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In this study YAG (Y3Al5O12) nanopowders have been synthetized by a reverse co-precipitation method with two different designs of reactors: batch and plug-flow. The impact of both the reactor design and the synthesis temperature on the features of nanopowders so-synthetized was studied. The reactor design governs the pH evolution and precipitation kinetics during synthesis. Correlations were found between the reactor design and nanopowders stoichiometry and morphology. The plug-flow reactor allows obtaining homogeneous, well-crystallized and single-phased YAG nanopowders after calcination. Then, the sintering ability of as-obtained nanopowders was investigated. Fully dense YAG-based ceramics were obtained with the nanopowders made from the plug-flow reactor by combining uniaxial pressing and sintering at 1700 °C. Finally, a plug-flow reactor with very simple and inexpensive design would allow easier upscale of the synthesis process of YAG-based nanopowders with well-controlled morphology and stoichiometry. As a result, YAG based transparent ceramic were obtained without sintering additive.

Composite electrolytes of sodium carbonate and samarium doped ceria (SDC-Na 2 CO 3) provide outstanding proton conductivity between 300 °C and 650 °C, which is extremely sensitive to the synthesis procedure and to the amount and crystallinity of the carbonate phase. Here, the role of sodium carbonate in establishing the composite conductivity is explored in relation to chemical-structural and morphological characterization methods (ICP, XRD, SEM, TEM). A coprecipitation route is properly optimized to prepare composites with <50 nm SDC particles with sodium carbonate in different amounts. The amount of carbonate, carefully quantified via elemental analysis, strongly influences the proton conductivity, while the oxygen ion conductivity is much less affected. The formulation with 27 wt% of carbonate prepared through a single-step synthesis shows the best performance, with 2.27*10−2 S cm−1 proton conductivity in dry hydrogen (4 % H 2 in N 2) at 600 °C, and 1.73*10−2 S cm−1 oxygen ion conductivity in air. Interestingly, an SDC-Na 2 CO 3 composite containing the same salt amount but produced via a double-step procedure showed lower conductivity, confirming the pivotal role of the preparation methodology in defining the composite proton conductivity. In addition, humidification is found to depress H+ conductivity, thus indicating that the preferential charge transport mechanism does not involve hydroxides, in contrast to conventional protonic ceramics. Overall, the investigation reveals a strong dependence of the composite proton conductivity on the density of the carbonate/SDC interfaces and the crystallinity of the carbonate. [Display omitted] • Nanocomposites of Na 2 CO 3 and Sm 0.2 Ce 0.8 O 1.9 (SDC) are synthesized by coprecipitation. • SDC nanoparticles with Na 2 CO 3 shell are obtained with a consistent synthesis protocol. • 27 % wt Na 2 CO 3 leads to optimal proton conductivity between 400 °C and 650 °C. • 1.68 10−2 S/cm H+ conductivity and 1.73 10−3 S/cm O2− conductivity are found at 600 °C. • Dry H 2 feed boosts proton conductivity, while humidification reveals detrimental. [ABSTRACT FROM AUTHOR]

Magnesium silicates combining acidic and basic surface properties are known to be interesting as heterogeneous catalysts. Nevertheless, their catalytic performances are highly dependent on the synthesis method used. In this study, a series of magnesium silicates was synthesized for the first time using a coprecipitation method with a micromixer. It is first shown that changes in synthesis/precipitation pH led to magnesium silicates with different Mg/Si ratios: the higher the synthesis pH, the higher the Mg/Si ratio. Moreover, prepared silicates with a final Mg/Si ratio greater than 0.7, thus prepared at high pH, exhibit negligible specific surface area, whereas relatively high values (>180 m2/g) have been obtained for lower Mg/Si ratios. A set of experimental characterization data obtained by N2 physisorption, SEM, XRD, TGA-DTA as well as Raman and 29Si NMR spectroscopies are presented and discussed. They show the existence of two distinct families with a similar Magnesium Silicate Hydrate (MSH) phase, but they reveal different aggregation states and textural properties. Finally, the surface acid–base reactivity of the co-precipitated magnesium silicates was determined using the model reaction of 2-methylbut-3-yn-2-ol (MBOH) conversion. The results obtained suggest that it is possible to prepare silicates with a wide range of surface acid–base properties, from purely basic solids to those with both acidic and basic properties, by adjusting the final Mg/Si ratio via the control of the synthesis parameters. [ABSTRACT FROM AUTHOR]

