Showing papers in "Journal of Cluster Science in 2013"
TL;DR: In this paper, the effect of some parameters on particle size distribution and determine the optimum conditions for preparing chitosan nanoparticles by ionic gelation, followed by evaluation of the physicochemical and structural properties.
Abstract: In this research, chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. Effects of parameters such as chitosan concentration, tripolyphosphate concentration, and reaction time on the particle size distribution were investigated. In order to determine optimum conditions, tests were designed by Qualitek-4 software, using Taguchi method. The best conditions were determined based on three factors at three levels. Therefore, the main object was to investigate the effect of some parameters on particle size distribution and determine the optimum conditions for preparing chitosan nanoparticles by ionic gelation, followed by evaluation of the physicochemical and structural properties. The size distribution of original chitosan and chitosan nanoparticles were determined by Laser Diffraction and Dynamic Light Scattering, respectively. The physicochemical properties of the chitosan nanoparticles were studied using SEM, TEM, XRD pattern, FTIR, UV–vis, TGA, and NMR spectra. The optimum chitosan concentration, tripolyphosphate concentration, and reaction time were found to be 1.0 mg/ml, 1.0 mg/ml, and 60 min, respectively.
101 citations
TL;DR: In this article, the stability of zinc oxide (ZnO) nanoparticles suspended in a mixture of ethylene glycol and water with weight ratio of 40-60 as the base fluid is evaluated.
Abstract: Experimental studies are performed to evaluate the stability of zinc oxide (ZnO) nanoparticles suspended in a mixture of ethylene glycol and water with weight ratio of 40–60 as the base fluid. Different methods have been employed to disperse ZnO nanoparticles. It is found that using Gum Arabic leads to clustering and settle the nanoparticles. Also, the use of DI ammonium hydrogen citrate with weight ratio 1:1 (surfactant:nanoparticles) gives the acceptable stability. The density of nanofluids is measured and the results are compared with theoretical results. A helpful correlation for the measured densities of the stable nanofluids in a temperature range of 25–40 °C is presented which can used in practical applications. Finally based on the correlation a sensitivity analysis has been done. It is found that at higher temperatures the density is more sensitive to the increases in volume fraction.
74 citations
TL;DR: In this article, the H2S molecule can dissociate into H and SH fragments, suggesting that the nanocluster might be a potential catalyst for dissociation of the hydrogen sulfide molecule.
Abstract: Adsorption of hydrogen sulfide (H2S) on the external and internal surface of Zn12O12 nanocluster was studied by using density functional calculations. The results indicate that the H2S molecule is physically adsorbed or chemically dissociated by the nanocluster. It was found that the H2S molecule can dissociate into –H and–SH fragments, suggesting that the nanocluster might be a potential catalyst for dissociation of the H2S molecule. Also, dissociation of H2S to S species in internal surface of the Zn12O12 nanocluster is energetically impossible. The HOMO–LUMO energy gap of H2S dissociation configuration is changed about 27.68 %, indicating that the electronic properties of the nanocluster by dissociation process have strongly changed.
54 citations
TL;DR: In this paper, a simple sonochemical reaction at room temperature was used to synthesize metal hydroxide and metal carbonate nanoparticles with excellent performance in photocatalytic applications.
Abstract: In this work Mg(OH)2, Ca(OH)2, CaCO3, SrCO3 and BaCO3 nanoparticles were synthesized via a simple sonochemical reaction at room temperature. Nanoparticles were synthesized via a surfactant-free reaction solvent water. Nanostructures materials were characterized by scanning electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. The photocatalytic behavior of nanoparticles was evaluated using the degradation of a methyl orange aqueous solution under ultraviolet light irradiation. The results show that metal hydroxide and metal carbonate nanoparticles are promising materials with excellent performance in photocatalytic applications.
52 citations
TL;DR: In this article, the authors synthesized N,N′-(bis(salicylidene)-ethylene-1,2-diamine)Nickel(II); as precursor which has been synthesized via two methods: [Ni(salen)] were obtained by solid state reaction in absence solvent and co-precipitation reaction in presence of propanol as solvent, respectively.
Abstract: Nickel oxide nanoparticles have been synthesized by thermal treatment of N,N′-(bis(salicylidene)-ethylene-1,2-diamine)Nickel(II); [Ni(salen)]; as precursor which has been synthesized via two methods: [Ni(salen)] were obtained by solid state reaction in absence solvent and co-precipitation reaction in presence of propanol as solvent, respectively. Nickel oxide nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy.
