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Abstract This paper investigates the reaction mechanism in mechanochemical synthesis of Cu 2-x Se by vibrational milling of (Cu+Se) powder mixture. The effects of milling time, milling mode, ball-to-powder weight ratio (BPWR), and Cu/Se molar ratio in the starting composition on the phase assemblage of the products are investigated. It is found that, the synthesis of Cu 2-x Se is improved by increasing milling time, BPWR, and Cu/Se ratio. For a fixed total milling time, continuous milling is better than intermittent milling to facilitate the formation of Cu 2-x Se. By continuous milling for 20 min with BPWR = 6 and Cu/Se = 2, almost single-phase β-Cu 2-x Se is produced except for minor un-reacted Cu. A diffusion-controlled reaction mechanism is proposed for the mechanochemical synthesis of Cu 2-x Se, where intermediate phases such as CuSe and Cu 3 Se 2 with lower Cu/Se ratios are produced at first and then gradually converted into Cu 2-x Se with the diffusion of Cu atoms. [ABSTRACT FROM AUTHOR]

Abstract In the present paper, a novel dye of 4-methyl-5-(4-acetylphenyldiazenyl)thiazol-2-amine ( L ) and its corresponding copper complexes are synthesized and characterized using different techniques including elemental analysis, thermal analysis, 1H NMR, Mass, and FT-IR spectra. The thermal behavior of L and its complexes is carried out and discussed using thermogravimetric analysis, and it observed that the type of copper substituent affects the thermal decomposition of complexes. Homogenous thin films of L and its complexes are successfully grown onto quartz substrates using spin coating technique. Optical features and spectral phenomena of the thin films are studied using spectrophotometric measurements of absorbance, transmittance and reflectance. The optical constants such as refractive index, extinction coefficient, optical conductivity and energy loss functions of the thin films of L and its complexes are calculated. The refractive index curves for all films show a normal dispersion behavior in the non-absorbing region of spectra, from which the dispersion parameters can be calculated using Wemple-DiDomenico model. The type of optical transition bands shows indirect allowed. The values of the optical energy gap are calculated in the range from 2.13 to 2.33 eV, depending on the nature of Cu(II) substituent. Indeed, the present results show that the complexes as organic semiconductors acquired good characterizations better than metal free ligand ( L ) such as more thermal stability, reducing in the optical band gap and increasing in the absorption coefficient that refers to light harvesting capacity. Graphical Abstract Unlabelled Image Highlights • A novel dye of aminothiazole and its Cu(II) complexes have been synthesized and characterized. • The thin films of these complexes have been grown by spin coating technique. • The optical constants and dispersion parameters of the complexes have been studied. • Substitution patterns of C(II) salts influenced the optical and thermal properties. • The optical band gaps for the complexes vary from 2.13 to 2.33 eV depending on the nature of substituent. [ABSTRACT FROM AUTHOR]

Abstract This paper reports the synthesis of 5-(5-methyl-benzofuran-3-ylmethyl)-3H- [1, 3, 4] oxadiazole-2-thione (5MBOT) and characterization by FT-IR, FT-Raman, 1H NMR, 13C NMR and UV spectral studies. The density functional theory (DFT) calculations have been executed for the 5MBOT using B3LYP/6-31++G (d, p) basis set. The fundamental modes of the vibrations were designated by the potential energy distribution (PED), and the computed and experimental values support each other. The 1H NMR and 13C NMR chemical shifts of 5MBOT were estimated by gauge-including atomic orbitals (GIAO) method and compared with the experimental chemical shifts. The UV–Vis method used to study the visible absorption maxima (λ max ) by using Time-Dependent DFT. Further, the Mulliken population analysis (MPA), natural population analysis (NPA) charges, thermodynamic properties at different temperatures were presented. The calculated HOMO and LUMO energies show that charge transfer within the molecule. The natural bonds orbital (NBO) also computed. Optoelectronic properties have been carried out by combination of DFT calculations and molecular dynamics (MD) simulations, in order to assess the potential of this structure for applications in organic electronics. Further, the study encompassed calculations of reorganization energies for holes and electrons and charge transfer rates. DFT calculations have been also used in order to identify locations possibly sensitive towards the autoxidation mechanism, which correlates between bond dissociation energy for hydrogen abstraction and the mechanism. The MD simulations have been used to understand interaction of 5MBOT with water molecules. Molecular docking studies reveals the antifungal activity of 5MBOT may be due to hydrogen bonding and hydrophobic interactions with different antifungal proteins. Graphical Abstract Unlabelled Image Highlights • 5MBOT was prepared and characterized by FT-IR, FT-Raman, 1HNMR, 13CNMR and UV spectral studies. • DFT calculations, optoelectronic properties and molecular dynamics simulations have been studied. • Experimental and theoretical spectral analyses were matched well. • The title molecule exhibited good chemical stability and hardness. • Intramolecular interactions were estimated by NBO analysis. • Molecular docking analysis show anti-microbial activity due to hydrogen bonding and hydrophobic interactions with proteins. [ABSTRACT FROM AUTHOR]

In this paper we report synthesis of a heterogeneous catalyst for the first time, by anchoring a zinc complex to mesoporous silica MCM-41. The structure of functionalized MCM-41 was characterized by FT-IR, XRD, SEM, TEM, TGA, ICP, EDA and BET techniques. Functionalized MCM-41 (MCM-41@AMPD@Zn) exhibits excellent catalytic activity in the oxidation of various sulfides into sulfoxides in the presence of hydrogen peroxide (H 2 O 2 ) as oxidant, oxidative coupling of thiols into disulfides at room temperature and the synthesis of 5-substituted tetrazoles from sodium acid (NaN 3 ). The heterogeneous catalyst showed good recovery and recyclability up to 8 consecutive cycles without significant loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • This article provides a review of the preparation method of Ag nanopaste. • The effect of adding different type of reinforcing groups in Ag paste are introduced. • The recent applications of low temperature sintered Ag joint are summarized. Abstract To meet the requirement of bonding power chips in microelectronic packaging, low temperature sintering silver (Ag) nanopaste appears to be the most interesting choice in several new attachment technologies. This opportunity is mainly attributed to its high electrical and thermal conductivities of the sintered joint, and its low elastic modulus and process temperature. Over the past decade, in order to improve the mechanical properties, electrical conductivity and thermal conductivity of sintered Ag nanopaste, the formulas for preparing Ag nanopaste were improved, and other materials also have been added into it to make a reinforced matrix. In this review, the material characteristics of Ag nanopaste under low temperature sintering are elucidated, including the progress in the synthesis of Ag nanoparticles, the preparation methods of Ag nanopaste and bonding performance of low temperature sintered Ag nanopaste. The effects of adding different types of reinforcing groups into Ag paste on the bonding properties of sintered Ag joints are discussed, such as carbon reinforced matrix, metal reinforced matrix and other reinforced materials. The recent applications of low temperature sintered Ag joints in power chips are summarized. In addition, the feasibility of preparing Ag nanopaste while adding additional enhancers will be discussed at the end of the paper. [ABSTRACT FROM AUTHOR]