BaFe12O19 (BaM) hexagonal ferrite was synthesised through the co-precipitation route. The thermal decomposition behaviour of co-precipitated powder was studied by DSC-TG. XRD and Raman analysis confirmed the formation of pure BaM phase at 900°C calcination temperature. Morphological analysis was done using FESEM. The magnetic behaviour of BaM was analysed using a vibrating sample magnetometer. The saturation magnetisation (Ms) of 67.7 emu g−1 and coercivity of 5106 Oe was observed in BaM. BaM ferrite with a surface area of 8.2 m2 g−1 was used for the adsorption of methyl blue (MB) and sunlight-induced photodegradation. The optical band gap of the ferrite was ~2.9 eV. The adsorption process followed the pseudo-second-order model and satisfied Langmuir adsorption isotherm. BaM particles showed the maximum Langmuir saturation adsorption ability of 223.86 mg g−1 at an initial MB solution pH of 5.7. The free energy and enthalpy changes of the adsorption confirmed the spontaneous and exothermic nature of the process. About 73% of degradation of MB was found within 3 h of sunlight-induced photocatalytic degradation. Reproduced BaM powder showed high adsorption and degradation efficiency even after five cycles. All these results suggest that BaM particles can be used as a promising material for the adsorption and degradation of MB in wastewater treatment. [ABSTRACT FROM AUTHOR]

β‐tricalcium phosphate (β‐TCP, β‐Ca3(PO4)2) is an attractive biomaterial for bone repair applications. However, its sintering and mechanical properties are limited by a problematic phase transition to α‐TCP. Cationic doping of β‐TCP is able to postpone the formation of α‐TCP allowing higher sintering temperatures and better mechanical properties. The co‐doping of β‐TCP with Mg2+ and Sr2+ has already been studied in detail, but the addition of antibacterial cations (Ag+ and Cu2+) on the Mg–Sr β‐TCP co‐doped composition remains unexplored. Thus, two co‐doped β‐TCP compositions were realized by aqueous precipitation technique without any secondary phase and compared with undoped β‐TCP: Mg–Sr (2.0–2.0 mol%) and Mg–Sr–Ag–Cu (2.0–2.0–0.1–0.1 mol%). Differential thermal analysis and dilatometry analyses showed a slight decrease of the β‐TCP → α‐TCP phase transition temperature for the Mg–Sr–Ag–Cu (2.0–2.0–0.1–0.1% mol) composition as compared to the Mg–Sr (2.0–2.0 mol%). However, both exhibited much higher transition temperatures than undoped β‐TCP. The addition of Ag+ and Cu2+ slightly reduces the grain size after sintering compared to the Mg–Sr (2.0–2.0 mol%) and the undoped compositions. The co‐doped compositions also exhibited improved mechanical properties, specifically a higher Vickers hardness and elastic modulus. Finally, cell proliferation assays showed that the presence of dopants, even Ag+ and Cu2+, does not affect the survival and proliferation of cells. Thus, the use of Mg2+, Sr2+, Ag+, and Cu2+ co‐doped β‐TCP could be very promising for biomedical applications due to the improvements of these dopants on the thermal stability and mechanical and biological properties. [ABSTRACT FROM AUTHOR]

Magnesium silicates combining acidic and basic surface properties are known to be interesting as heterogeneous catalysts. Nevertheless, their catalytic performances are highly dependent on the synthesis method used. In this study, a series of magnesium silicates was synthesized for the first time using a coprecipitation method with a micromixer. It is first shown that changes in synthesis/precipitation pH led to magnesium silicates with different Mg/Si ratios: the higher the synthesis pH, the higher the Mg/Si ratio. Moreover, prepared silicates with a final Mg/Si ratio greater than 0.7, thus prepared at high pH, exhibit negligible specific surface area, whereas relatively high values (>180 m2/g) have been obtained for lower Mg/Si ratios. A set of experimental characterization data obtained by N2 physisorption, SEM, XRD, TGA-DTA as well as Raman and 29Si NMR spectroscopies are presented and discussed. They show the existence of two distinct families with a similar Magnesium Silicate Hydrate (MSH) phase, but they reveal different aggregation states and textural properties. Finally, the surface acid–base reactivity of the co-precipitated magnesium silicates was determined using the model reaction of 2-methylbut-3-yn-2-ol (MBOH) conversion. The results obtained suggest that it is possible to prepare silicates with a wide range of surface acid–base properties, from purely basic solids to those with both acidic and basic properties, by adjusting the final Mg/Si ratio via the control of the synthesis parameters.