45 citations
TL;DR: In this article, the formation of silver nanoparticles (AgNPs) is monitored by recording the UV-Vis absorption spectra for surface plasmon resonance (SPR) peak at ~450-nm.
Abstract: In the present study, Acacia farnesiana (Sweet acacia) seed extract is used to reduce Ag+ → Ag0 under microwave irradiation. The formation of silver nanoparticles (AgNPs) is monitored by recording the UV–Vis absorption spectra for surface plasmon resonance (SPR) peak at ~450 nm. The absorbance of SPR increases linearly with increasing temperature of the reaction mixture. Rapid reduction of silver ions occurred to form AgNPs, 80–90 % yield in about 150 s. A marginal decrease in pH and increase in solution potential (E) of the reaction mixture during the formation of AgNPs are in agreement with the proposed mechanism. XRD pattern of the AgNPs agree with the fcc structure of Ag metal, and the calculated crystallite size is ~17 nm. FT-IR and solid-state 13C NMR spectra indicate the functional groups of flavonones and terpenoids (biomolecules from plant extract) which are adsorbed on AgNPs, thereby the present method led to in situ biofunctionalization/bio-capping of AgNPs. TG analysis shows the thermal decomposition of these plant residues present on AgNPs at about 250 °C. The spherical shape of the particles with a diameter (ϕ) in the range of ~15–20 nm is evident from FE-SEM image. Elemental analysis by EDX analysis confirms the presence of Ag as the only major element. The in vitro antibacterial screening of AgNPs shows that these bio-capped AgNPs have higher inhibitory action for E. coli and S. aureus followed by B. subtilis and P. aeruginosa. In addition, AgNPs show very good antioxidant property.
43 citations
TL;DR: In this paper, the effect of plant-like magnesium hydroxide (Mg(OH)2) nanostructures on the thermal stability of polymeric matrixes has been investigated.
Abstract: Flower-like magnesium hydroxide (Mg(OH)2) nanostructures were synthesized via a simple hydrothermal reaction at relatively low temperature. The Mg(OH)2 nanostructures were then added to acrylonitrile–butadiene–styrene (ABS) and cellulose acetate (CA) polymers. The effect of Mg(OH)2 nanostructures on the thermal stability of the polymeric matrixes has been investigated. The thermal decomposition of the nanocomposites shifts towards higher temperature in the presence of the Mg(OH)2. The enhancement of thermal stability of nanocomposites is due to endothermically decomposition of magnesium hydroxide that releases of water and dilutes combustible gases. Nanostructures and nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), UL-94 test and limiting oxygen index (LOI) analysis.
42 citations
TL;DR: In this paper, the preparation and characterization of nickel oxide nanoparticles from nickel(II) Schiff base complexes as new precursors were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM).
Abstract: This study focuses on the preparation and characterization of nickel oxide nanoparticles from nickel(II) Schiff base complexes as new precursors. At first nickel(II) complexes [Ni(salophen)] and [Ni(Me-salophen)] were synthesized and characterized by elemental analyses and FT-IR spectroscopy. Then NiO nanoparticles were prepared by solid-state thermal decomposition at 550 oC for 3.5 h. The FT-IR spectrum confirmed the composition of products. The crystalline structures and morphology of products were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results revealed that the obtained products were nickel oxide. SEM and TEM images demonstrated that the NiO nanoparticles have uniform shape with size between 35 and 70 nm.
39 citations
TL;DR: In this article, copper sulfide nanoparticles have been synthesized from copper salicylate and thioglycolic acid by a hydrothermal method, and the obtained product was analyzed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive x-ray spectrograms, and photoluminescence spectrography.
Abstract: Copper sulfide nanoparticles have been synthesized from copper salicylate and thioglycolic acid by a hydrothermal method. The obtained product was analyzed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and photoluminescence spectroscopy. The effect of reaction time, temperature, solvent and sulfur sources was investigated.
33 citations
TL;DR: In this paper, a facile hydrothermal method for the preparation of three dimensional hollow ZnS nanostructures, using Zinc bis(salicyle aldehitato), Zn(Sal)2, thioacetamide (TAA) and thioglycolic acid (TGA) as Zn2+, sulfur source and capping agent, respectively.