Abstract The investigation reports in Fe 2 W 3 O 12 are few due to the synthesis difficulty of pure phase Fe 2 W 3 O 12. In the paper, rapid synthesis of pure phase Fe 2 W 3 O 12 is developed using solid state sintering method with Fe 2 O 3 and WO 3 as raw materials and the addition of MoO 3. The intermediate phase Fe 2 WO 6 is easy to form by sintering Fe 2 O 3 and WO 3 with the content of addition MoO 3 less than 3 mol%. Only after the content of addition MoO 3 reaches 5 mol%, the Fe 2 W 3 O 12 could form easily, even the temperature lower to 1000 °C. It is considered that addition MoO 3 plays as a catalyst-stabilizer in the formation of Fe 2 W 3 O 12. The as-synthesized Fe 2 W 3 O 12 shows low thermal expansion (1.35 × 10−6 °C−1) from 445° to 600 °C. [ABSTRACT FROM AUTHOR]

Abstract The present paper demonstrates an easy and scalable mechanochemical synthesis of ternary sulfide Cu 2 SnS 3 (CTS) as a promising solar cell absorber. For the synthesis, pre-milled nanoparticles of CuS and SnS were used. The pure CTS phase was readily obtained after 60 min of milling in a laboratory planetary ball mill and 240 min in an industrial eccentric vibration industrial mill, respectively. The reaction progress of laboratory scale synthesis was studied by the quantitative Rietveld analysis. The reaction speed reaches its maximum at 4.6 min and the reaction is completed at approximately 60 min, according to the fitted data. The products of the syntheses were further characterized by X-ray powder diffractometry, Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–Vis spectroscopy. The results revealed formation of near-stoichiometric CTS nanoparticles with tetragonal I -42 m symmetry. An average crystallites size of approximately 10–15 nm was determined for CTS phase. The SEM images support quintessential polydisperse character of the powders obtained by ball-milling approach. The materials seem to be suitable for photovoltaic applications with the band-gap energies of approximately 1.16–1.19 eV. Highlights • Cu 2 SnS 3 (CTS) is considered as one of the possible solar cell absorber materials. • CTS nanocrystals may be synthesized via eco-friendly unassuming mechanochemical reaction. • Quintessential polydisperse CTS nanocrystal system is obtained by ball-milling method. • The band-gap energies of 1.16–1.19 eV calculated for CTS nanocrystals are suitable for photovoltaic applications. [ABSTRACT FROM AUTHOR]

Dicalcium silicate finds applications in different fields (cement, bio-ceramics, refractories). In the case of Portland cement, its interest is its lower sintering temperature compared to tricalcium silicate and therefore an interesting compound for low CO 2 cements. Dicalcium silicate goes through different polymorphic forms, namely α, α' H , α' L , β and γ, as the temperature decreases. In theory, only the γ-phase is stable at room temperature. In a polycrystalline material, the different polymorphs can co-exist depending on several factors (sintering conditions, presence of impurities, grain size) and the interpretations given in the literature are sometimes contradictory. For cement applications, only the α, α' or β polymorphs react with water to give hydrates while γ does not. Therefore, this paper focuses specifically on the effect of grain size on the β to γ transformation. We also propose that the transformation is semi-reconstructive and not martensitic as suggested by some authors. [ABSTRACT FROM AUTHOR]

Mercury contamination in aquatic systems has been an issue to the natural ecosystem and human health. Environmental models have become a valuable decision-making tool and play a significant role in mercury pollution control and management. This paper gives an overview of currently available models for simulating mercury transport and fate in aquatic systems. The mercury transformation mechanisms included in these models were identified, as well as data limitations in the models' application. Future advances in understanding mercury transport, cycling, and biogeochemistry in both water column and sediment will improve the robustness of current modeling applications. Moreover, additional field data are critically needed to better predict the concentrations of multi-phase mercury species in various aquatic systems, including measurements in the water column, benthic sediments, and organisms. Field data are also crucial for model calibration and validation. Without this information it will not be possible to adequately understand the environmental factors controlling mercury fate in aquatic systems. The insufficient quantity of adequate measurements and the unsatisfactory accuracy of mercury models are, in numerous cases, supplemented by mass balances since they diminish the unreliability of models. Mercury science evolves gradually with the advancement of science and technology, which requires that mathematical modeling of mercury transport and transformation should be consistently updated. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Synthesis of hierarchical beta without OSDAs, PDAs, or mesoporous templates. • Hierarchical beta zeolites with enlarged mesopores. • Considerably improved catalytic performance for the conversion of bulky molecules. Abstract This paper reports a straightforward approach to synthesizing hierarchical beta zeolites by exposing microporous zeolites to hydrothermal conditions amenable for beta crystallization, which simultaneously creates hierarchical pore structure while maintaining crystallinity and framework integrity without the use of organic structure-directing agents, pore-directing agents, or mesoporous templates. The obtained hierarchical beta zeolites possess enlarged mesopores and exhibit improved catalytic performance for the conversion of bulky molecules in the liquid-phase conversion of benzyl alcohol with mesitylene. A sequential hierarchical structure formation and recrystallization mechanism is proposed to elucidate the creation of mesopores in beta zeolites with excellent preservation of acidity and microporosity. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of 2-(4-hydroxyphenyl)ethyl and 2-(4-nitrophenyl)ethyl substituted benzimidazolium salts. The benzimidazolium salts were synthesized by N-substituted benzimidazolium and aryl halides. The 2-(4-hydroxyphenyl)ethyl and 2-(4-nitrophenyl)ethyl substituted benzimidazolium salts were characterized by using 1 H NMR, 13 C NMR, FT-IR spectroscopy and elemental analysis techniques. Molecular and crystal structure of the complex 2d and 3d were obtained by single-crystal X-ray diffraction method. Additionally, The enzyme inhibition activities of the benzimidazolium salts were investigated. These 2-(4-hydroxyphenyl)ethyl and 2-(4-nitrophenyl)ethyl substituted benzimidazolium salts (1, 2a-g, and 3a-f) showed good inhibitory action against acetylcholinesterase (AChE), and human (h) carbonic anhydrase (CA) isoforms I, and II. Ki values for AChE were in range of 5.97 ± 0.56–23.15 ± 3.98 nM. On the other hand, the hCA I, and II isoenzymes were effectively inhibited by these compounds, with K i values in the range of 17.33 ± 4.55–99.23 ± 44.91 nM for hCA I, and 33.98 ± 3.43–113.23 ± 39.31 nM for hCA II, respectively. [ABSTRACT FROM AUTHOR]

