Synthesis and Characterization of Superparamagnetic NiBaO<Subscript>2</Subscript> Nano-Oxide Using Novel Precursor Complex [Ba(H<Subscript>2</Subscript>O)<Subscript>8</Subscript>][Ni(dipic)<Subscript>2</Subscript>]

In this paper, for the first time, synthesis of [Ba(H₂O)₈][Ni(dipic)₂] complex and preparation of NiBaO₂ nano-oxide are reported through thermal decomposition under surfactant free condition. This novel complex was characterized by Fourier transform infrared spectroscopy (FT-IR), ultra violet–visible spectroscopy, conductivity measurement and elemental analysis. Formation of novel nanoparticles was supported by FT-IR and energy-dispersive X-ray spectroscopy and the orthorhombic structure of nanocrystals was confirmed by powder X-ray diffraction analysis. In addition, size distribution as well as uniform morphology of prepared nano-oxide were recorded by dynamic light scattering analysis and field-emission scanning electron microscopy, respectively. Magnetic features measured by vibrating sample magnetometer, illustrate superparamagnetic behavior of the oxide.     

Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@SiO<Subscript>2</Subscript>@TiO<Subscript>2</Subscript>-OSO<Subscript>3</Subscript>H: an efficient hierarchical nanocatalyst for the organic quinazolines syntheses

A sulfonic acid functionalized titanium dioxide quasi-superparamagnetic nanocatalyst Fe₃O₄@SiO₂@TiO₂-OSO₃H with average size of 61 nm and semispherical shape with surface area about 97 m² g^?1 with saturation magnetization 17.7 emu g^?1 and the coercivity 9.84 Oe was successfully synthesized. The structure and morphology of the nanocatalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy, X-ray diffraction pattern, transmission electron microscopy, field-emission scanning electron microscopy, vibrating sample magnetometer and Brunauer–Emmett–Teller surface area analysis. The catalytic usage of the nanocatalyst was exemplified in synthesis of 2,3-dihydroquinazolin-4(1H)-one and spiroquinazolin-4(3H)-one derivatives in deep eutectic solvents (DESs) based on choline chloride and urea. We suggest that the synergistic effects in catalytic activities of titanium dioxide, organic acid and the CO₂ capture property of DES are the main reasons for the improvement of catalytic activity. The synthesized spiroquinazolinones and dihydroquinazolinones derivatives were characterized by FT-IR, ¹H and ¹³C nuclear magnetic resonance spectroscopy. The magnetic nanocatalyst exhibit high catalytic activity and can be simply separated from reaction media by an external magnet in a few seconds and could be reused for six cycles without significant loos in activity, which indicates the good immobilization of sulfonic acid on the magnetic titanium dioxide support. Furthermore, the solvent which has been used in this work can be readily isolated and reused for several times.     

One-pot method fabrication of superparamagnetic sulfonated polystyrene/Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/graphene oxide micro-nano composites

In this work, using monodispersed sulfonated polystyrene (SPS) microspheres as carriers, FeCl₃·6H₂O and FeSO₄·7H₂O as precursors, NaOH as precipitant in the presence of graphene oxide (GO), SPS/Fe₃O₄/GO micro-nano composites were fabricated by a simple one-pot method employing an inverse coprecipitation in-situ compound technology. The SPS/Fe₃O₄/GO micro-nano composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffractometer, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms and vibrating sample magnetometer. The results show that the SPS/Fe₃O₄/GO micro-nano composites were fabricated with SPS as core, GO and Fe₃O₄ nanoparticles as shell. The SPS/Fe₃O₄/GO micro-nano composites had larger BET specific surface area, average pore width and micropore volume than the pure SPS microspheres. Meanwhile, the SPS/Fe₃O₄/GO micro-nano composites had superparamagnetism and hydrophilic property. The saturation magnetization (M_s) of the SPS/Fe₃O₄/GO micro-nano composites was 10.86 emu/g, which was enough to ensure the convenient magnetic separation of solid and liquid phase.     