NaMgF3‐based phosphors have been described frequently in the literature. Their synthesis faces difficulties typical of fluoride materials. A simple precipitation synthesis for NaMgF3‐based phosphors is described in this paper. This consisted of mixing aq. NaF and MgCl2/MgSO4 solutions. Various activators could be incorporated by adding the required salts during this process. Characteristic emission of the activators was observed in the prepared phosphors. As‐prepared samples exhibited predominantly trivalent lanthanide emission. After thermal treatment in a reductive atmosphere, europium‐doped samples showed the intense emission of Eu2+. By virtue of the intense nature of the emission, lifetime measurements could be made for this sample. Notably, intense thermoluminescence and optically stimulated luminescence were observed in NaMgF3:Eu. A simple, fast method for the synthesis of NaMgF3 was therefore developed. [ABSTRACT FROM AUTHOR]

The morphology dependent optical properties of Tb3+ in YbPO4 host lattice have been investigated. 10 % Terbium doped ytterbium phosphate (YbPO4:Tb3+) nanostructures (NSs) were synthesized by five different synthetic methods i.e. sonochemical method, hydrothermal method, solvothermal method, sacrificial template method and coprecipitation method. Structural facets and optical properties of fabricated nanoparticles were studied in detail by powder X-ray diffraction (PXRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectra (EDS), and photoluminescence (PL) techniques. We have investigated the impact of synthetic procedures employed on the morphology and uniformity of synthesized NSs and consequently on the optical properties of the NSs. The intense green emission from the nanophosphor shows that phosphor can be used in IR-sensors, LEDs and as solar spectrum converters.

In this work, β-tricalcium phosphate (β-TCP) is doped with Mg2+ and Sr2+ in order to postpone the problematic β-TCP → α-TCP transition occurring from 1125 °C. Indeed, this phase transition occurs with a large lattice expansion during sintering causing microcracks and a reduced shrinkage leading to poor mechanical properties of ceramic parts. The substitution of calcium by cations like Mg2+ and Sr2+ allows to increase the temperature corresponding to β→α-TCP transition and therefore to increase the sintering temperature and achieve higher densification level. Three doping rates for each dopant individually (2.25, 4.50 and 9.00 mol%) and two co-doped compositions (2.00 mol% and 4.00 mol% of Mg2+ and Sr2+ simultaneously) were tested. Thermal and dilatometric analyses were used to evaluate the effects of Mg2+ and Sr2+ doping on the thermal stability of β-TCP. It has been shown that all doping, except the 2.25 mol% Sr-TCP, postpone the β→α transition. These results were confirmed after conventional and microwave sintering. Indeed, X-ray diffraction analyses of sintered pellets showed that the only phase present is β-TCP up to 1300 °C in all compositions except for the 2.25 mol% Sr-TCP with both sintering ways. Moreover, a higher densification rate is observed with the presence of dopants compared to undoped β-TCP according to the microstructures and relative densities close to 100%. Finally, the duration of microwave sintering is almost sixteen times shorter compared to conventional sintering allowing rapid densification with similar final relative densities and microstructures with finer grains.