In this research paper we report synthesis of two planar ligands, namely 1,3-dimethyl-5-(4ʹ/3ʹ-pyridylazo)-6-aminouracil: HL1 (1 ) for 4ʹ-pyridyazo- and HL2 ( 2 ) for 3ʹ-pyridyazo-group and, moreover, their nickel (II) square planar complexes ([Ni II (L1) 2 ] ( 3 ) and ([Ni II (L2) 2 ] ( 4 )). The report is also included solid and solution state structure of the compounds and study of noncovalent stacking interactions. Crystal structures of the ligands, 1 and 2 are monoclinic with alike space group P 2 1 / c and the complex 3 is also monoclinic with space group C 2/ c . The molecular electrostatic potential (MEP) analysis shows that the ligands possess both π-basic and π-acid character in the same framework over the center of the pyridine and the pyrimidine rings, respectively, favoring electrostatically enhanced π-π stacking interaction among the molecular units. Upon complexation, π-acidity of the pyrimidine ring increases, and the complex 3 exhibits lone pair (lp)-π stacking interaction involving lone pair of the pyridine N-atom and π-acid pyrimidine plane. The study evidences that the ligands exist in azo-enamine-keto tautomer in solid and hydrazone-imine-keto in solution state and get coordinated with nickel (II) via azo- N and uracil-6- N H , to form a distorted square planar complex. Electronic absorption bands/energies obtained from experimental and theoretical (TDDFT) study are indeed alike, giving reliability to the level of theory and the absorption band assignments. Moreover, the synthesized compounds containing uracil and pyridine fragments exhibit π-π/lp-π interactions with considerable energy for stabilization of their assemblies in the solid state. [ABSTRACT FROM AUTHOR]

Abstract Large-scale fabrication, sensitivity and selectivity are important considerations for the practical applications of metal-oxide nanowire (NW) gas sensors fabricated by thermal evaporation. This paper reports the effect of the distance between the source and the microelectronic chips on the gas-sensing properties of ZnO and Zn 2 SnO 4 NW sensors fabricated by on-chip growth via thermal evaporation. Results indicate that the placement of the microelectrode chips in the range of 2–6 cm results in a similar response for ZnO NW sensors but an order of magnitude difference in response for Zn 2 SnO 4 NW sensors as measured at 10 ppm NO 2. The response of Zn 2 SnO 4 NW sensors is significantly higher than that of ZnO NW sensors. Similar to that of ZnO NW sensors, the NW–NW junction density of Zn 2 SnO 4 NW sensors strongly affects their NO 2 gas-sensing performance. The selectivity of Zn 2 SnO 4 NW sensors is much better than that of ZnO NW sensors under testing with interference gases, such as CO, H 2 , H 2 S and NH 3. Highlights • The gas-sensing performance of ZnO and Zn 2 SnO 4 nanowires were systematically compared. • The distance between source and chip strongly affected on gas response of Zn 2 SnO 4 nanowires. • The gas response of Zn 2 SnO 4 nanowires were strongly affected by the density of the nanowires. • The Zn 2 SnO 4 nanowire sensors exhibited a better selectivity to NO 2 gas as compared to ZnO nanowire sensors. [ABSTRACT FROM AUTHOR]

In this paper, Mg 0.5 Ti 2 (PO 4 ) 3 with the NASICON-type structure was evaluated for the first time as a possible host structure of Co 2+ for obtaining an inorganic pigment with violet color. The powders were synthesized by solution combustion synthesis using glycine (G) and urea (U) as fuels and different oxidizer-to-fuel (O/F) ratios when ammonium nitrate was used as an extra-oxidant. However, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) technics showed that the as-prepared powders were amorphous, which is due possibly by the effect of fire retardant of the diammonium hydrogen phosphate used as a source of phosphate during the synthesis. The calcination temperature for the as-prepared powders was established using Differential scanning calorimetry and Thermogravimetry (DSC/TGA), which showed crystallization temperatures less than 900 °C. Therefore, the powders were calcined at 900 °C for 3 h and the formation of the NASICON structure was confirmed using XRD and FTIR. The morphology was evaluated using Scanning electron microscopy (SEM) and the micrographs shown aggregated particles with irregular shapes. The optical properties of the inorganic pigments were studied using diffuse reflectance ultraviolet-visible-near infrared (Uv–Vis–NIR) spectroscopy, which showed that the band gap of the samples was E g,indirect  = 3.13 eV for NASICON Mg 0.5 Ti 2 (PO 4 ) 3 and E g,indirect  = 3.17 eV for NASICON Mg 0.45 Co 0.05 Ti 2 (PO 4 ) 3 . For this reason, the band gap of the system does not depend on dopping with Co 2+ for the concentration used. Thus, the mechanism of color is due to electronic transitions in DMSO-d6 orbitals with octahedral coordination for Co 2+ in NASICON Mg 0.45 Co 0.05 Ti 2 (PO 4 ) 3 . TSR (total solar reflectance) between 700 nm and 1800 nm were 95.94% for NASICON Mg 0.5 Ti 2 (PO 4 ) 3 and 81.41% for NASICON Mg 0.45 Co 0.05 Ti 2 (PO 4 ) 3 . These results show that the pigments could be potential candidates for the application as cold pigments. [ABSTRACT FROM AUTHOR]

Abstract An aluminosilicate precursor, such as metakaolin, can be transformed into a cement-like geopolymer binder via a phosphate activation approach. This paper identifies the effect of the addition of aluminum species into the phosphate activating solution on the formation of such geopolymers, from the fresh to the hardened state. Activating solutions with Al/P molar ratios of 0, 0.1, and 0.3 were prepared by blending monoaluminum phosphate (MAP) and orthophosphoric acid (OPA). The rheological properties, fluidity, and setting times of the fresh geopolymer pastes and the compressive strength of the hardened geopolymer matrices were studied. Liquid-state 27Al and 31P nuclear magnetic resonance (NMR) measurements for the chemical environments of Al and P, and spectroscopic, thermal, and microscopic analyses revealed that the soluble aluminum in the phosphate activating solution played an important role during the geopolymerization process. Seeding of aluminum species through inclusion in the activating solution allowed a rapid sol/gel transition that improved the rheological properties and setting time of the fresh geopolymer pastes at ambient temperature. However, although the increased concentration of aluminum phosphate oligomers promoted by the soluble aluminum addition contributed to the formation of a compact matrix with high early strength, it hinders the ongoing reaction of metakaolin in the later period, which has a detrimental influence on ongoing strength development beyond 7 days of curing. [ABSTRACT FROM AUTHOR]

A series of white light emitting Dy 3+ doped lead borate (DY) and lead alumino borate (DYA) glasses have been prepared by melt quench technique and are explored by XRD, FTIR, optical absorptions, fluorescence and density measurements. In this paper an effort has been made to compare the structural changes and luminescence efficiencies of prepared glasses by changing dysprosium oxide content and glass network environment by adding aluminium oxide. The XRD profile of all the glasses confirms their amorphous nature and FTIR study shows the presence of BO 3 and BO 4 groups. Incorporation of Al 2 O 3 in the glass system is responsible for a strong effect on luminescence of the present glass system. There is a strong correlation between Dy 3+ ions concentration and the host glass composition on the energy transfer mechanism. The decay curves deviate gradually from single exponential function at lower concentrations to non-exponential behavior at higher concentrations. The Inokutie Hirayama (IH) model for S= 6 fits well the non-exponential decay curves that indicate dipole-dipole type energy transfer between donor and acceptor ions. The calculated chromaticity coordinates lie in the white region of CIE 1931 chromaticity diagram and are in excellent proximity with the standard equal energy white illuminant (0.333, 0.333). Furthermore, the calculated correlated color temperature and the yellow to blue (Y/B) ratio of the synthesized photonic glasses may offer the possibility of tuning the white light by varying concentration and host environment which could be useful for various photonic based device applications. [ABSTRACT FROM AUTHOR]