A Novel 3D Photoactive Coordination Polymer with Alternate Cd(H<Subscript>2</Subscript>O)<Superscript>2+</Superscript> and Mg(Hen)<Superscript>3+</Superscript> Units and Sandwich-Shaped Cluster Linkages

A novel organic–inorganic hybrid, cadmium(II)-magnesium(II)-molybdenum(V) phosphate, {Cd[(PO₄)₂(HPO₄)₂Mo₆O₁₁(OH)₄]₂}[Cd(H₂O)]₂[Mg(Hen)]₂{Cd[(PO₄)₃(HPO₄)Mo₆O₁₀(OH)₃Cl₂]₂}·(H₂en)₄·(Hen)₂·(en)₂·9H₂O (en = ethylenediamine), was prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis, inductively coupled plasma (ICP) analysis, thermogravimetric analysis, fluorescence, FT-IR and bond valence sum calculations. As revealed by single-crystal X-ray diffraction studies, the sandwich-shaped clusters of [Cd(Mo₆P₄)₂] are interconnected by additional [Mg(Hen)] units and [Cd(H₂O)] fragments to form an extended three-dimensional supramolecular framework with channels occupied by ethylenediamine molecules, protonated ethylenediamine cations and water molecules. Luminescent measurement of the title compound exhibits intensive blue and greenish-blue radiation emission upon excitation with ultraviolet light.     

Preparation and characterization of spindle-like Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> mesoporous nanoparticles

Magnetic spindle-like Fe₃O₄ mesoporous nanoparticles with a length of 200 nm and diameter of 60 nm were successfully synthesized by reducing the spindle-like α-Fe₂O₃ NPs which were prepared by forced hydrolysis method. The obtained samples were characterized by transmission electron microscopy, powder X-ray diffraction, attenuated total reflection fourier transform infrared spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and nitrogen adsorption-desorption analysis techniques. The results show that α-Fe₂O₃ phase transformed into Fe₃O₄ phase after annealing in hydrogen atmosphere at 350°C. The as-prepared spindle-like Fe₃O₄ mesoporous NPs possess high Brunauer-Emmett-Teller (BET) surface area up to ca. 7.9 m² g^-1. In addition, the Fe₃O₄ NPs present higher saturation magnetization (85.2 emu g^-1) and excellent magnetic response behaviors, which have great potential applications in magnetic separation technology.     

Modification of Cu/Zn/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Catalyst by Activated Carbon Based Metal Organic Frameworks as Precursor for Hydrogen Production

In this study, Cu/Zn/Al₂O₃-AC (AC?=?activated carbon) catalyst was synthesized and evaluated for dimethoxymethane (DMM) reformation to hydrogen. The Cu/Zn/Al₂O₃-AC catalyst was prepared using high surface area metal organic frameworks (MOFs) consisting of Cu₃(BTC)₂ (MOF-199) and Zn₄O(BDC)₃ (MOF-5) for Cu(II) and Zn(II) sources respectively, as precursors while γ-Al₂O₃ was applied as support. The synthesized catalyst was investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer–Emmett–Teller analysis (BET), Temperature programmed desorption (NH₃-TPD) and Energy-dispersive X-ray spectroscopy (EDX) techniques. Complete DMM conversion was observed over Cu/Zn/Al₂O₃-AC catalyst (Cu:Zn:Al mole ratio of 6:3:2) under atmospheric pressure, T?=?533 K, GHSV?=?20 NL h^?1 g_cat^?1, N₂/H₂O/DMM?=?24/5/1 volume percent (vol%) with hydrogen productivity of 12.8 L H₂ h^?1 g_cat^?1 and 64% hydrogen concentration. Application of MOFs as precursors and modified activated carbon as an acidic component provided the catalyst with the porous structure and high specific surface area for the hydrolysis of DMM, subsequently, high selectivity and productivity of hydrogen was obtained.     