Abstract: In this work, we report a facile hydrothermal method for the preparation of three dimensional hollow ZnS nanostructures, using Zinc bis(salicyle aldehitato), Zn(Sal)2, thioacetamide (TAA) and thioglycolic acid (TGA) as Zn2+, sulfur source and capping agent, respectively. The ZnS solid and hollow sphere was produced from the self-assembly of nanoparticles with diameters of 11 ± 2 nm with TGA and TGA, TAA, respectively. Furthermore, with changing zinc precursor from Zn(Sal)2 to zinc acetate [Zn(OAC)2], ZnS nanorods were obtained. The products were characterized by XRD, SEM, TEM, selected area electron diffraction, and FT-IR spectra. The influence of surfactant (Polyethylene glycol) on the morphology of the products was also investigated. Possible formation mechanism and optical properties of these architectures were also reported.
30 citations
TL;DR: In this article, the formation and morphology of the nanoparticles were studied using UV-visible spectroscopy, field emission scanning electron microscopy, and atomic force microscopy and the X-ray diffraction studies and energy dispersive Xray analysis indicate that the particles are crystalline in nature.
Abstract: In this research paper, we report on the rapid synthesis of silver nanoparticles using dried areca nut (Areca catechu). The microwave exposed aqueous areca nut powder when treated with the aqueous silver salt solution yielded irregular shaped silver nanoparticles. The formation and morphology of the nanoparticles are studied using UV–visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The X-ray diffraction studies and energy dispersive X-ray analysis indicate that the particles are crystalline in nature. The understanding of capping of biological moiety is derived from Fourier transform infrared spectroscopy and the thermogravimetric analysis. The green chemistry approach for the synthesis of silver nanoparticles is modest, amenable for large scale commercial production. Further the biologically synthesized silver nanoparticles are known for their potential antibacterial activity.
TL;DR: In this paper, the effect of different parameters such as precursor, power of pulsation, surfactant, and reaction time on the morphology of the products was investigated, and it was found that the as-obtained CeO2 nanoparticles exhibit a strong photoluminescence (PL) peak at 381 nm at room temperature that can be ascribed to the high level transition in the CeO 2 semiconductor.
Abstract: Uniform CeO2 nanoparticles were synthesized via a facile sonochemical reaction between ceric ammonium nitrate and ammonia. Nanoparticles were synthesized via a surfactant free reaction at room temperature in solvent of water. Products were characterized using X-ray diffraction, scanning electron microscopy, photoluminescence (PL) spectroscopy, and energy dispersive X-ray analysis. The effect of different parameters such as precursor, power of pulsation, surfactant and reaction time on the morphology of the products was investigated. It was found that the as-obtained CeO2 nanoparticles exhibit a strong PL peak at 381 nm at room temperature that can be ascribed to the high level transition in the CeO2 semiconductor. The photocatalytic behavior of CeO2 nanoparticles was evaluated using the degradation of a methyl orange aqueous solution under ultraviolet light irradiation. The results show that CeO2 nanoparticles are promising materials with excellent performance in photocatalytic applications.
TL;DR: In this paper, a magnetically recoverable Fe3O4/BiOCl nanocomposite photocatalysts were fabricated by a simple chemical coprecipitation method at room temperature.
Abstract: Magnetically recoverable Fe3O4/BiOCl nanocomposite photocatalysts were fabricated by a simple chemical coprecipitation method at room temperature. The amount of Fe3O4 incorporated into BiOCl was varied from 0 to 20 wt%. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, UV–Vis diffuse reflectance spectroscopy, and vibrating sample magnetometer. The obtained results show that the as-synthesized samples mainly contain both crystalline phases (Fe3O4 and BiOCl) and are composed of flower-like nanostructures. Compared to UV light-responsive BiOCl, all the nanocomposite photocatalysts show a strong light absorbance in the range of 250–800 nm, demonstrating that the Fe3O4/BiOCl nanocomposites can respond to visible as well as UV light. Moreover, visible light absorbance was increased with the increase in the Fe3O4 amount in the composite. The photocatalytic activity of nanocomposite photocatalysts was evaluated by the photodegradation of Rhodamine B (RhB) over the samples under visible light irradiation. The 10 wt% Fe3O4/BiOCl nanocomposite photocatalyst shows the highest photocatalytic efficiency among the samples. The Fe3O4/BiOCl nanocomposite photocatalyst was stable under visible light irradiation to efficiently degrade RhB molecules after five cycles and could be easily recovered with a magnet after each cycle.