Abstract Carbon capture and storage (CCS) community has been struggling over the past few decades to demonstrate the economic feasibility of CO 2 sequestration. Nevertheless, in practice, it has only proven feasible under conditions with a market for the recovered CO 2 , such as in the beverage industry or enhanced oil/gas recovery. The research community and industry are progressively converging to a conclusion that CO 2 sequestration has severe limitations for the value proposition. Alternatively, creating diverse demand markets and revenue streams for the recovered almost-pure CO 2 may prevail over CO 2 sequestration option and improve the economic feasibility of this climate change mitigation approach. As such, research in the carbon capture and management field is seen to be shifting towards CO 2 utilization, directly and indirectly, in energy and chemical industries. In this paper, we have critically reviewed the literature on carbon capture, conversion, and utilization routes and assessed the progress in the research and developments in this direction. Both physical and chemical CO 2 utilization pathways are studied and the principles of key routes are identified. The literature is also probed in addressing the process integration scenarios and the performance assessment benchmarks. [ABSTRACT FROM AUTHOR]

Carbon dots are optically unique materials for sensing applications that can be prepared from various raw natural materials. In this work, highly fluorescent carbon dots were synthesized from enokitake mushroom via a one-step hydrothermal method in the presence of diluted sulfuric acid. The spherical carbon dots, with an average diameter of 4 nm, exhibited blue photoluminescence under UV illumination and a quantum yield of 11%, increasing to 39% upon passivation with tetraethylenepentamine. We employed both photoluminescence and light absorption properties of carbon dots for Cr 6+ and volatile organic compound (VOC) sensing. Their fluorescence emission was selectively quenched by Cr 6+ with a limit of detection of 0.73 µM. A fluorescent colorimetric paper-based device was fabricated and demonstrated to determine Cr 6+ at concentrations as low as 10 µM. The carbon dots were also shown to have sensitivity and selectivity towards VOCs when integrated into an optical electronic nose. They were then used successfully to determine alcohol contents in aqueous solutions and ethanol concentration in a real spirit sample. They were further tested as a fingerprint detection agent and fluorophore for the manufacture of fluorescent plastics. Our results demonstrated that enokitake mushroom can be used to produce multi-faceted carbon dots with diverse applications. [ABSTRACT FROM AUTHOR]

The Si distribution strongly influences the surface acidity and catalytic performance of SAPO-11 molecular sieve. In this paper, SAPO-11 with different Si distributions and surface acidities were prepared by regulating hydrogel synthesis temperature and a possible mechanism for the regulating effect was discussed. The higher hydrogel synthesis temperature inhibited the formation of layered intermediates in the initial gel, but accelerated the incorporation of Si into the framework and growth of SAPO-11 crystal in the preliminary crystallization. It could increase the concentration of Si islands, generating less Brønsted acid sites on the surface of final products. In contrast, more isolated Si species in framework of SAPO-11 formed when the hydrogel was prepared at a lower temperature, creating more Brønsted acid sites. Besides, the concentration of Brønsted acid sites on the external surface was maximized in the sample prepared at 20 °C of the hydrogel synthesis temperature. This work provides a simple route to regulate the Si distribution and surface acidity of SAPO-11 molecular sieve without extra agents. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of a novel magnetically recoverable catalyst by immobilization of a copper(II)-5-phenyl-1 H -tetrazole complex on the surface of Fe 3 O 4 @SiO 2 nanoparticles [Fe 3 O 4 @SiO 2 -Tet-Cu(II)]. The catalyst was fully characterized by using different techniques such as XRD, FE-SEM, EDS, TEM, FT-IR, VSM and TG-DTA. The [Fe 3 O 4 @SiO 2 -Tet-Cu(II)] was used for the reduction of 4-nitrophenol (4-NP), 2,4-dinitrophenylhydrazine (2,4-DNPH), methylene blue (MB) and Nigrosin (NS) in aqueous medium at room temperature by using NaBH 4 as a reducing agent. Catalytic performance studies revealed that [Fe 3 O 4 @SiO 2 -Tet-Cu(II)] catalyst have excellent activity towards reduction reactions under mild conditions. The reaction process was monitored by using UV–Vis spectroscopy. Easy preparation, high catalytic activity, short time of reaction, and simple recovery from the reaction mixture are the specific properties of this efficient catalytic system. The catalyst can be easily recovered by using an external magnet and reused for at least five cycles without significant decrease in performance. These findings revealed that [Fe 3 O 4 @SiO 2 -Tet-Cu(II)] is a good catalyst and it can be used for different catalytic systems as a catalyst. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have received special attention in recent years as a result of their attractive and unique properties such as structure flexibility, high surface area, tunable pore size and functionalizable organic linkers and metal centres which have led to vast array of promising applications. Their properties can be improved to further enhance their performance by functionalization of the organic linkers, postsyntheic modification, and doping of nanomaterials into their frameworks. In this review, some recent synthetic methods for the preparation of MOFs are discussed, especially those that are applicable to CO 2 adsorption. The second part of this paper discusses the applications of MOFs as heterogeneous catalyst for various CO 2 conversion processes, with a view to address some of the challenges faced by the current technology of CO 2 conversion which tend to be very energy intensive processes with high level of waste emission and cost. The current state of MOF commercialization for niche markets is also discussed. [ABSTRACT FROM AUTHOR]

In this paper all efforts have been devoted to develop stabilized tannic acid-SO 3 H on Fe 3 O 4 @SiO 2 nanoparticles as the new magnetically and eco-friendly nanocatalyst. This nanocatalyst was identified using different techniques such as fourier transform infrared (FT-IR), Powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDXS) and thermogravimetric analysis (TGA). Catalytic performance of the catalyst in cyclocondensation reaction of anthranilamide with different aldehydes under the friendly environmentally reaction condition led to formation corresponding 2,3-dihydro-4(1H)-quinazolinones compounds in excellent yields. The catalyst could be easily recovered by an external magnet and reused 4 times without significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

In China, the most commonly used method for the synthesis of ibuprofen is aryl-1,2–translocation rearrangement, which comprises several main processes: the Friedel-hydrolysis reaction, ketal reaction and so on. There are some problems in the process of industrial production. The temperature control of the Friedel-hydrolysis reaction is a problem because excessive temperatures will lead to the occurrence of side reactions, and low temperatures will lead to the crystallization of raw reaction materials. The reaction time of the ketal reaction is up to 24 h, which limits the productive capacity of ibuprofen. Otherwise, the emissions of the ibuprofen synthesis processes are more than 5000 m 3 /h of waste gas with VOC contents of over 1000 mg/m 3 and highly concentrated organic wastewater, with a COD up to 20,000 mg/L. Therefore, process intensification and waste minimization of the ibuprofen synthesis process is described in this paper. A new reactor is designed for the Friedel-hydrolysis reaction. The reaction temperature can be precisely controlled at 13–15 °C, which effectively inhibits the occurrence of side reactions. The industrial applications showed that the ketal reaction time is reduced from 24 h to less than 8 h. The VOC content is reduced to less than 100 mg/m 3 , and the COD value is reduced to 150 mg/L in the improved processes, which meet national emissions standards. [ABSTRACT FROM AUTHOR]