Synthesis,characterization and electrical properties of polypyrrole/V<Subscript>2</Subscript>O<Subscript>5</Subscript> composites

Polypyrrole (PPy) and its composites with vanadium pentoxide (V₂O₅) were synthesized in aqueous medium by chemical oxidation polymerization using FeCl₃·6H₂O as an oxidant. The materials were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometry (XRD), thermogravimetry analyzer (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), UV/visible spectroscopic techniques and LCR-meter. The FT-IR results confirmed the successful synthesis of PPy and PPy/V₂O₅ composites. The XRD study showed the amorphous and crystalline nature of PPy and PPy/V₂O₅ composites, respectively. The TGA analysis showed slight increase in the thermal stability of the composites. The SEM data verified the porous nature of PPy and the composites. The UV/visible spectrometry confirmed the doping of PPy in composites. The electrical properties of the materials displayed their semiconducting nature. The resistance of the samples was found to be dependent on temperature and the contents of V₂O₅ in the composites.     

Synthesis and Photocatalytic Performance of Bi<Subscript>12</Subscript>O<Subscript>17</Subscript>Cl<Subscript>2</Subscript> Semiconductors Calcined at Different Temperatures

In the current investigation a series of oxygen-rich bismuth oxychloride Bi₁₂O₁₇Cl₂ samples through an ethylene glycol-solvothermal route were constructed at different calcination temperatures and fully characterized by X-ray diffraction patterns, scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectra, X-ray energy dispersion spectroscopy, and photoluminescence spectra. It was demonstrated that the calcination temperatures indeed had a crucial effect on the crystallinity, grain size, morphology, optical property, and charge carrier separation of Bi₁₂O₁₇Cl₂ series. These Bi₁₂O₁₇Cl₂ samples showed significantly improved photocatalytic degradation over dye Rhodamine B and colorless antibiotic tetracycline hydrochloride. Particularly, the best candidate, the sample 350 °C—Bi₁₂O₁₇Cl₂ could show apparent reaction rate constants that were nearly 28.2, 1.2 times of N–TiO₂ over Rhodamine B and tetracycline hydrochloride, respectively. The possible reason of enhancing photocatalytic performance by various Bi₁₂O₁₇Cl₂ samples calcined at different temperatures was discussed and major oxidative radicals maybe generated during photocatalytic processes were detected.     

Ultrasound and Microwave-Assisted Co-precipitation Synthesis of La<Subscript>0.75</Subscript>Sr<Subscript>0.25</Subscript>MnO<Subscript>3</Subscript> Perovskite Nanoparticles from a New Lanthanum(III) Coordination Polymer Precursor

In the present study nano-sized strontium-doped lanthanum manganite, La_0.75Sr_0.25MnO₃ (LSM), were synthesized by three simple different methods (a) co-precipitation, (b) ultrasonic and (c) microwave-assisted co-precipitation. A lanthanum(III) coordination polymer, [pyda.H]₂[La₂(pydc)₄(H₂O)₄]·2H₂O, where [pyda.H]⁺?=?2,6-diaminopyridinium, and (pydc)^2??=?2,6-pyridinedicarboxylate, was used as a new precursor. The products were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), thermal gravimetric (TG) and differential thermal analyses (DTA), as well as by Energy-dispersive X-ray spectroscopy (EDX). The XRD results showed that the crystal lattice of the product obtained was orthorhombic perovskite structure. The porosity, particle size and homogeneity of calcinated LSM were strongly dependent on the preparation method. In addition, the results proved that the product formation time was decreased considerably when ultrasonic or microwave irradiation methods were used.     