TL;DR: In this article, the photocatalytic activity of the as-prepared α- and β-phase porous Bi2O3 microspheres have been tested by degradation of methylene orange under visible light.
Abstract: β- and α-phase porous Bi2O3 microspheres with an average size of around 4 μm had been synthesized by thermal treatment of Bi2O2CO3 microspheres at 350 and 400–500 °C respectively in an air atmosphere. The Bi2O2CO3 microspheres had been synthesized at a temperature of 180 °C by a hydrothermal process using Bi(NO3)3 as the bismuth source with the assist of citric acid. By combining the results of X-ray powder diffraction, transmission electron microscope, scanning electron microscopy, and UV–Visible absorption spectra, the structural, morphological and optical properties characterization of the products were performed. The photocatalytic activity of the as-prepared α- and β-phase porous Bi2O3 microspheres have been tested by degradation of methylene orange under visible light, indicating that porous β-Bi2O3 microspheres showed enhanced photocatalytic performance compared to P25 and α-Bi2O3 microspheres.
TL;DR: In this paper, NiO nanoparticles were synthesized and characterized by elemental analyses and Fourier-transformed infrared (FT-IR) spectroscopy, which confirmed the composition of products.
Abstract: Nickel(II) complex, Ni(Brsalph)(NO3) was synthesized and characterized by elemental analyses and Fourier-transformed infrared (FT-IR) spectroscopy. Heating of Ni(Brsalph)(NO3) at 550 °C for 3.5 h have resulted NiO nanoparticles. Fourier-transformed infrared spectrum confirmed the composition of products. The crystalline structures and morphology of NiO nanoparticles were studied by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy.
TL;DR: In this paper, a modified Stober procedure via a sonochemical method and the reaction between tetraethyl orthosilicate (TEOS), ethylenediamine (en) and methanol in water, in the attendance of Schiff-base ligand (H2Salen) as capping agent.
Abstract: Silica nanostructures were synthesized on the basis of modified Stober procedure via a sonochemical method and the reaction between tetraethyl orthosilicate (TEOS), ethylenediamine (en) and methanol in water, in the attendance of Schiff-base ligand (H2Salen) as capping agent. The effects of synthesis parameters such as: sonochemical irradiation time, sonochemical power and molar aspect ratio of Schiff-base ligand to TEOS were considered to achieve optimum situation. It was established that particle size, morphology and phase of the products could be affected by these parameters. The as synthesized silica nanostructures were characterized by X-ray powder diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and X-ray energy dispersive spectroscopy.
TL;DR: In this article, the electronic structure, stability, and tendency to exchange electron of neutral, anionic, and cationic small clusters were investigated by density functional theory calculations, and it was found that the most stable structures of Rh4, Rh3Cu and Rh2Cu2 have distorted tetrahedral shape.
Abstract: In this study, electronic structure, stability, and tendency to exchange electron of neutral, anionic, and cationic Rh
x
Cu4−x
(x = 0–4) small clusters were investigated by density functional theory calculations. For neutral small clusters, it was found that the most stable structures of Rh4, Rh3Cu and Rh2Cu2 have distorted tetrahedral shape while the most stable structures of RhCu3 and Cu4 have quasi-planer shape. Adding charges to the clusters, caused shapes of the most stable structures undergo variations. Stabilities of the neutral, anionic, and cationic clusters decrease linearly with increasing the copper content. In addition, calculated chemical harnesses indicated that the small cluster with 75 % copper content has the least chemical hardness. Interestingly, prevailing number of electronegative (Rh) and electropositive (Cu) atoms in the anionic and cationic clusters coincides with high dipole moment in these species that occur at 25 and 75 % copper respectively.
TL;DR: In this article, a highly efficient and visible light responsive nanocomposite photocatalyst Co3O4/WO3 was developed by dispersing p-type semiconductor Co 3O4 on the surface of n-type WO3.
Abstract: A highly efficient and visible light (λ ≥ 420 nm) responsive nanocomposite photocatalyst Co3O4/WO3 was developed by dispersing p-type semiconductor Co3O4 on the surface of n-type semiconductor WO3. The heterojunction Co3O4/WO3 demonstrated higher photocatalytic activity than WO3, Co3O4 and TiO2 nanoparticles for the complete decomposition of 2-propanol in gas phase and phenol in aqueous phase and evolution of CO2 under visible light irradiation. The highest photocatalytic efficiency of the composite Co3O4/WO3 was observed when calcined at 300 °C for 2 h with 4.91 mol% Co3O4/WO3. The enhanced photocatalytic efficiency of the heterojunction was discussed based on the unique relative energy band positions and profound absorption of visible light by the semiconductors.