A novel method for bottom-up synthesis of two-dimensional (2D) gadolinium-doped cerium oxide (CGO) nanosheets is developed and demonstrated as an efficient precursor for interdiffusion barrier layer deposition in solid oxide fuel cells. The CGO is the standard material used as an interlayer in intermediate-temperature solid oxide fuel cells to avoid undesirable reactions between lanthanum strontium cobalt ferrite (LSCF) cathode and yttria-stabilized zirconia (YSZ) electrolyte materials. Herein, the shape-control of the 2D CGO by a low-cost wet-chemical method allowing for the fabrication of fully dense barrier layer of CGO is reported. The high surface coverage promoted by the 2D CGO nanosheets resulted in a thin (∼ 1 µm) and dense interdiffusion barrier layer sintered at 1150 °C preventing the undesirable reaction between oxide ion conducting phases occurring at higher temperatures. The electrochemical properties of solid oxide fuel cells confirmed the CGO nanosheet as an efficient layer for preventing the formation of resistive phases at the electrolyte/cathode interface. [Display omitted] • Innovative synthesis method for efficient 2D-layered gadolinium doped-ceria (CGO) electrolytes. • 2D CGO nanosheets, with high surface coverage, result in dense layer at mild sintering temperature. • CGO nanosheets prevent resistive phases and enhance solid oxide fuel cell performance. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we have prepared Co‐doped ZnO nanocomposites by zinc nitrate and cobalt sulfate as new precursors via the coprecipitation method and the samples were followed to identify the morphological, optical, structural, and magnetic properties. The XRD patterns revealed the crystalline nature of nanoparticles with hexagonal wurtzite structures, which meant that Co impurity did not disturb the structure of pure ZnO and the minimum crystallite size of nanoparticles was calculated to be around 37 nm. The XRD patterns also showed the lattice parameter increase owing to the incorporation of a Co dopant. The TEM results revealed the sphere‐like particles whose size varied between 56 and 88 nm in diameter at a 4% level of impurity. DRS analysis identified that the band gap energy decreased from 3.18 eV for the pure substance to 2.36 eV for the 10% impure substance. VSM analysis exhibited that the saturation magnetization value increased to 8.4 × 10−3 emu/g for the highest Co content of 10%, which indicated the ferromagnetic behavior of NPs. [ABSTRACT FROM AUTHOR]

Considerable efforts have been focused on the exploitation of macromolecule ligands for synthesis of magnetic Fe3O4 nanoparticles as T1 magnetic resonance imaging (MRI) contrast agents, but studies that concern macromolecule ligands with different charges and coordination groups are still limited. Herein, we used poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and polyvinyl alcohol (PVA), which possess negative, positive and neutral charges with carboxylic acid, amino and hydroxyl groups respectively, as templates and stabilizers to fabricate Fe3O4 nanoparticles through coprecipitation reaction. The obtained Fe3O4-PAA, Fe3O4-PAH, and Fe3O4-PVA nanoparticles showed T1 contrast performance with r1 relaxivities of 23.4, 60.3, and 30.6 mM s−1 at 0.5 T (25 °C), and a r2/r1 ratio of 2.62, 3.82, and 7.26, respectively. The cell viability assay revealed that Fe3O4-PAA and Fe3O4-PVA exhibited good biocompatibility, while Fe3O4-PAH displayed high cytotoxicity. In vivo T1-weighted (1 T) mice showed that both Fe3O4-PAA and Fe3O4-PVA were able to display remarkably brighten the contrast enhancement for the mice tumor and kidney sites, but Fe3O4-PAA had better contrast performance. This work highlights that the macromolecule ligands play an important role in the biocompatibility and T1 contrast performance of magnetic Fe3O4 nanoparticles.

A series of GdYbErGePO germanate phosphates differing in the ratio of the Yb and Er active ions have been synthesized, and their luminescence spectra have been measured. According to X-ray diffraction characterization results, all of the synthesized germanate phosphates are single-phase and have a triclinic structure (sp. gr. P1). We have measured upconversion luminescence spectra due to the Er H, S → I and F → I radiative transitions in the synthesized gadolinium ytterbium erbium germanate phosphates and determined the luminescence upconversion energy yield ( B ) in GdYbErGePO. The effects of the concentrations and ratio of the dopants in the Gd(GeO)(PO)O germanate phosphate host on B and the ratio of the luminescence intensities in the red and green spectral regions ( R/G) have been assessed. [ABSTRACT FROM AUTHOR]

