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1.
The species resulting in CO, CO+H2 or CO+D2O adsorption on supported Ni catalysts were followed by IR spectroscopy and their role in methane synthesis mechanism is discussed.
- , CO, CO+H2 CO+D2O . .相似文献
2.
IR spectra of adsorbed CO species after prolonged contact with the catalyst surface show that surface carbon is formed and it participates in methane synthesis.
- , CO , , .相似文献
3.
L. I. Kuznetsova D. A. Karelin V. G. Chumakov S. V. Kachin 《Reaction Kinetics and Catalysis Letters》1991,44(2):401-407
Conversion mechanisms of CO, H2 and intermediates on Mo/SiO2 and Mo–K–SiO2 catalysts have been studied. It appears that alkaline promoters inhibit alcohol conversion to olefins and subsequent hydrogenation to paraffins. Active phase of the selective catalyst is MoO2 promoted by potassium.
CO H2 Mo/SiO2 Mo–K–SiO2 . . MoO2, .相似文献
4.
A. I. Suleimanov S. M. Aliev V. D. Sokolovskii 《Reaction Kinetics and Catalysis Letters》1986,31(2):291-296
It has been established that the introduction of CO2 and H2O to the reaction mixture when using freshly prepared catalysts, increases the overall methane conversion and decreases the yield of hydrocarbons. On coked MgO their effect is insignificant.
, CO2 H2O . MgO CO2 H2O .相似文献
5.
Yu. I. Pyatnitskii G. V. Filonenko V. P. Stasevich T. M. Shaprinskaya V. I. Gritsenko G. G. Girushtin 《Theoretical and Experimental Chemistry》1990,25(5):515-520
It has been established that the addition of oxygen to synthesis gas has a positive effect of the activity and selectivity of supported palladium catalysts in methanol synthesis. The degree of the effect of oxygen depends on the chemical nature of the support and the conditions of catalysis, preceding the addition of oxygen to the reaction mixture. The probable causes for the influence of oxygen on the catalytic properties of palladium, supported on oxide supports, have been discussed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 5, pp. 557–563, September–October, 1989. 相似文献
6.
The overtones of the stretching vibration of OH and OD were measured in solid solutions of H2O in D2O over a wide range of concentration and temperatures. The observed frequencies and the overall shape of the spectra were related to excitations of single OH or OD bonds (bound excitations) and those involving neighboring OH bonds extending over the crystal (non-bound excitations). The observed large anharmonicity of the bound state is interpreted as due to a low lying barrier in the double minimum potential curve for the hydrogen motion. 相似文献
7.
Guiying Wang Wenxiang Zhang Honglei Lian Qingsheng Liu Dazhen Jiang Tonghao Wu 《Reaction Kinetics and Catalysis Letters》2002,75(2):343-351
Catalytic decomposition of ethanol in the presence of steam over Pd supported on a porous carbonaceous material was studied. XPS and TEM were used for the catalyst characterization. Experiments were performed under atmospheric pressure, temperature of 320-360°C and H2O/C2H5OH molar ratio 8.1. It was found that the catalyst exhibited a high activity and long-term stability for the ethanol decomposition into a gas mixture containing carbon oxides, methane and hydrogen. 相似文献
8.
With increasing the lead content both CO and hydrogen sorption drop considerably. The influence of lead can be observed starting from a concentration of 0.5%. This may indicate that the surface is enriched in lead atoms.
CO, H2. , 0,5%. .相似文献
9.
Nickel/-alumina catalysts have been prepared by a version of the impregnation technique called double impregnation. The application of different organic reagents for activation of the -Al2O3 support promotes the formation of nickel-aluminate and large nickel crystallites in the catalysts obtained.
/- , . . . -Al2O3, -, .相似文献
10.
Run Xu Zhongyi Ma Cheng Yang Wei Wei Yuhan Sun 《Reaction Kinetics and Catalysis Letters》2004,81(1):91-98
The addition of iron and manganese has a strong effect on the Cu/ZrO2 catalyst performance for alcohols synthesis. The structures of catalysts have been investigated using X-ray adsorption spectroscopy and diffuse reflectance FTIR spectroscopy of absorbed CO. It is found that the Cu-Fe species and the interaction between them play an important role in converting the activity center for methanol synthesis to the center for higher alcohols synthesis.This revised version was published online in December 2005 with corrections to the Cover Date. 相似文献
11.
Matthew S. Johnson Keith T. Kuwata Chi-Kin Wong Mitchio Okumura 《Chemical physics letters》1996,260(5-6):551-557
The infrared spectrum of the ionic cluster I−(H2O) was recorded from 3170 to 3800 cm−1 by vibrational predissociation spectroscopy. A strong multiplet observed at 3415 cm−1 and a narrow band at 3710 cm−1 were assigned as a hydrogen-bonded OH stretch and free OH stretch respectively, indicating that H2O forms a single hydrogen bond with the iodide anion. Ab initio vibrational frequencies and intensities were computed at the second-order Møller-Plesset (MP2) level for the minimum energy configuration, a nearly linear hydrogen-bonded isomer, and for a low-lying saddlepoint, a symmetric C2v bridged isomer. The spectrum predicted for the hydrogen-bonded isomer agreed well with experiment. 相似文献
12.