A substituted spirooxazine was synthesized and characterized by 1 H, 13 C NMR, and HR-MS spectroscopic techniques. The open form of the spirooxazine derivative was evaluated for the detection of Fe 3+ ions. The colorimetric evaluation revealed that the receptor 1 is highly selective and sensitive towards Fe 3+ detection and displayed a turn-off fluorescence response with ferric ions through aggregation induced phenomena. No competitive behavior was observed for detection of Fe 3+ ions by the receptor in the presence of different metal ions. The paper based strips for 1 displayed an excellent selectivity and sensitivity (38 nm, 2.12 ppb) for Fe 3+ ions. We believe that the receptor 1 could be used as a Fe 3+ sensor on field detection tool kit. The B3LYP and B3LYP-D3BJ based methods were used to further investigate the stability of the different stereoisomers of merocyanine in order to find a possible mode of binding, while TD-DFT methods were used to study the UV-Visible and fluorescence spectra observed for the receptor. [ABSTRACT FROM AUTHOR]

This paper reports the encapsulation of antioxidant molecule Quercetin on PEG-diamine coated nanoparticles (NPs) by aqueous synthesis method to improve itʼs poor water solubility and stability. Two types of PEGylated NPs (PEGylated CdSe and PEGylated CdSe/CdS) have been used to conjugate Quercetin. The synthesis have been done using two different approaches, in first case organic solvent DMSO along with DI (De-Ionized) water have been used to dissolve Quercetin whereas during the second procedure DI water have been solely used to dissolve Quercetin. UV–vis absorption spectroscopy, TEM and IR results give the confirmation of conjugation of Quercetin to PEGylated NPs. Controlled release has been observed for both pH environments with a maximum release for CPD-I with 95.89% at pH 7.4 whereas at pH 5 CCPD-I shows maximum release i.e. 76.10%. The antioxidant activity results provide that the Quercetin molecules retain their antioxidant properties after conjugation with PEGylated NPs. [ABSTRACT FROM AUTHOR]

In this paper, sewage sludge, a solid waste from wastewater treatment plant, which eagerly requires proper treatment was reused as solid support in the form of sewage sludge biochar, then modified with carboxymethyl chitosan to form a bio-adsorbent. Further, carboxymethyl chitosan coating on sewage sludge biochar improved carboxymethyl chitosan’s stability in water. The prepared bio-adsorbent revealed a shorter equilibrium time (<60 min) for Pb(II) adsorption and a superior capacity of 594.17 mg g −1 for Hg(II) adsorption, which are so far the best recorded performance achieved for chitosan based adsorbents. Additionally, the adsorbent was highly selective for heavy metal ions and it also presented a good stability and reusability for industrial applications. These outcomes demonstrate waste valorization through a green, facile and one-pot approach that turns the solid waste of sewage sludge into biochar adsorbent with propitious applications in the elimination of heavy metal ions from wastewater. [ABSTRACT FROM AUTHOR]

This paper reports the experimental results on synthesis of zirconium nitride from zircon sand through transferred arc plasma processing via carbothermal reduction and nitridation reaction. A mixture of zircon sand and carbon was processed in a transferred arc set-up in a stream of nitrogen gas. The influence of the amount of carbon and processing parameters such as input power and processing time on zirconium nitride phase formation and product morphologies were investigated by means of XRD and SEM-EDS respectively. Thermodynamic calculations were performed using free energy minimization technique to predict the conditions under which zirconium nitride is formed when zircon is processed in nitrogen atmosphere. Conversion diagrams were constructed for the ZrSiO 4 -C-N 2 system with different mole ratios of carbon. The experimental results show that the optimum mole ratio of carbon to zircon to convert zircon to zirconium nitride by this process is 1:4. Further, the results show that the plasma input power has a greater influence on the formation of zirconium nitride rather than the processing time. Experimental observations show that the optimum processing parameters for effective formation of zirconium nitride from zircon are 10 kW of plasma input power and 5 min of processing time under nitrogen environment. [ABSTRACT FROM AUTHOR]

Mullite ceramics with hollow whisker structure have been synthesized firstly through ordinary sintering process. The effects of Bi 2 O 3 and processing, on mullitization behavior and morphology development of mullite ceramics, derived from the mechanochemically activated mixture of Al 2 O 3 and SiO 2 , were investigated in this paper. When the content of Bi 2 O 3 was less than 10 mol%, the mullite grains show a short rod-like morphology, without the formation of whisker. As the content of Bi 2 O 3 was increased to more than 10 mol%, the formation temperature of mullite was decreased from 1400 °C to 1100 °C. After sintering at 1400 °C, well-developed mullite whiskers with hollow structure were formed. The formation process and growth mechanism of hollow structural whiskers in mullite ceramic doped with high content of Bi 2 O 3 were discussed in detail. [ABSTRACT FROM AUTHOR]

Resource utilization of ferrous sulfate waste has become a bottleneck restricting the sustainable development of the titanium dioxide industry in China. This paper proposes a new solution that utilizing ferrous sulfate waste to prepare spinel-structured magnesium ferrite (MF) particles in micrometer size, through the solid-phase reaction between ferrous sulfate, magnesium sulfate and pyrite under nitrogen protection. Thermodynamics analysis and tubular reactor experiments were performed to analyze the synthetic process. The thermodynamic simulation results showed that the proposed method for synthesizing MF is feasible by controlling the proper molar ratios of raw materials and calcination temperature. Based on this, the reaction mechanism for MF generation via this route was deduced, and the effect of three key parameters including molar ratios of raw materials, calcination temperature and calcination time on the products were investigated. The properties of synthesized MF were characterized via X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Raman spectroscopy (RS), scanning electron microscope (SEM), and Brunauer–Emmett–Teller (BET) method. Results demonstrated that the as-synthesized MF has a spinel structure and exhibits a micrometre-scale architecture composed of particles with size of 100–300 nm. This green synthetic method of MF provides a promising way to utilize ferrous sulfate waste, because it is in accordance with the concept of recycle economics and worthy of commercialization. [ABSTRACT FROM AUTHOR]

The solid state electrolytes based on NASICON structure are widely researched for high-energy solid-state lithium batteries due to its non-flammability, high conductivity, wide electrochemical window and easy process ability. In this paper, Li 1+x+y Al x Ti 2−x Si y P 3−y O 12 (x = 0.3 and y = 0.4) ceramic electrolyte has been successfully synthesized by the solution-based method at calcining temperature as low as 650 °C. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and electrochemical impedance spectroscopy (EIS). The effect of preparation conditions on the morphology, crystallinity and ionic conductivity of Li 1.7 Al 0.3 Ti 1.7 Si 0.4 P 2.6 O 12 have been studied in detail. The results showed that the Li 1.7 Al 0.3 Ti 1.7 Si 0.4 P 2.6 O 12 powders have rhombohedral NASICON-type structure, and the Li 1.7 Al 0.3 Ti 1.7 Si 0.4 P 2.6 O 12 pellet sintered at 1000 °C for 6 h exhibits the highest total lithium-ion conductivity (1.33 × 10 −3  S cm -1  at room temperature) and the lowest activate energy (0.25 eV). Therefore, the solution-based method will be a significant route for the industrialization preparation of Li 1.7 Al 0.3 Ti 1.7 Si 0.4 P 2.6 O 12 . [ABSTRACT FROM AUTHOR]