The influence of A-site cation doping, crystal structure and structural defects (oxygen nonstoichiometry) on the electrical conductivity of Sr-doped CaMnO 3 (CSMO) and BaMnO 3 (BSMO) was investigated. CSMO and BSMO were prepared by citrate-nitrate autocombustion and coprecipitation synthesis, pressed into pellets and sintered. Since the oxygen nonstoichiometry in CSMO was uniform, the increase in electrical conductivity was primarily caused by the increase in Sr content. On the other hand, the oxygen nonstoichiometry in BSMO was more pronounced and it decreased with Sr-doping. Therefore, the highest conductivities were obtained for the undoped BaMnO 3 samples. The electrical conductivities of CSMO were similar to those of widely investigated rare-earth manganites and more than 104 times higher than those of BSMO. Therefore, CSMO has the potential to be a low-cost cathode material in solid oxide fuel cells. • Both autocombustion and coprecipitation are suitable for CSMO and BSMO preparation. • Autocombustion synthesis yielded materials of higher electrical conductivity. • CSMO possess electron conductivity comparable to the LSMO. • BSMO crystal structure is without distortions, resulting in low conductivity. • Oxygen vacancies have the main role in the conductivity of BSMO. [ABSTRACT FROM AUTHOR]

The series of nanocrystalline (≈5–10 nm), lanthanide doped fluorides – CeF 3 :Gd 3+ , Sm 3+ were prepared by a simple coprecipitation method. The as-prepared nanoparticles were hydrothermally treated, which resulted in increased crystallinity and size of the nanocrystals formed (≈50–100 nm). The precipitated products (before the hydrothermal treatment) exhibited pink luminescence. The hydrothermal post-treatment of the colloidal nanomaterials caused alteration of their luminescence, namely the emission was tuned from pink to orange. This was because of the increased energy transfer from Ce 3+ and Gd 3+ ions to the Sm 3+ ion (luminescence activator), in larger and better crystallized nanoparticles. The products obtained in the presence of EDTA and citric acid revealed altered morphology, being more homogeneous and monodisperse, as well. The structural and morphological properties of the nanomaterials synthesized were determined by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and infrared spectroscopy (FT-IR). Elemental analysis, thermogravimetric–differential thermal analysis (TG–DTA) and energy dispersive X-ray analysis (EDX) confirmed the nanomaterials composition. The luminescence properties of the products were studied based on the recorded excitation/emission spectra and emission–decay curves. Radiative lifetimes and luminescence quantum yields were also determined. [ABSTRACT FROM AUTHOR]

KMgF 3 is an important optical material. It is usually synthesized by conventional, high temperature solid state reaction or by melting the constituents together followed by crystal growth. However, fluorides are susceptible to hydrolysis and during high temperature reactions OH − ions may get incorporated which is detrimental for optical properties. A coprecipitation synthesis of KMgF 3 from MgCl 2 solution using KF as a precipitating agent is described. KMgF 3 based phosphors incorporating a variety of activators like Ce 3+ , Eu 2+ , Sm 2+ , V 2+ were successfully prepared. These show excellent luminescence properties consistent with the literature. A variety of phenomena like photoluminescence, thermoluminescence, optically stimulated luminescence were exhibited by KMgF 3 :Eu 2+ prepared by the coprecipitation method. [ABSTRACT FROM AUTHOR]

The strontium-doped lanthanum manganites (La 1- x Sr x MnO 3 , LSMO) have potential use in devices for energy conversion and storage due to their chemical stability and high electrical conductivity. In this study, LSMO (x = 0, 0.1, 0.2, 0.3) were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis. The formation of the LSMO phase was confirmed by X-ray diffraction and the lattice parameters were determined by Rietveld refinement analysis. The oxygen nonstoichiometry in samples was determined by permanganate titration. The results of electrical conductivity measurement have shown semiconductor behaviuor in all samples, with conductivity rising with temperature and Sr-amount. Furthermore, it was observed that LSMO samples prepared by the coprecipitation method possess higher conductivity than samples prepared with the CNA method due to the higher oxygen nonstoichiometry. Electrical conductivities of all LSMO samples were in 10−2–0.45 Ω−1 cm−1 range, which is comparable to the conductivity of Si. • LSMO were prepared using 2 different methods: autocombustion and coprecipitation. • Coprecipitated samples possess higher oxygen nonstoichiometry and conductivity. • Prepared LSMO materials possess conductivity comparable to the pure Si. • Coprecipitation is suitable for the preparation of semiconducting LSMO ceramics. [ABSTRACT FROM AUTHOR]