TL;DR: In this paper, a simple hydrothermal method was used to synthesize hollow α-FeOOH urchin-like spheres and their thermal conversion was performed at 300-°C for 2-h in air.
Abstract: Hollow α-FeOOH urchin-like spheres were synthesized by a simple hydrothermal method at 160 °C for 12 h and their thermal conversion to hollow α-Fe2O3 urchin-like spheres was performed at 300 °C for 2 h in air. The results from X-ray diffraction and electron microscopy analyses reveal that hollow α-FeOOH urchin-like spheres were completely transformed to hollow α-Fe2O3 urchin-like spheres without a significant morphological change. Also, the effect of hydrothermal treatment temperature (170–200 °C for 12 h) on the phase structure and morphology of the final product was investigated. Pure α-FeOOH, the mixture of α-FeOOH and α-Fe2O3, and pure α-Fe2O3 with different morphologies were obtained at <180, 180–190 and 200 °C, respectively. The obtained materials can be used in the photodegradation of organic pollutants under visible light irradiation.
TL;DR: A facile sonoemulsion route using suitable non-ionic surfactant, polyethylene glycol with molecular weight of 8000 (PEG8000) was developed to synthesize long CuO nanorods with average diameter of 15-20nm and lengths up to 1.5 μm.
Abstract: A facile sonoemulsion route using suitable non-ionic surfactant, polyethylene glycol with molecular weight of 8000 (PEG8000) was developed to synthesize long CuO nanorods with average diameter of 15–20 nm and lengths up to 1.5 μm. The as-developed CuO nanorods were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, SAED and Raman spectroscopy. The Raman spectrum of as-synthesized nanorods was found to be red-shifted and broadened due to possible consequence of phonon confinement, electron–LO–phonon-coupling and internal compressive stresses. The dynamics of nanorod growth was elaborated in context of size aggregation effect fueled by ultra-sonication and steric hindrance effect imposed by PEG8000. The catalytic activity of CuO nanorods in thermal decomposition of potassium perchlorate was examined by thermogravimetric analysis technique. The CuO nanorods prepared by sonoemulsion route was found to be very effective in thermal decomposition of potassium perchlorate with significant reduction in thermal decomposition temperature.
TL;DR: In this article, the authors reported on the synthesis of Cu2S nanoparticles via an ultrasonic method by employing Na2SO3 as a reducing agent and characterized the morphology, structure, and composition of the obtained products by X-ray diffraction, energy dispersive Xray analysis, scanning electron microscope and photoluminescence spectroscopy.
Abstract: This study reports on the synthesis of Cu2S nanoparticles via an ultrasonic method by employing Na2SO3 as a reducing agent. Morphology, structure, and composition of the obtained products were characterized by X-ray diffraction, energy dispersive X-ray analysis, scanning electron microscope and photoluminescence spectroscopy. The effects of time and power of irradiation were studied.
TL;DR: In this paper, structural, electronic, and electrical responses of the H-capped (6,0) zigzag single-walled silicon carbide nanotube (SiCNT) were studied under the parallel and transverse electric fields with strengths 0.140 × 10−4 au by using density functional calculations.
Abstract: Structural, electronic, and electrical responses of the H-capped (6,0) zigzag single-walled silicon carbide nanotube (SiCNT) was studied under the parallel and transverse electric fields with strengths 0–140 × 10−4 au by using density functional calculations Analysis of the structural parameters indicates that resistance of the nanotube against the applied parallel electric field is more than resistance of the nanotube against the applied transverse electric field The dipole moments, atomic charge variations, and total energy of the (6,0) zigzag SiCNT show increases with any increase in the applied external electric field strengths The length, tip diameters, electronic spatial extent, and molecular volume of the nanotube do not change significantly with any increasing in the electric field strength The energy gap of the nanotube increases with any increases in the electric field strength and its reactivity is decreased Increase of the ionization potential, electron affinity, chemical potential, and HOMO and LOMO in the nanotube with increase of the applied external electric field strengths indicates that the properties of SiCNTs can be controlled by the proper external electric field for use in nano-electronic circuits
TL;DR: In this paper, a dumbbell-like BiVO4 and Ag/BiVO4 photocatalysts were synthesized by a simple hydrothermal method at 180 °C for 24 hours.