Preparation and electromagnetic properties of the BaFe12O19/multiwall carbon nanotubes/poly(3‐methyl‐thiophene) composites

The BaFe₁₂O₁₉/multiwall carbon nanotubes/poly(3‐methyl‐thiophene) (BaFe₁₂O₁₉/MCNTs/P(3MT)) composites were synthesized through an in situ chemical polymerization of 3‐methyl‐thiophene (3MT) in the presence of BaFe₁₂O₁₉/MCNTs composite powders. The BaFe₁₂O₁₉/MCNTs/P(3MT) composites were characterized by the fourier transform infrared spectrometry (FTIR) and X‐ray diffraction (XRD). The morphologies of the composites were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electric conductive properties were tested by a four‐probe conductivity tester and the magnetic properties were measured by vibrating sample magnetometer (VSM). The electromagnetic performance tests showed that when the mass ratio of BaFe₁₂O₁₉ to MCNTs was 0.4, and the BaFe₁₂O₁₉/MCNTs to P(3MT) was 0.15, the conductivity, saturation magnetization (M_s) and residual magnetization (M_r) of the BaFe₁₂O₁₉/MCNTs/P(3MT) composites achieved 166.740 S/m, 29.884 emu/g, and 17.581 emu/g, respectively. POLYM. COMPOS., 34:1801–1808, 2013. © 2013 Society of Plastics Engineers     

Synthesis of spinel Ni<Subscript>0.75</Subscript>Zn<Subscript>0.25</Subscript>Fe<Subscript>2</Subscript>O<Subscript>4</Subscript> and the properties of a coating obtained by gas-flame spraying

Ferrite Ni_0.75Zn_0.25Fe₂O₄ was prepared by the solid-state synthesis and thermal decomposition of the complex oxalate Ni_0.75Zn_0.25Fe₂(C₂O₄)₃ · 6H₂O. The oxalate precursor and the products obtained at different stages of the thermal decomposition were identified by differential thermal analysis and X-ray and X-ray photoelectron spectroscopy. The properties of a ferromagnetic coating deposited on a substrate by gasflame coating were studied. The magnetic properties of the Ni-Zn ferrite product and the ferromagnetic coating were also investigated.     

Low-Temperature Preparation of Superparamagnetic CoFe<Subscript>2</Subscript>O<Subscript>4</Subscript> Microspheres with High Saturation Magnetization

Based on a low-temperature route, monodispersed CoFe₂O₄ microspheres (MSs) were fabricated through aggregation of primary nanoparticles. The microstructural and magnetic characteristics of the as-prepared MSs were characterized by X-ray diffraction/photoelectron spectroscopy, scanning/transmitting electron microscopy, and vibrating sample magnetometer. The results indicate that the diameters of CoFe₂O₄ MSs with narrow size distribution can be tuned from over 200 to ~330 nm. Magnetic measurements reveal these MSs exhibit superparamagnetic behavior at room temperature with high saturation magnetization. Furthermore, the mechanism of formation of the monodispersed CoFe₂O₄ MSs was discussed on the basis of time-dependent experiments, in which hydrophilic PVP plays a crucial role.     

Effects of La<Subscript>2</Subscript>O<Subscript>3</Subscript> on ZrO<Subscript>2</Subscript> supported Ni catalysts for autothermal reforming of CH<Subscript>4</Subscript>

The effect of La₂O₃ content in Ni-La-Zr catalyst was investigated for the autothermal reforming (ATR) of CH₄. The catalysts were prepared by the coprecipitation method and had a mesoporous structure. Temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) indicated that a strong interaction developed between Ni species and the support with the addition of La₂O₃. Thermogravimetric analysis (TGA) and H₂-pulse chemisorption showed that the addition of La₂O₃ led to well dispersed NiO molecules on the support. Ni-La-Zr catalysts gave much higher CH₄ conversion than Ni-Zr catalyst. The Ni-La-Zr containing 3.2 wt% La₂O₃ showed the highest activity. The optimum conditions for maximal CH₄ conversion and H₂ yield were H₂O/CH₄=1.00, O₂/CH₄=0.75. Under these conditions, CH₄ conversion of 83% was achieved at 700 °C. In excess O₂ (O₂/CH₄>0.88), the catalytic activity was decreased due to sintering of the catalyst.     