Abstract: Samples of cubic shaped nanocrystalline LiF:Mg, LiF:Cu, LiF:P and LiF:Mg, Cu, P materials were synthesized through the chemical coprecipitation route. In case of LiF:Cu, it was predominantly doped with Cu2+ and Cu+ impurities using CuCl2 and Cu2Cl2 salts, respectively, as dopants. The samples were characterized by XRD, SEM and TEM techniques. The particle size observed from TEM photographs and XRD analysis was found to be in the range of 50–80nm. Samples were annealed at different ambient temperatures in the range of 373–773K. The pellets of these materials were exposed to γ-rays in the dose range (0.1Gy–100kGy) from 137Cs source for further studies. Thermoluminescence (TL) glow curves of these nanocrystalline samples show two main peaks one at around 404K and another broad peak centered at around 490K. The relative intensities of these peaks were found to change on doping with CuCl2 and Cu2Cl2. Comparison with commercially available TLD phosphors showed that TLD-700H and TLD-900 are more sensitive while, TLD-100 is less sensitive than LiF:Cu+ phosphor. The change in glow curve structures and the photoluminescence (PL) spectra revealed that the relative concentrations of the Cu2+ ↔Cu+ ↔Cu0 change irreversibly during irradiation, while taking TL readouts and during annealing beyond 523K. It seems that such redox reactions are responsible for the changes in the sensitivity and the loss of the reusability of the phosphor as Cu+ is necessary for the high sensitivity of the phosphor. Further detailed studies by taking glow curve readouts up to different temperatures, irradiating again and taking TL readouts show that the remaining traps after the first readout could change the Cu2+/Cu+ ratio altering the glow curve structure. The PL spectra and ESR measurements of the irradiated samples also support these findings. It may be concluded that redox reactions are mainly responsible for the loss of sensitivity and reusability on taking TL after 523K in case of LiF:Cu+ and LiF:Mg, Cu, P TLD phosphors. A model representing the redox reactions illustrates the TL phenomenon occurring in LiF:Cu+ phosphor. [Copyright &y& Elsevier]

Abstract: Microscale Li[Li0.19Ni0.16Co0.08Mn0.57]O2 powders with a high tap density were synthesized using [Ni0.2Co0.1Mn0.7]O x precursor with a unique microstructure via coprecipitation in flowing air. The synthesized Li[Li0.19Ni0.16Co0.08Mn0.57]O2 powders were composed of spherical nanosized primary particles, which results in a high tap density due to the high packing of the spherical primary particles. When used as electrode in a lithium cell, Li[Li0.19Ni0.16Co0.08Mn0.57]O2 exhibits a very high gravimetric capacity of 263mAhg−1 and a volumetric capacity of 956mAhcm−3, as well as an excellent rate capability delivering a discharge capacity of 202mAhg−1 at a 2C-rate. TEM analysis together with SEM observations show that the electrochemical performance of the Li[Li0.19Ni0.16Co0.08Mn0.57]O2 electrode is primarily governed by its microstructure. [Copyright &y& Elsevier]

To improve the conductivity of YO-stabilized ZrO (YSZ) based oxygen-ion conductor, ZrYO-LaSiO (YSZ-LSO) composite ceramics with the mass fraction of LaSiO (LSO) of 15% were prepared by using a modified coprecipitation method. The phases, microstructures and conductivities of the YSZ, LSO and YSZ-LSO were investigated by X-ray diffraction, electron microscopy and complex impedance, respectively. The results show that the as-calcined powder of YSZ-LSO composite has the grain size less than 10 nm, and the as-sintered composite ceramics are composed of YSZ and LSO phases. The conductivity can be enhanced obviously by composite method. At 700 °C, the conductivity of the composite ceramic is 0.125 S/cm, which is one order in magnitude higher than that of the YSZ ceramic and two orders in magnitude higher than that of LSO ceramic. By analyzing the impedance spectra and modulus spectra, the interfacial effect on the conductivity improvement was proposed. [ABSTRACT FROM AUTHOR]

