Fabrication of ZnSe Thin Solid Films on the Cu Substrate and Investigation of Electrochemical,Adhesion and Solar Cell Properties by a New Technique

Russian Journal of Electrochemistry - Zinc selenide has applications in the fabrication of low-cost solar cells and optoelectronic devices. Due to its optical properties and large direct bandgap,...     

Nanoporous carbons as promising novel methane adsorbents for natural gas technology

Nanoporous carbons were synthesized using furfuryl alcohol and sucrose as precursors and MCM-41 and mordenite as nanoporous templates.The produced nanoporous carbons were used as adsorbent for methane storage.The average pore diameter of the samples varied from 3.9 nm to 5.9 nm and the BET surface area varied from 320m2/g to 824m2/g.The volumetric adsorption experiments revealed that MCM-41 and sucrose had better performance compared with mordenite and furfuryl alcohol,correspondingly.Also,the effect of precursor to template ratio on the structure of nanoporous carbons and their adsorption capacities was investigated.The nanoporous carbon produced from MCM-41 mesoporous molecular sieve partially filled by sucrose shows the best methane adsorption capacity among the tested samples.     

Synthesis,characterization and catalytic performance of nanosized iron-cobalt catalysts for light olefins production

Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods.     

Kinetic study of oxidative coupling of methane over Mn and/or W promoted Na_2SO_4/SiO_2 catalysts

A comprehensive kinetic model for oxidative coupling of methane(OCM)over Mn and/or W promoted Na2SO4/SiO2 catalysts was developed based on a micro-catalytic reactor data.The methane conversion and ethylene,ethane,carbon monoxide and carbon dioxide selectivities were obtained in a wide operating condition range of 750 - 825-C,CH4/O2=2.5 - 10 and contact time=267 - 472 kg s m-3.Reaction networks of six models with different rate equation types were compared together.The kinetic rate parameters of each reaction network were estimated using linear regression or genetic algorithm optimization method(GA).A reaction network suggested by Stansch et al.for OCM was found to be the best one and was further used in this work.The suggested model could predict the experimental results of OCM reaction within a deviation range of ± 20%.     

Synthesis of 2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) in aqueous medium at room temperature

The reaction of dimedone with various aromatic aldehydes produces 2,2'-arylmethylene bis (3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) in excellent yields. The reactions occur in water as solvent at room temperature and avoiding the addition of any catalyst. The workup procedure is very simple and the products do not required further purification.     

Crystal structure and DFT calculations of methanol {E-N′-(2-hydroxybenzlidene)benzohydrazido}dioxidomolybdenum (VI) complex

The crystal and molecular structure of methanol {E-N′-(2-hydroxybenzlidene)benzohydrazido}dioxidomolybdenum (VI) was determined by single crystal X-ray diffraction. B3LYP/DZP basis set theoretical calculations nicely reproduce the X-ray experimental geometry. The obtained results are discussed in connection with the electronic and structural properties of the compound.     

In situ crystallization of ZnAl2O4/ZnO nanocomposite on alumina granule for photocatalytic purification of wastewater

Research on Chemical Intermediates - ZnAl2O4/ZnO nanocomposites with different ZnO (20, 30, and 40 mol%) concentrations and coated samples on supports were successfully prepared through...     

Asymmetric Schiff base as carrier in PVC membrane electrodes for manganese (II) ions

Manganese(II) complex of (E)-2-(hydroxyl-5-methoxybenzylideneamino) phenol was synthesized and used as a suitable Mn(II) – selective membrane in PVC matrix. The plasticized membrane sensor exhibits a nersian response for Mn(II) ions over a wide concentration range of 6 × 10^?6–2 × 10^?2 M with slope of 29 ± 1 mV per decade. It has a response time of <11 s and can be used for 2 months without any measurable divergence in potential. The response of the proposed sensor is independent of pH between 4 and 9.5. The proposed sensor shows a fairly good discriminating ability towards Mn(II) in comparison with some hard and soft metals. The electrode was used in the determination of Mn(II) in aqueous solutions and as an indicator electrode in potentiometer titration of manganese ions against EDTA.     

Solid phase extraction of copper (II) by sorption on octadecyl silica membrane disk modified with a new Schiff base and determination with atomic absorption spectrometry

A simple, selective and reliable method for rapid extraction and determination of trace amounts of Cu (II) ions from aqueous samples using octadecyl-bonded silica membrane disks modified with bis-(3-methoxy salicylaldehyde)-1,6-diaminohexane and flame atomic absorption spectrometry (FAAS) is presented. Extraction efficiency, the influence of pH, flow rates, amount of ligand, and type and least amount of eluant were investigated. The linear dynamic range of the proposed method for Cu (II) ions was found in a wide concentration range of 1.0 (± 0.2)–150 (± 2) μg l^− 1. The detection limit and preconcentration factor of this method were found 30.0 (± 0.7) ng l^− 1 and 100 respectively. The reproducibility of the procedure is at the most 2.0%. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method was used to the recovery of copper ion from different synthetic, alloys and biological samples.     

Anodic stripping voltammetry of silver(I) using a carbon paste electrode modified with multi-walled carbon nanotubes

We describe a silver(I)-selective carbon paste electrode modified with multi-walled carbon nanotubes and a silver-chelating Schiff base, and its electrochemical response to Ag(I). Effects of reduction potential and time, accumulation time, pH of the solution and the stripping medium were studied by differential pulse anodic stripping voltammetry and optimized. The findings resulted in a method for the determination of silver over a linear response range (from 0.5 to 235 ng?mL^?1) and with a detection limit as low as 0.08 ng?mL^?1. The sensor displays good repeatability (with the RSD of ±?2.75 % for 7 replicates) and was applied to the determination of Ag(I) in water samples and X-ray photographic films.