Papers by Keyword: Catalysis

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Authors: Takashi Tokumasu
Abstract: The dissociation phenomena of H2 molecule on Pt(111) surface was simulated by Molecular Dynamics (MD) method and the effect of motion of the gas molecule or surface atoms on dissociation phenomena was analyzed in detail. The Embedded Atom Method (EAM) was used to model the interaction between an H2 molecule and Pt(111) surface. Using this potential, simulations of an H2 molecule impinging on a Pt(111) surface were performed and the characteristics of the collision were observed. Using MD data the dynamic dissociation probability were obtained and compared with the static dissociation probability to analyze the effect of atomic motion on dissociation phenomena.
Authors: Xiang Wen Kong, Han Wang, Zhao Jing Li, Jing Zhang
Abstract: Cyclohexyl ferulate was prepared by direct sterification of ferulic acid and cyclohexanol as raw materials with sodium bisulfate supported by silica as a catalyst. The influences of some factors on the synthesis process were studied. The optimal reaction conditions based upon 0. 2 mol of ferulic acid were chosen that the molar ratio of cyclohexanol and ferulic acid was 10 : 1, the mass ratio of catalyst to reactants was 5%, refluing reaction time was 3.5 hours, et a1. The yield of the product reached 80%. The structure of the product was characterized by IR, 1H NMR and MS spectrum. The catalyst could be recycled and used for many times, which is friendly to the environment.
Authors: AL Hassan Mohammed Nasser, Haitham M. Elbery, Hasan N. Anwar, Islam K. Basha, Hamada A. Elnaggar, Koichi Nakamura, Ahmed. A. El-Moneim
Abstract: In this work the Fischer-Tropsch synthesis reaction was catalyzed by reduced graphene oxide supported Fe nanoparticles catalysts in a fixed bed reactor. Also the influence of promotion by K and Mn on the catalytic activity of Fe nanoparticles was investigated. The systems showed acceptable CO conversions reaching as high as 96.2%. The selectivities of the C1-5 ranged from 38 to 62%. There was a very high CO2 selectivity which was explained by incomplete reduction of the catalysts. The Anderson-Schultz-Flory parameter was calculated and varied between 0.25 and 0.3. The strongest promoting effect was achieved by the K promoter which tended to reduce light product selectivities and CO2 production the most.
Authors: Jian Feng Ma, Jian Ming Yu, Bing Ying Cui, Ding Long Li, Juan Dai
Abstract: Inorganic-organic-bentonite was synthesized by modification of bentonite by Hydroxy-iron and surfactant, which could be applied in dye removal by adsorption and catalysis. The removal of acid dye Orange II was studied at various factors such as time and pH of solution. The results showed that the inorganic-organic-bentonite could efficiently remove the dye with efficiency of 96.22%. The maximum adsorption capacity is 76 mg/g. The pH of solution has significant effect on both adsorption and catalysis. When pH was 4, the maximum removal efficiency of adsorption and catalysis were 97.57% and 87.23%, respectively. After degradation, the secondary pollution was diminished and the bentonite could be reused.
Authors: Wei Wei He, Guang Fei Qu, Qian Zhao, Xiao Fen Li
Abstract: Magnetic Ionic liquids are a class of functional ionic liquids with magnetic. Because of outstanding thermal stability, excellent electrochemical properties, good solubility and recyclability, it has broad application prospects in catalysis, separation extraction, material synthesis and other fields. The main applications of magnetic ionic liquids in recent years are reviewed especially in the field of magnetic separation and catalytic. It shows a huge advantage that can highly efficiently catalyze myriads of reactions, and can be recovered and reused by a magnetic field. With the further research of magnetic ionic liquids, it is believed that the magnetic ionic liquid will be applied in more fields.
Authors: Ying Liu, Gang Xue, Jin Sheng Liang, Yan Ding
Abstract: The main properties of tourmaline are far infrared radiation, spontaneous polarization, widely used in the fields of saving energy and environment. Tourmaline as catalyst have extensive applications in the fields of environmental protection, fuel combustion, air purification, printing, deodorant, antibacterial, as well as wastewater treatment of dyeing and aquaculture.