A small change in crystal structural leads towards a significant improvement in absorption, emission, magnetic nature and electrical properties of ZnO. The present work focuses on studying of Dy+3 doping on structural parameters and absorption analysis of ZnO nanoparticles. Different concentrations of Dy (0–3%) doped ZnO nanoparticles have been synthesized by co-precipitation method without any impurity phase to analyze the role of dysprosium doping concentration on HCP structure of ZnO nanoparticles. We observed variation in structural parameters indicating small deformation due to Dy doping. Absorption spectra specify a slight variation in optical bandgap caused by doping Dy+3. The FTIR peak at 600 cm−1 confirms the ZnO HCP structure. The Dy doping results a wave number shift towards the higher side. The change in wave number is due to atomic mass difference. The study indicates a correlation between variation in absorption spectra and structural deformation. •Dy(0-3%) doped ZnO prepared by coprecipitation without any impurity phase. •Rietveld refinement indicate slight deformation in crystal structure. •UV region absorption increases due to increase in Dy induced defects. •FTIR analysis confirms the substitution of Dy by wavenumber variation. [ABSTRACT FROM AUTHOR]

Abstract: Polycrystalline gadolinium gallium mixed oxides were prepared by coprecipitation and annealing at various temperatures below 1000°C. The oxide materials appear to be X-ray amorphous after a heat treatment at 500°C for 30h, but after 30h at 800 and 900°C a major, unreported, hexagonal phase, isostructural with TAlO3 compounds (where T=Y, Eu, Gd, Tb, Dy, Ho, Er) appears to crystallize. On the other hand, a highly energetic mechanical treatment of the amorphous powder previously annealed at 500°C changes considerably the shape and position of exothermal events occurring in the range from 700 up to 900°C. Subsequent annealing at 900°C of the mechanically treated powder gives rise to the complete formation of the Gd3Ga5O12 garnet structure at the expense of the hexagonal phase and of the minor Gd4Ga2O9 oxide phase. However, a 7.0wt% contamination is found to be due to tetragonal zirconia coming from vials and balls colliding media. The garnet phase may have strong deviations from the nominal stoichiometry of the garnet, as suggested by the refined lattice parameter obtained from the powder diffraction patterns and by the remarkable absence of intensity relative to the (220) Bragg peak position. [Copyright &y& Elsevier]

NaMgF 3 -based phosphors have been described frequently in the literature. Their synthesis faces difficulties typical of fluoride materials. A simple precipitation synthesis for NaMgF 3 -based phosphors is described in this paper. This consisted of mixing aq. NaF and MgCl 2 /MgSO 4 solutions. Various activators could be incorporated by adding the required salts during this process. Characteristic emission of the activators was observed in the prepared phosphors. As-prepared samples exhibited predominantly trivalent lanthanide emission. After thermal treatment in a reductive atmosphere, europium-doped samples showed the intense emission of Eu 2+ . By virtue of the intense nature of the emission, lifetime measurements could be made for this sample. Notably, intense thermoluminescence and optically stimulated luminescence were observed in NaMgF 3 :Eu. A simple, fast method for the synthesis of NaMgF 3 was therefore developed., (© 2021 John Wiley & Sons, Ltd.)

Sodium-rich iron hexacyanoferrates were prepared by coprecipitation, hydrothermal route, and under reflux, with or without dehydration. They were obtained with different structures described in cubic, orthorhombic, or rhombohedral symmetry, with variable compositions in sodium, water, and cationic vacancies and with a variety of morphologies. This series of sodium-rich Prussian blue analogues allowed addressing the relationship between synthesis conditions, composition, structure, morphology, and electrochemical properties in Na-ion batteries. A new orthorhombic phase with the Na 1.8 Fe 2 (CN) 6 ·0.7H 2 O composition synthesized by an hydrothermal route at 140 °C is reported for the first time, whereas a phase of Na 2 Fe 2 (CN) 6 ·2H 2 O composition obtained under reflux, previously described with a monoclinic structure, shows in fact a rhombohedral structure.

