compatibility in vitro conditions. [ABSTRACT FROM AUTHOR]

Abstract: Nanosized cerium dioxide (CeO2) powders have been synthesized using coprecipitation methods and cerium nitrate hexahydrate (Ce(NO3)3·6H2O) as the starting material. The growth and optical properties of nanosized CeO2 powders were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), nano-beam electron diffraction (NBED), high resolution TEM (HRTEM), and ultraviolet–visible (UV–vis) absorption spectrophotometry. The XRD result shows that the dried CeO2 precursor powders (both before and after calcination at various temperatures and times) contained a single crystalline phase of CeO2. In the dried precursor powders, the crystallites of CeO2 measured 10.4nm and 66.8nm before and after calcination at 1273K for 240min, respectively. The indirect band gap energy ( ) of CeO2 decreased from 3.03eV to 2.68eV as the crystallite size increased from 10.4nm to 66.8nm, whereas the direct band gap energy ( ) of CeO2 also decreased from 3.79eV to 3.38eV. [Copyright &y& Elsevier]

Abstract: Aqueous peroxotitanate complex (PTC) precursor was used to obtain phase pure anatase nanocrystaline TiO2. A wet chemical synthesis route was used in which number of aqueous solutions of PTC was refluxed for different time intervals to study the effect of reflux time on final product. Several characterization techniques were used such as DSC–TGA, XRD, UV–Vis, SEM and TEM. The study revealed that there is a significant influence of reflux time on structural, morphological and optical properties of TiO2. As reflux time of PTC has been increased, crystallite size found to be increased. Also, surface morphology of TiO2 nanoparticles changed from ‘hexagonal shape’ to ‘rice like’ shape and further in ‘ellipsoid rod like’ shape. Optical band gap energy and refractive index incurred to be altered with respect to reflux time of PTC. Detailed study of refluxed PTC solutions has been reported for the first time in the literature. [Copyright &y& Elsevier]

Abstract: The polycrystalline samples of (Pb0.70La0.30)(Al x Ti1−x )O3 (PLAT) (x =0.0, 0.05, 0.10, 0.15, 0.20) were synthesized by conventional solid-state reaction technique and annealed at two different temperatures. A single phase X-ray diffraction pattern was recorded with cubic symmetry of the space group Pm−3m.The Bragg–Brentano geometry is used for indexing, structural solution and Rietveld analysis for our powder samples. The detailed structural study was analyzed by employing Rietveld refinement techniques with the help of the Fullprof Program. The lattice parameters, cell volume, Wyckoff position of the atoms, bond lengths and angles have been calculated from the Rietveld analysis with the help of Powder Cell Program and by taking the refined parameter a stable crystal structure was suggested. It was observed that lattice parameter and cell volume decreases with increase of Al concentration. The crystallite size has been compared by three different methods: Scherrer''s formula, Hall–Williamson method and Rietveld method. The scanning electron microscope (SEM) analysis of the samples shows the uniform microstructure with no abnormal grain growth and the grain size increases with annealing temperature and decreases with the increase of Al concentration. The elemental analysis was confirmed by energy dispersive spectrum analysis. [Copyright &y& Elsevier]

A stoichiometric MgAl2O4 spinel powder was synthesized by a microwave-assisted combustion synthesis (MWCS) route. For the purpose of comparison, another stoichiometric MgAl2O4 spinel powder was also prepared following the conventional combustion synthesis (CCS) method. The batch size had a strong influence on the specific surface area of the material, which in turn is highly dependent on the preparation method adopted. The surface areas of these synthesized powders were found to decrease from 36.78 to 0.1 m2/g for MWCS and 126 to 8.06 m2/g for CCS samples, respectively, when the batch size was increased from 2 to 100 g. This could be attributed to sintering of the samples due to high adiabatic temperature generated as a result of increased heat accumulation with bigger batch quantities. Between the two powders synthesized by the two different routes, the powders obtained by MWCS and CCS routes were found to contain grains/crystals in range of 20–50 and 100–250 nm size, respectively. The thermogravimetry/differential thermal analysis (TG-DTA) and X-ray diffraction (XRD) studies reveal that microwave-assisted combustion synthesis route yields materials with higher degree of compositional stability and phase purity as compared to the conventional combustion synthesis method. [Copyright &y& Elsevier]

Al2O3–ZrO2 powders with 15, 50 and 85 wt.% Al2O3 were prepared by mixing high purity α-alumina powder with Zr(OH)4 gel synthesized by the precipitation method. The obtained mixture was calcined for 2 h at temperatures ranging from 400 to 1300 °C. The effect of the addition of Al2O3 on ZrO2 phase composition in the Al2O3–ZrO2 system was characterized by means of differential thermal analysis, X-ray diffraction and transmission electron microscopy. [Copyright &y& Elsevier]