Mg(OH)<Subscript>2</Subscript> Films Prepared by Ink-Jet Printing and Their Photocatalytic Activity in CO<Subscript>2</Subscript> Reduction and H<Subscript>2</Subscript>O Conversion

Mg(OH)₂ films on Al substrates were fabricated by ink-jet printing, and they were applied as photocatalysts in solar fuels production (H₂ and CH₃OH) from CO₂ and H₂O conversion. The films were fabricated by means of a deposition of a solution composed of magnesium complex nanoparticles over aluminum foils, which were submitted to a heat treatment to promote the crystallization of Mg(OH)₂. The films were characterized by razing incidence X-ray diffraction (GZXD), Fourier-transform infrared spectroscopy (FTIR), Scanning electronic microscopy, X-ray photoelectron spectroscopy (XPS), and N₂ physisorption by BET method. The Mg(OH)₂ was detected in all the samples synthesized with 1 to 40 layers. According to XPS and FTIR analysis, it was detected the presence of carbonates related to Mg₃O(CO₃)₂ and Al⁰ and Al³⁺ due to the substrate. The highest photocatalytic activity was reached using 30 layers of Mg(OH)₂ for H₂ and CH₃OH generation, which it was 268 and 15 µmol g^??1h^??1, respectively. These results were associated to the presence of adequate amounts of MgO and Al₂O₃ that promote an efficient transfer of the photogenerated electrons between them. Furthermore, the formation of porous structures with high surface area and relative high roughness promoted an increase in the mass transport between the gas and liquid phase, which increase the effectiveness of the photocatalysts.     

High Performance Removal of Anionic and Cationic Dye Pollutants with Co<Subscript>3</Subscript>O<Subscript>4</Subscript> Modified Nanoclinoptilolite: Kinetics and Adsorption Equilibrium Studies

In this paper Co₃O₄ doped nanoclinoptilolite was synthesized and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. The adsorption efficiency for removing of methylene blue was about 95% in 10 min. The effect of some factors such as adsorbent dose, concentration of analyte and pH was investigated for enhancing the removing efficiency. Moreover Freundlich and Langmuir patterns were plotted for this new nanocomposite. Maximum of adsorption capacity was obtained from slope of Langmuir and was about 25 mg/g. The kinetic study for methylene blue shows a second order kinetic with rate constant about 0.02 g/mg/min. The prepared nanocomposite was successfully applied for removing some color compounds such as methylene blue, methyl green, and methyl red and also binary dye mixtures.     

Mercury ion adsorption on AC@Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>-NH<Subscript>2</Subscript>-COOH from saline solutions: Experimental studies and artificial neural network modeling

An efficient, novel functionalized supported magnetic nanoparticle (AC@Fe₃O₄-NH₂-COOH) has been synthesized by co-precipitation method for removal of mercury ions from saline solutions. High dispersed supported magnetic nanoparticles with particle sizes less than 30 nm were formed over activated carbon derived from local walnut shell. Surface characterizations of supported magnetic nanoparticles were evaluated by Boehm test, Brunauer- Emmett-Teller (BET) surface area, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray fluorescence (XRF). A three-layer artificial neural network (ANN) code was developed to predict the Hg (II) ions removal from aqueous solution by AC@Fe₃O₄-NH₂-COOH. The three-layer back-propagation (BP) is configured of tangent sigmoid transfer function (tansig) at hidden layer with eight neurons for AC@Fe₃O₄-NH₂-COOH, and linear transfer function (purelin) at output layer. According to the calculated MSEs, Levenberg-Marquardt algorithm (LMA) was the best training algorithm among others. The linear regressions between the predicted and experimental outputs were proven to be a good agreement with a correlation coefficient of about 0.9984 for five model variables. Maximum adsorption capacity was achieved 80mg/g by Langmuir isotherm at pH of 7 and salinity of 25,000 ppm. Kinetic studies illustrated that mercury adsorption follows pseudo-second-order.     