The removal of herbicides from water by photocatalysis is essential for environmental remediation. Moreover, optimization of ecofriendly photocatalysts is an alternative approach. Here, we synthesized Cu 2 O nanoparticles utilizing a sol-gel technique, which were subsequently loaded with Cu nanoparticles to form Cu@Cu 2 O by simple photoassisted deposition with different Cu contents. The prepared nanostructures showed an increase in light absorption at longer wavelengths and a reduction in the bandgap from 2.08 eV in pure Cu 2 O to 1.95 eV in 15% Cu-loaded Cu 2 O. The photoluminescence and photocurrent experiments suggest the lowest recombination of photoinduced charges through optimizing the Cu content. The amended Cu@Cu 2 O led to the complete photodestruction of atrazine, a commonly applied triazine herbicide, after 30 min of visible light exposure with outstanding durability. Image 1 • Cu-supported Cu 2 O nanoparticles prepared by a simple route. • Cu improved structural and surface texture of the Cu 2 O. • Photodeposited Cu boosts visible light absorption and sinks the photoexcited electrons. • Optimized Cu–Cu 2 O showed 100% destruction of atrazine after 30 min light. • Invented photocatalyst display outstanding recyclability for water remediation. [ABSTRACT FROM AUTHOR]

Abstract: A carbonate coprecipitation synthesis, simple and easily scalable to industrial level, has been successfully applied to produce Sr- and Mg-doped LaGaO3. The thermal evolution shows that the main perovskite phase crystallizes already at 1000 °C. Samples sintered at 1400 °C for 10 h have a relative density of 93% and an electrical conductivity of 7.7∙10−2 S cm−1 at 800 °C, similar to the one reported for solid state synthesis. The presence of small amounts of secondary phases (about 17%) such as LaSrGaO4 and LaSrGa3O7 does not seem to deeply affect the electrical properties of the final material. [Copyright &y& Elsevier]

Hybrid magnetite/maghemite nanoparticles (MNP) coated with waste-sourced bio-based substances (BBS) were synthesized and studied for the degradation of phenol, chosen as a model pollutant, in water. A systematic study was undertaken in order to rationalize MNP–BBS behavior and optimize their performance. The effect of experimental parameters, such as light irradiation, addition of hydrogen peroxide, and the ratio between hydrogen peroxide and MNP–BBS concentrations, was studied. The generation of hydroxyl radicals was assessed, and the recovery and re-cycle of the material was investigated. Our results indicate that phenol degradation could be attained by both Fenton and photo-Fenton processes, with higher efficiency in dark condition and in the presence of a suitable amount of hydrogen peroxide. Evidence was obtained for the roles of iron ions leached from the materials as well as of organic matter released in the solution upon partial photodegradation of the organic coating. The reusability tests indicated a lower but still valid performance of the material. Optimization of the experimental conditions was performed to achieve the highest efficiency in substrate degradation, and fundamental insights into the mechanism of the MNP–BBS Fenton-like reaction were obtained. [ABSTRACT FROM AUTHOR]

Considerable efforts have been focused on the exploitation of macromolecule ligands for synthesis of magnetic Fe3O4 nanoparticles as T1 magnetic resonance imaging (MRI) contrast agents, but studies that concern macromolecule ligands with different charges and coordination groups are still limited. Herein, we used poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and polyvinyl alcohol (PVA), which possess negative, positive and neutral charges with carboxylic acid, amino and hydroxyl groups respectively, as templates and stabilizers to fabricate Fe3O4 nanoparticles through coprecipitation reaction. The obtained Fe3O4-PAA, Fe3O4-PAH, and Fe3O4-PVA nanoparticles showed T1 contrast performance with r1 relaxivities of 23.4, 60.3, and 30.6 mM s−1 at 0.5 T (25 °C), and a r2/r1 ratio of 2.62, 3.82, and 7.26, respectively. The cell viability assay revealed that Fe3O4-PAA and Fe3O4-PVA exhibited good biocompatibility, while Fe3O4-PAH displayed high cytotoxicity. In vivo T1-weighted (1 T) mice showed that both Fe3O4-PAA and Fe3O4-PVA were able to display remarkably brighten the contrast enhancement for the mice tumor and kidney sites, but Fe3O4-PAA had better contrast performance. This work highlights that the macromolecule ligands play an important role in the biocompatibility and T1 contrast performance of magnetic Fe3O4 nanoparticles. [ABSTRACT FROM AUTHOR]