Here, we report a series of novel anticancer self-healing double-network films. The first network is based on the dynamic interaction between the aldehyde groups on dialdehyde groups-modified poly (ethylene glycol) (DPEG) and amino groups on chitosan (CH), and the second one is the metal coordination-chelation interaction. The double-network films are synthesized and characterized. The spectroscopic data show the formation of double-network films and their properties. The film has the ability to heal the external mechanical cracks by itself. According to the results, the order of the self-healing property is as follows: (CH/DPEG) 15 film > (CH/DPEG) 15 -Ca 2+ film > (CH/DPEG) 15 -Zn 2+ film > (CH/DPEG) 15 -Cu 2+ film. The activity data show that metal chelation interaction causes different influence on antibacterial and anticancer activities of the double-network films. The order is (CH/DPEG) 15 -Cu 2+ film > (CH/DPEG) 15 -Zn 2+ film > (CH/DPEG) 15 film > (CH/DPEG) 15 -Ca 2+ film. This paper provides a novel view on the effects of metal chelation interaction on the film’s self-healing properties and its biological activities. Therefore, the prepared double-network films might be used in cancer treatment in clinical application as anticancer coatings. [ABSTRACT FROM AUTHOR]

In this paper, a new synthetic pathway is proposed for the system YIn 1- x Mn x O 3 , a bright blue inorganic pigment, discovered in 2009. Blue pigment samples with increasing concentration of Mn 3+ ( x  = 0.08, 0.12 and 0.16) were prepared using the complex polymerization method (CPM) and compared with those synthesized via solid state reaction. All powders, the amorphous precursor from CPM and the starting materials for solid state method, were calcined at 1000, 1100, 1200 and 1300 °C for 12 h, and the resulting blue pigments were characterized by X-ray diffraction (XRD), colorimetric system CIE L*a*b* and Near infrared (NIR) reflectance measurements. XRD patterns and Rietveld Refinement show that the lowest temperature at which single hexagonal phase (isostructural to YInO 3 ) is formed is 1000 °C for CPM method and 1300 °C for conventional solid state method, respectively. The L*a*b* values demonstrate that the coloration of powders prepared by CPM exhibit temperature dependence below 1300 °C, a color shade shift from grayish blue to intense deep blue is observed when heating the samples from 1000 to 1300 °C. Blue pigments obtained by CPM have smaller particle size due to low temperatures and excellent near-infrared reflectance comparable to those by solid state method. Thus, providing advantages for application process and energy efficiency. [ABSTRACT FROM AUTHOR]

The fabrication of a micro/nano-scale thermoelectric module is very challenging. In this paper, a reliable and efficient hybrid fabrication method for ultrathin thermoelectric devices based on the non-contact exposing, photoresist melting and microfabrication technology is presented. The total thickness of the thermoelectric module is about 1 μm. Twenty-one devices are fabricated successfully, of which each is composed of 127 pairs of thermoelectric legs connected in series with an average resistance of 25 Ω. Experimental results indicate that ultrathin thermoelectric device work stable and reliable, and demonstrate that the method presented is suitable for fabrication of thinner and higher integrality devices beyond TE devices in the micro-nanoscale range. Without a load and at the temperature of 150 °C, the output voltage and output current are 18.5 mV and 671.9 μA, respectively; summarily, at the temperature of 50 °C the output voltage and current are 6.1 mV and 240.1 μA, respectively. The peak output power density is 0.29 W/m 2 and 2.9 × 10 5  W/m 3 . In addition, a one-dimensional heat transfer model is established to obtain a quantitative characterization for further numerical modeling. The present research can provide a useful guide for the design of a micro/nano-scale thermoelectric device in the near future. [ABSTRACT FROM AUTHOR]

Electric discharge machining (EDM) is widely used to cut and shape the biomedical device substrates, following often a separate coating process to deposit another barrier layer to improve the corrosion performance. This paper presents an innovative single in-situ surface modification technique to deposit nano-hydroxyapatite (nHA) coating on biodegradable Mg-Zn-Mn alloy while shaping the device substrate via electric discharge machining (EDM). The key benefit of the technique is to carry out the whole process in a single setup, hence saving time and cost. The aim of the coating is to control implant's degradation rate and to improve in-vitro bioactivity with human cells. Morphology, elemental, and chemical composition of the nHA coated Mg-Zn-Mn surface were characterized by FE-SEM, EDS, and XRD, respectively, while microhardness is measured by a Vickers hardness tester. Corrosion tests were performed via potentiodynamic polarization measurements in a SBF (simulated body fluid) to evaluate the degradation kinetics. In-vitro cell culture study was carried out to evaluate biocompatibility and cell attachment onto the modified surface. Surface characterization results revealed that a biomimetic nHA containing interconnected nano-porosities of size 5-10 μm had been yielded on the substrate surface, which is beneficial for the apatite growth and osseo-integration. The deposited coating layer has comprised of Mg, Zn, Mn, O, Ca and P elements and formed intermetallic oxide phases, such as CaMg, Mg-Zn, Mn-CaO, Mn-P, and Ca-Mn-O, which improved the in-vitro corrosion performance. The degradation rate of Mg-Zn-Mn alloy was reduced by 90.85% from 0.82 mm/year to 0.07 mm/year by the deposition of nHA-coating layer. The microhardness of the modified surface was measured as 234 HV, which was 1.5 fold higher than the untreated surface. The corroded surface analysis showed that the dense intermetallic phases of nHA coating acted as a stable barrier layer, thus prohibiting the surface from degradation, and hence, improving the corrosion resistance. The in-vitro bioactivity analysis revealed that the nHA containing layer exhibited the superior bioactivity and promotes adhesion, growth, and proliferation of human osteoblastic MG-63 cells. [ABSTRACT FROM AUTHOR]

Principal component analysis has been presented in recent research as an accurate and efficient method to reduce the complex chemistry and kinetics of large reacting mechanisms. Following the reduction, the original variables are transformed and projected onto a set of independent, orthogonal variables maximizing the total variance in the system: the principal components. However, these new variables are difficult to interpret physically and may introduce instabilities in the low dimensional representation of the manifold. In the present paper we will show the benefits of coupling PCA to a rotation method: the interpretation of the principal components can be related back to the physics. The advantages of rotation are demonstrated on a PCA reduced model for modelling dissociation and excitation processes in nitrogen shock flows. [ABSTRACT FROM AUTHOR]