Abstract: Visible-light-driven dumbbell-like BiVO4 and Ag/BiVO4 photocatalysts has been successfully synthesized by a simple hydrothermal method at 180 °C for 24 h. The as-synthesized photocatalysts were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and UV–Vis absorption spectroscopy. The results obtained showed that ethylenediamine, citric acid, pH and hydrothermal reaction temperature have pronounced effects on the morphology of BiVO4. Transmission electron microscopy observation shows that the Ag nanoparticles are homogenously dispersed on the surface of the BiVO4 nanorods. Photocatalytic activities of the dumbbell-like BiVO4 and Ag-loaded BiVO4 photocatalysts were also evaluated by using methylene blue as a representative dye indicator under visible light irradiation. It is found that the photocatalytic performance of the as-synthesized BiVO4 is obviously improved with the incorporation of the Ag nanoparticles. Mechanism for the enhancement of the photocatalytic activity of the Ag/BiVO4 photocatalyst is also discussed.
TL;DR: In this article, solid-state molybdenum sulfide clusters with an octahedral metal framework, the superconducting Chevrel phases, are applied to catalysis, and the activated cluster exhibits catalytic activity for the ring-opening of tetrahydrofuran, yielding butyraldehyde.
Abstract: Solid-state molybdenum sulfide clusters with an octahedral metal framework, the superconducting Chevrel phases, are applied to catalysis. The cluster of copper salt, Cu
x
Mo6S8 (x = 2.94), stored in air is treated in a hydrogen stream above 300 °C. The activated cluster exhibits catalytic activity for the ring-opening of tetrahydrofuran, yielding butyraldehyde. Cyclic ethers such as trimethylene oxide and tetrahydropyran are also converted to the corresponding aldehydes. The cluster contains nonstoichiometric defects of sulfur atoms. Oxygen atoms are incorporated at the sulfur-deficient sites upon storage in air, but they are removed from the sites by the activation in a hydrogen stream. The resulting coordinatively unsaturated molybdenum atoms are catalytically active for the ring-opening reaction. The molybdenum atom in an intermediate oxidation state around 2+ is moderately coordinated by the oxygen of tetrahydrofuran and favorably releases the produced aldehyde. The neutral cluster Mo6S8, which has such sulfur-deficient sites, also catalyzes the reaction.
TL;DR: In this paper, nano-sized magnesium aluminate powders were successfully synthesized via microwave process based on the reaction between Mg (NO3)2·6H2O and Al (NO 3)3·9H 2O in distilled water, at various conditions.
Abstract: In the present study, Nano-sized magnesium aluminate powders were successfully synthesized via microwave process based on the reaction between Mg (NO3)2·6H2O and Al (NO3)3·9H2O in distilled water, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, photoluminescence (PL) spectroscopy, and EDAX analysis. The effects of different parameters such as reaction time and microwave power on the morphology, particle size, and PL properties of the product were studied by SEM images and the PL.
TL;DR: In this article, the authors investigated the functionalization of C60 fullerene with one to six carbene (CH2) molecule(s) using density functional theory and found that the reaction is regioselective so that a CH2 molecule prefers to be adsorbed atop a C-C bond which is shared between two hexagonal rings of the C60, releasing energy of −3.95 eV.
Abstract: Chemical functionalization of C60 fullerene with one to six carbene (CH2) molecule(s) has been investigated using density functional theory. We have found that the reaction is regioselective so that a CH2 molecule prefers to be adsorbed atop a C–C bond which is shared between two hexagonal rings of the C60, releasing energy of −3.95 eV. Singly occupied molecular orbital (SOMO) of the CH2 interacts with LUMO of the C60 via a [2 + 1] cycloaddition reaction. Energy of the reaction and work function of the system are decreased by increasing the number of adsorbed CH2 molecules. The HOMO/LUMO energy gap of C60 is slightly changed and the electron emission from its surface is facilitated upon the functionalization.
TL;DR: In this paper, the adsorption energy of phenol on the external surface of H-capped pristine, Ga-doped, and Pd-decorated (6,0) zigzag boron phosphide nanotubes was studied by using density functional theory (DFT) calculations.