Authors: Yi Yang, Hua Ping Bai, Xin Jie Yu, Jun Wang
Abstract: A relative standard deviation (RSD) method has been developed to evaluate the nanocatalyst dispersibility in an energetic polymer. The dispersibility of nanocatalyst and thermal characteristics of the polymer exhibits high dependence on the RSD of the concentration distributions of nanocatalyst. The improvement of the dispersibility of nanocatalyst, which is dependent on kneading time, can be presented by a decrease in the RSD of the concentration distributions. Moreover, the decomposition temperature and the combustion heat of the polymer is reduced gradually and enhanced distinctly, respectively, with the decrease of the RSD of the nanocatalyst distributions. However, over-kneading may lead to a reunion of nanocatalyst and a decline of thermal characteristics of the energetic polymer, and presented with an increasing of the RSD of the concentrations of nanocatalyst. The optimal kneading time is 3 h and an acceptable value of the RSD is approximately 1% of the concentration distributions of nanocatalyst for the energetic polymer with nanometer copper oxide catalyst.
Authors: Svetlana Chornaja, Reinis Drunka, Konstantins Dubencovs, Svetlana Zhizhkuna, Dzidra Jankovica, Janis Kunakovs, Aija Krūmiņa, Elina Sile
Abstract: Composites of Au supported on the TiO2-nanofibers (Au/NF-TiO2) were synthesized and tested in glycerol oxidation processes. TiO2-nanofibers were prepared by a microwave-assisted hydrothermal synthesis method. Chemical deposition method was used for nanofibers modification with Au nanoparticles. Oxidation of aqueous glycerol solutions by molecular oxygen in the presence of Au/NF-TiO2 nanocomposites was performed. It was found that Au/NF-TiO2 composites are catalytically active in alkaline glycerol water solutions. The main product of glycerol catalytic oxidation was glyceric acid, by-products were – tartronic, lactic, glycolic, oxalic, acetic and formic acid. It was shown that Au/NF-TiO2 catalysts’ activity and selectivity depend on Au weight loading, glycerol/Au molar ratio, oxygen pressure and NaOH initial concentration. The best result was achieved using the 0.5 wt%Au/NF-TiO2 catalyst: selectivity by glyceric acid was 76% with glycerol conversion 100%.
Authors: Denis V. Leybo, Natalia I. Kosova, Konstantin O. Chuprunov, Denis V. Kuznetsov, Irina A. Kurzina
Abstract: The possibility of bimetallic Ni-Mo nitrides usage as the catalysts in carbon dioxide hydrogenation reaction was examined in this work. Powders were synthesized through thermo-programmed reduction of precursor, which was produced by evaporation of the metal-containing solution. Specimens were investigated by x-ray diffraction, thermogravimetry, low-temperature nitrogen adsorption and scanning electron microscopy. It is shown that final powders provide CO2 conversion of 29 % for contact time of 0.26 s.
Authors: Volker Engels, Andrew E.H. Wheatley, Angel Berenguer-Murcia, David A. Jefferson, Brian F.G. Johnson
Abstract: Novel catalytic systems based on PdZn alloys have been synthesized by polyol reduction over the entire compositional range [1, 2] and characterized by means of HRTEM, EDS and ICP. The expected bulk compositions were reproducible to within a 2 mol% margin and the purified particle suspensions stable for several months after preparation. The EDS results indicated the presence of considerable amounts of oxygen, especially in those samples containing high fractions of zinc. The particle size distributions were shown to be narrow and the mean sizes slightly decreased with higher molar fractions of palladium (diameter range 2.6 to 3.2 nm). In the catalytic hydrogenation of phenylacetylene, a strong dependence of the substrate conversion time on the Pd concentration was established, and selectivity towards the semihydrogenation product (styrene) was found to be close to 100 %. The selectivity dropped only shortly before the initial substrate was fully depleted.
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