Here we demonstrate, a simple and solvent-free synthetic route for the production of FeS/Fe(0) functionalized graphene nanocomposite (G-Fe) via a one-step pyrolysis of seaweed biomass ( Ulva fasciata ). It is proposed that the natural abundance of both inorganic and organic sulfur in the seaweed induces the reduction of exfoliated graphitic sheets at elevated temperatures. FeCl 3 was employed both as the iron precursor as well as the templating agent. Iron doping played a dual-faceted role of exfoliating as well as activating agent, producing composite with high adsorption capacity for Pb 2+ (645 ± 10 mg/g), CR (970 mg/g), CV(909 mg/g), MO (664 mg/g), MB (402 mg/g) dyes and good recyclability (8 cycles). Pb 2+ adsorption was irreversible even at low pH values and the spent composite (G-Fe-Pb) was utilized for efficient Cr(IV) removal (̴100 mg/g). The adsorption data followed the pseudo second order kinetics while the equilibrium data fitted perfectly into the Langmuir adsorption equation. Further, a thin layer of composite was deposited on a filter paper by vacuum filtration which was tested under continuous filtration mode for RB5 dye removal. Preliminary results highlight the potential of this composite to be used in pretreatment steps in hybrid membrane processes for filtration of complex wastewater feeds. [ABSTRACT FROM AUTHOR]

In this paper a set of linear and star -shaped polylactides (PLA's) containing a different number of -OH end-groups (1, 2, 4, 6 and 8) were synthesized. To compare the extent of interactions between different end-groups, the OH end-groups were transformed to COOH end-groups. To attain the proper conditions of this transformation, the conditions were optimized for the chosen model and then used for all synthesized polymers. The structure of synthesized polymers were confirmed by SEC-MALS, NMR and ATR FT-IR analyses. It was shown that PLA's architecture and number of OH and COOH groups in a single macromolecule have an influence on a viscosity of their solution due to their self-organization. For star -shaped PLA's containing higher than four number of COOH end-groups, it has been observed for the first time that the effect of intramolecular interactions exceeds intermolecular interactions what strongly affect their properties in diluted and concentrated solutions. [ABSTRACT FROM AUTHOR]

In this paper we describe the synthesis and characterization of the Sr 2 CeO 4 :Eu 3+ nanopowder and possibilities of its application for temperature and high pressure sensing. The material was prepared using simple solution combustion synthesis. X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques have been used to confirm and characterize the prepared material. Time resolved analysis of emission spectra was achieved by using the streak camera system. Measured lifetime values of luminescence emission and the intensity ratios of spectral lines were used for determining the calibration curves for remote temperature sensing. We have analyzed sensitivity improvement of the intensity ratio method by using a temporal evolution of emission lines and simulation of delayed gating of one of them. Pressure effects on optical properties of Sr 2 CeO 4 :Eu 3+ nanophosphor are also investigated. [ABSTRACT FROM AUTHOR]

Optically Stimulated Luminescence (OSL) is the luminescence emitted from a previously irradiated with ionizing radiation material by exposure to light. The aim of this paper is to evaluate the Blue Stimulation Luminescence (BSL) and Infra-Red Stimulation Luminescence (IRSL) for CaF 2 :Ce produced by the Solution Combustion Synthesis (SCS) method. The results showed that the OSL response of CaF 2 :Ce is strongly influenced by post-combustion thermal sintering temperature and dopant concentration. OSL response to dose are of the same order of magnitude of Al 2 O 3 :C, indicating the possibility of use of this material for radiation dosimetry. [ABSTRACT FROM AUTHOR]

In this paper, a comparative investigation of the catalytic performances of Pd@TiO 2 and Pd@CeO 2 , core-shells nanocatalysts supported over functionalized alumina, for application to methane oxidation is presented. The results indicated that the Pd@CeO 2 /SiO 2 .Al 2 O 3 core-shell nanocatalyst exhibited higher activity and stability than the Pd@TiO 2 /SiO 2 .Al 2 O 3 nanocatalyst. Complete combustion of methane over the Pd@CeO 2 /SiO 2 .Al 2 O 3 nanocatalyst was achieved at about 400 °C. By contrast, the maximum combustion of methane over the Pd@TiO 2 /SiO 2 .Al 2 O 3 nanocatalyst was only attained at ∼550 °C. The Pd@TiO 2 /SiO 2 .Al 2 O 3 nanocatalyst experienced deactivation, and a transient dip in methane conversion in the temperature region between 580 °C and 750 °C was also observed. The exceptional activity of the Pd@CeO 2 /SiO 2 .Al 2 O 3 nanocatalyst was attributed to the intimate interaction between palladium (Pd) and ceria (CeO 2 ) and efficient oxygen back-spillover at Pd and CeO 2 interface resulting from the core-shell structure. [ABSTRACT FROM AUTHOR]

This paper demonstrates fine size-controlled synthesis of superparamagnetic carbon-encapsulated iron nanoparticles, by a supersonic plasma jet assisted rapid, bulk-production process, by manipulation of the pressure in the sample collection chamber. Transmission electron microscopy and small angle x-ray scattering measurements confirmed the formation of single-crystals with a narrow size distribution, having core average size of 5.0 nm and encapsulated by an ultrathin carbon coating, for sub-mbar pressure. VSM and Mossbauer characterization established the nanocrystallites to be superparamagnetic in nature, with saturation magnetization 67 emu/g and coercive field 7.4 Oe. Controlled plasma heating during synthesis led to the burning down of extra carbon that resulted in further enhancement of the magnetization of the product. Graphitization of the encapsulating layers also enhanced, which could successfully protect the metallic core from oxidation, as well as improved its cyto-compatibility. This purified sample could be ideal for targeted drugs delivery and water treatment applications. Another sample was processed through controlled reaction with oxygen, the as-synthesized sample having magnetic properties approaching that of the first sample, which may be more attractive especially for water treatment processes because of the simpler single-step processing of the material. [ABSTRACT FROM AUTHOR]

In the work the SHS synthesis of MAX phases from Ti-Si-C system were carried and initiated with use of 30 W laser beam with 40 µm spot. That kind of initiation allows locally and rapidly start the SHS synthesis and avoid the contamination coming from heating wire present during conventional method. The reaction was monitored by high-accuracy radiation pyrometer and high quality optical camera. The recorded data, together with reaction bed thermal conductivity measurements allowed to correlate to obtained powders composition and reaction speed. The reaction bed morphology was investigated by scanning electron microscopy with element distribution (EDS). The second part of the paper concerns laser reactive deposition of SHS in-situ synthetized MAX phases layer on silicon carbide substrate. The paths of deposited layer were formed under argon overpressure of 2 bar using 120 W of laser power. [ABSTRACT FROM AUTHOR]

In the current paper, the synthesis of RE 2 AlTaO 7 (RE = Gd and Yb) oxides was performed through a high-temperature sintering method using Gd 2 O 3 , Yb 2 O 3 , Al 2 O 3 and Ta 2 O 5 as raw chemicals. The phase-structure, micro-morphology and thermal-physical properties of RE 2 AlTaO 7 (RE = Gd and Yb) oxides were analyzed. The RE 2 AlTaO 7 (RE = Gd and Yb) oxides exhibit single pyrochlore-type crystal-structure. Compared to Yb 2 AlTaO 7 , the Gd 2 AlTaO 7 has greater thermal conductivity owning to relatively weaker phonon scattering. Because of higher electro-negativity of Yb, the Yb 2 AlTaO 7 has lower coefficient of thermal expansion than Gd 2 AlTaO 7 . The RE 2 AlTaO 7 (RE = Gd and Yb) oxides also exhibit no phase-transition between ambient and 1473 K. [ABSTRACT FROM AUTHOR]