Abstract: Phenol adsorption on the external surface of H-capped pristine, Ga-doped, and Pd-decorated (6,0) zigzag boron phosphide nanotubes (BPNTs) was studied by using density functional theory (DFT) calculations. The results indicate that the hydroxyl group of phenol prefers to attach to the Ga and Pd sites and thus the Ga-doped and Pd-decorated (6,0) can be used for removing phenol. The calculated adsorption energy of phenol on the Ga-doped and Pd-decorated (6,0) BPNTs are −0.724 and −420 eV, respectively and about 0.28 and 0.27 electrons are transferred from phenol to the nanotubes. In addition, the value for the fractional number of electrons transferred is negative, indicating that phenol act as an electron donor. Frontier molecular orbital theory (FMO) and structural analyses show that the high polar surface bonds and large bond lengths of the Ga-doped and Pd-decorated (6,0) BPNT surfaces increase the adsorption of phenol on the nanotube models. This study can be useful in removing phenol and development of many catalytic processes for formation of a variety of useful compounds.
TL;DR: In this article, a well-segregated bismuth sulfide (Bi2S3) nanorods with a high order of crystallinity have been successfully prepared from Bismuth(III) monosalicylate [BiO(C7H5O3)] by a simple hydrothermal reaction in H2O at 180°C.
Abstract: Well-segregated bismuth sulfide (Bi2S3) nanorods with a high order of crystallinity have been successfully prepared from bismuth(III) monosalicylate [BiO(C7H5O3)] by a simple hydrothermal reaction in H2O at 180 °C. Bismuth(III) monosalicylate and thioglycolic acid act as the starting materials. The products were characterized by powder X-ray diffraction, Ultraviolet–Visible (UV–Vis) spectroscopy, transmission electron microscopy photoluminescence spectroscopy, and Fourier transform infrared spectra. The powder X-ray diffraction pattern shows the product belongs to the orthorhombic Bi2S3 phase. Their UV–Vis spectrum shows the absorbance at 328 nm, with its direct energy band gap of 2.6 eV. Bismuth salicylate, which is known to be a complex, may play a critical role as a precursor and a template for the growth of linear bismuth sulfide nanorods. Finally the influences of the reaction conditions are discussed and a possible mechanism for the formation of Bi2S3 nanorods is proposed.
TL;DR: In this article, the electronic transitions of three hydrogen-bonded ethanol-water complexes were investigated using the time-dependent density functional theory method, and it was shown that the different electronic transition types should be the reasons for the tiny redshift of the S1-state electronic energy for Dimer-I and the large blueshifts for the Trimer compared with that of the ethanol monomer.
Abstract: In this work, time-dependent density functional theory method was used to study the electronic transitions of hydrogen-bonded ethanol–water complexes Dimer-I, Dimer-II and Trimer. The intermolecular hydrogen bonds H1···O1 and O···H2 were demonstrated by the optimized geometric structures of the three hydrogen-bonded ethanol–water complexes. It is demonstrated that the S1-state electronic transitions for ethanol monomer and the hydrogen-bonded complex Dimer-I (through HB-I) should be of LE nature on the ethanol molecule, while those of complexes Dimer-II and Trimer should be of CT character from the hydrogen-bonded water molecule (through HB-II) to the ethanol moiety. The different electronic transition types should be the reasons for the tiny redshift of the S1-state electronic energy for Dimer-I and the large blueshifts for Dimer-II and the Trimer compared with that of the ethanol monomer.
TL;DR: Porous peanut-like TiO2/BiVO4 composite nanostructures were synthesized via a template-free hydrothermal process with bismuth nitrate, ammonium metavanadate and anatase TiO 2 as raw materials.
Abstract: Porous peanut-like TiO2/BiVO4 composite nanostructures were synthesized via a template-free hydrothermal process with bismuth nitrate, ammonium metavanadate and anatase TiO2 as raw materials. The crystal structures, morphologies, and optical properties of the as-prepared samples were characterized by X-ray powder diffraction, transmission electron microscope, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–visible absorption spectra. Simulated sun-light induced photocatalytic degradation of Rhodamine B by porous peanut-like TiO2/BiVO4 nanostructures in the absence and presence of H2O2 has been investigated, and the results show these porous composite nanostructures with higher photocatalytic activity than pure BiVO4 and anatase TiO2. When TiO2/BiVO4 heterostructures were used as the photocatalysts under simulated sun-light irradiation, BiVO4 could act as a sensitizer to absorb the visible light. Meanwhile, coupling different band-gap semiconductors of TiO2 and BiVO4, the compound facilitate separation of the photogenerated carriers under the internal field induced by the different electronic band structures of semiconductors.