Synthesis and thermal behavior of Fe<Subscript>3</Subscript>O<Subscript>2</Subscript>(BO<Subscript>4</Subscript>) oxoborate

Iron oxoborate Fe₃O₂(BO₄) has been first produced in solid-phase chemical reactions. Its thermal behavior in the temperature range 20–900°C is studied with the use in-situ high-temperature powder X-ray diffraction. It is shown that Fe₃O₂(BO₄) begins decomposing with the formation of Fe₂O₃ in the temperature range 660–900°C. Thermal expansion is sharply anisotropic at room temperature (α_max/α_min = 7) and becomes more isotropic with an increase in the temperature (α_max/α_min = 1.2). The degree of oxidation of Fe³⁺ has been confirmed by Mössbauer spectroscopy (at a room temperature), and two nonequivalent positions in the structure have been detected, which are occupied by iron atoms with the octahedral environment of the oxygen atoms.     

Crystal structure of new compound (Rb,K)<Subscript>2</Subscript>Cu<Subscript>3</Subscript>(P<Subscript>2</Subscript>O<Subscript>7</Subscript>)<Subscript>2</Subscript>

A new compound of (Rb,K)₂Cu₃(P₂O₇)₂ is obtained by high-temperature reactions from a mixture of RbNO₃, KNO₃, Cu(NO₃)₂, and (NH₄)₄P₂O₇. The crystal structure was solved by direct methods and refined to R ₁ = 0.056 for 5022 independent reflections. The compound belongs to a rhombic crystal system, P2₁2₁2₁, Z = 8, a = 9.9410(7) Å, b = 13.4754(6) Å, c = 18.6353 (3) Å, and R = 0.056. The basis of the structure is a complex copper-phosphate skeleton of the composition of [Cu₃(P₂O₇)₂]^2–, which can be regarded as consisting of two types of heteropolyhedral layers parallel to the (001) plane. The layers are alternated with each other, forming a frame, in the cavities of which the positions of alkali cations are located, statistically populated with K⁺ and Rb⁺ ions. Based on the refined populations of the positions of alkali cations, an exact chemical formula of the compound can be written as Rb_1.28K_0.72Cu₃(P₂O₇)₂. The compound is the most complex among those known to this day of the composition of A₂ ^IB₃ ^II(P₂O₇)₂ (A = Li, Na, K, Rb, or Cs; B = Ni, Cu, or Zn).     

Synthesis and Characterization of Sulfamic-Acid Functionalized Magnetic Fe3O4 Nanoparticles Coated by Poly(amidoamine) Dendrimer

Grafting of chlorosulfuric acid on the amino-functionalized Fe₃O₄ nanoparticles produced sulfamic acid-functionalized magnetic Fe₃O₄ nanoparticles as a novel organic–inorganic hybrid material, which was characterized with X-ray diffractometry (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, scanning electron spectroscopy, and magnetization measurements (VSM). The as-prepared nanocomposite with a narrow size distribution has the crystallite size from XRD (11 ± 4 nm) and particle size from TEM analysis (12.9 ± 0.4 nm) are consistent with each other. Magnetization measurements proved the superparamagnetic property of the product.     

Zr K-edge XAS study on ZrO<Subscript>2</Subscript>-pillared aluminosilicate

The ZrO₂-pillared clay with high acidic property has been prepared by reacting 1 wt% colloidal suspension of Na⁺-montmorillonite with 1 N aqueous solution of ZrOCl₂·8H₂O and by subsequent heating. The evolution of local structure around zirconium of the intercalant stabilized in-between aluminosilicate layers upon intercalating, drying, and pillaring condition has been systematically studied by X-ray absorption spectroscopy, and compared to those of reference compounds such as ZrO₂, and ZrOCl₂ · 8H₂O and its 1 N aqueous solution. The intercalated zirconium species was identified as the Zr-tetramer, [Zr₄(OH)₁₄(H₂O)₁₀]²⁺, with an average molecular volume of 10 × 10 Å² and a thickness of 4.5 Å. Also it becomes more condensed upon drying and eventually transforms to a zirconium oxide pillar upon calcination.