It is a challenge to synthesize ultra-pure one-dimensional Ge 3 N 4 nanomaterials because the current synthetic approaches are difficult to avoid oxygen to form GeO x . In this paper, we provide a novel approach to synthesize ultra-pure Ge 3 N 4 nanowires by directly nitriding nanocrystalline Ge powder at a relatively lower temperature of 600 °C in NH 3 atmosphere. The nanocrystalline Ge powder is prepared using a liquid nitrogen cryomilling method, and an amorphous GeN x layer is formed on the surface of Ge powder to significantly block oxidation. The obtained single-crystal α-Ge 3 N 4 nanowires are ~ 80 nm in width and several tens of micrometers in length. The photoluminescence property of α-Ge 3 N 4 nanowires has also been investigated. The result exhibits a blue-green luminescence property with the main peak at 440 nm, which is originated from the electronic transition from the conduction band to valence band. [ABSTRACT FROM AUTHOR]

Nowadays the exploitation of conventional natural gas resources has been contributing to the problem of increasing CO 2 concentrations in the atmosphere and consequently increasing the global warming. The natural gas accounted for a majority of the feedstock used for methanol manufacture. Nevertheless, in the next years, methanol will have to be produced from less polluting sources that release small quantities of CO 2 and methane to the atmosphere. In this regard, the use of biogas for producing methanol appears to be a viable alternative. However, few studies have studied the optimization of methanol production plants from renewable sources. Thereby, the main purpose of this paper is to make a comparative analysis, throughout mathematical modeling and simulation, of different methanol production routes, by considering four biogas sources: landfill, palm oil effluent, corn cobs and sorghum fermentation. For all cases, an optimization study was performed, with the goal of maximizing the methanol production. The results evidenced that the biogas from palm oil showed to be the most profitable concerning the other sources. On the other hand, the landfill gas showed to be a very limited capacity for methanol supply. Finally, the process optimization indicate that the operating conditions must be adjusted with respect of the biogas composition, in order to allow the maximum production. [ABSTRACT FROM AUTHOR]

In , Nb , Mo-doped lithium complex phosphates and HZr 2 (PO 4 ) 3 with NASICON-type structure were synthesized in this paper. Particle size distribution lies between 50 and 300 nm. The obtained samples were characterized by X-ray diffraction analysis, scanning electron microscopy and X-ray microanalysis. Investigation of the catalytic properties of synthesized compounds in the C1 C2 alcohols conversions showed that heterovalent doping has a determining effect on the obtained catalysts' activity and selectivity. It is shown that the thermodynamic factors and the dopant ability to change the degree of oxidation and acid function of the catalysts play a key role in methanol and ethanol conversion. A number of catalysts show the high activity and selectivity of the formation of dimethyl and diethyl ethers and ethylene. High selectivity for C4 hydrocarbons is achieved by LiZr 2 (PO 4 ) 3 and Li 0.5 Zr 2 P 2.5 Mo 0.5 O 12 catalysts (64 and 49%, respectively) in the case of ethanol conversion. [ABSTRACT FROM AUTHOR]

In this paper, a new type of soluble polyester/silica (PE/SiO 2 ) hybrid was prepared by the ultrasonic irradiation process. The coupling agent γ -glycidyloxypropyltrimethoxysilane (GOTMS) was chosen to enhance the compatibility between the polyester (PE) and silica (SiO 2 ). Furthermore, the effects of the coupling agent on the morphologies and properties of the PE/SiO 2 hybrids were investigated using UV-vis and FT-IR spectroscopies and FE-SEM. The densities and solubilities of the PE/SiO 2 hybrids were also measured. The results show that the size of the silica particle was markedly reduced by the introduction of the coupling agent, which made the PE/SiO 2 hybrid films become transparent. Furthermore, thermal stability, residual solvent in the membrane film and structural ruination of membranes were analyzed by thermal gravimetric analysis (TGA). The effects of SiO 2 nanoparticles on the glass transition temperature (T g ) of the prepared nanocomposites were studied by differential scanning calorimetry (DSC). Moreover, their mechanical properties were also characterized. It can be observed that the Young's moduli ( E ) of the hybrid films increase linearly with the silica content. The results obtained from gas permeation experiments with a constant pressure setup showed that adding SiO 2 nanoparticles to the polymeric membrane structure increased the permeability of the membranes. [ABSTRACT FROM AUTHOR]

Herein, we report the successful surfactant free synthesis, characterization and visible light driven photocatalytic application of highly crystalline cobalt tungstate (CoWO 4 ) nanoparticles. The synthesized nanoparticles were characterized by several techniques which revealed that CoWO 4 exhibited monoclinic phase of Wolframite structure, possess high crystallinity and grown in very high density. As the tungstate nanomaterials are hardly investigated as visible light responsive photocatalyst for the removal of organic pollutants in aqueous phase, thus, in this paper the photocatalytic efficiency of cobalt tungstate nanoparticles was estimated by monitoring the degradation of brilliant green dye under visible light irradiation. Approximately 94% brilliant green dye was degraded within 120 min of visible light illumination. Hydroxyl radicals were held to be accountable for the excellent photocatalytic performance. The present study offers an innovative approach stating that metal tungstates can also be considered as proficient visible light responsive photocatalysts for the degradation of hazardous organic contaminants from aqueous phase. [ABSTRACT FROM AUTHOR]

In this paper, SiO 2 -TiO 2 /paraffin phase change microcapsules with different contents of paraffin are prepared via sol-gel method. SiO 2 -TiO 2 act as a shell and paraffin is used as a core. Scanning Electron Microscope (SEM), Laser particle size analyzer, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffractometer (XRD), Differential Scanning Calorimeter (DSC) and Hot Disk are employed to characterize the morphology, chemical structure and thermal properties of SiO 2 -TiO 2 /paraffin microcapsules. The results show that there is no reaction between SiO 2 -TiO 2 and paraffin. The average particle size is 11.38 μm when the encapsulation rate of paraffin is 39.8%. The latent heat and the phase change temperature of the SiO 2 -TiO 2 /paraffin microcapsule is 93.7 J/g and 29.0 °C, respectively. After 1000 times of heat storage-release cycles, the latent heat of the microcapsule was decreased by 6.58% and the encapsulation ratio was decreased by 2.62%. The thermal conductivity of the microcapsule is 11.63% higher than that of paraffin. [ABSTRACT FROM AUTHOR]

For the first time, X-ray excited luminescence of Sr 2 MgSi 2 O 7 :Eu 2+ , Dy 3+ , an efficient persistent phosphor with good potential for lighting, biological imaging and photodynamic activation, is reported in this paper. A modified Sol-Gel method is used to synthesize Sr 2 MgSi 2 O 7 :Eu 2+ , Dy 3+ phosphors and their luminescence properties are highly associated with the synthesis conditions. The dependences of the X-ray excited optical luminescence and persistent luminescence of Sr 2 MgSi 2 O 7 :Eu 2+ , Dy 3+ on the reaction pH, temperature, ratio of Eu/Dy, and the calcination duration time are investigated and the association of the luminescence behaviors with the synthesis conditions is explored as a good strategy to optimize the phosphors for practical applications. [ABSTRACT FROM AUTHOR]