The chemisorption of hydrogen on Ni/SiO2 has been studied by measuring temperature programmed desorption on various samples under various experimental conditions. Two peaks are found, which can be related to a weakly and to a strongly bound species of chemisorbed hydrogen. Their analysis has been performed by a method which makes possible to determine whether a certain kinetic model can describe the entire desorption process or to assign a clear meaning to the corresponding kinetic parameters.
Ni/SiO2 - . . , , , , .相似文献
13.
Xiao-Bing Cui Ji-Qing Xu Lan Ding Hong Ding Ling Ye Guo-Yu Yang 《Journal of Molecular Structure》2003,660(1-3):131-137
The compound [Zn(H2O)4]2[H2As6V15O42(H2O)]·2H2O (1) has been synthesized and characterized by elemental analysis, IR, ESR, magnetic measurement, third-order nonlinear property study and single crystal X-ray diffraction analysis. The compound 1 crystallizes in trigonal space group R3, a=b=12.0601(17) Å, c=33.970(7) Å, γ=120°, V=4278.8(12) Å3, Z=3 and R1(wR2)=0.0512 (0.1171). The crystal structure is constructed from [H2As6V15O42(H2O)]4− anions and [Zn(H2O)4]2+ cations linked through hydrogen bonds into a network. The [H2As6V15O42(H2O)]6− cluster consists of 15 VO5 square pyramids linked by three As2O5 handle-like units. 相似文献
14.
By metal impregnation of selected naturally occurring organic materials followed by controlled carbonization, metal semicoke catalysts can be readily prepared. These catalysts have been tested in the synthesis of hydrocarbons and alcohols from CO/H2 and CO2/H2 mixtures. Fe and Co preparations have been used. Relatively high temperatures are required when using these catalysts, which are quite active for synthesis using CO2 and H2. The pressure (5150 kPa) is very favorable both for the synthesis of liquid hydrocarbons (C5–C30) and alcohols (C1–C5).
. CO/H2 CO2/H2. Fe Co. , CO2 H2. 5150 ) (C5–C30) (C1–C5).相似文献
15.
The catalytic system methylaluminoxane (MAO) and bis(n-butylcyclopentadienyl)zirconium dichloride ((nBuCp)2ZrCl2) was immobilized on commercial silica, silica-alumina and aluminophosphate calcined at different temperatures. The properties of the supports were determined by using N2 adsorption-desorption isotherms at 77 K, FT-IR spectroscopy and SEM. After aluminium and zirconium impregnation, the catalysts were analyzed by ICP-AES, FT-IR and UV-vis spectroscopy. Ethylene polymerizations were carried out in a Schlenk tube at 70 °C and 1.2 bar of ethylene pressure. The polyethylene obtained was characterized by GPC, DSC and SEM.Catalysts supported on silica-alumina exhibited higher polymerization activity than those supported on silica and aluminophosphate. Besides, the activity of MAO/(nBuCp)2ZrCl2 catalytic system supported on silica-alumina and aluminophosphate decreased strongly with support calcination temperature, while remained almost constant when silica was employed as support. All these experimental features suggest a role of the support acid properties and hydroxyl group population in the generation of active polymerization species. 相似文献
16.
Jo o Batista Lopes Martins Elson Longo Octavio D. Rodr guez Salmon Vicente A.A. Espinoza Carlton A. Taft 《Chemical physics letters》2004,400(4-6):481-486
We have used the Oniom method with three layers in order to study the interaction of CO, H2, H2O, NH3 and CO2 molecules with the ZnO surfaces using a (ZnO)348 cluster model. The layers are divided into the high layer at the CCSD level, the medium layer at the RHF level and the low level layer using the UFF force field method. The orbital and binding energies of the adsorbed molecules, Mulliken and ChelpG charges as well as geometrical parameters were analyzed and compared with the available experimental and theoretical data. 相似文献
17.
A cobalt phosphonate (H3O)6·[Co4(H2O)4(HPMIDA)2(PMIDA)2)]·2H2O, 1, has been synthesized from a mild solvothermal reaction of Co(II) ion with N-(phosphonomethyl)iminodiacetic acid (H4PMIDA). Compound 1 crystallizes in the triclinic space group with cell parameters of , , , α=93.06(3)°, β=99.66(3)°, γ=90.34(3)° and Z=1. Compound 1 shows a novel tetra-nuclear molecular structure. In the crystal lattice, molecules of 1 hydrogen bond to each other to form two-dimensional (2D) layers, which are further linked together by the co-crystallized H2O molecules and H3O+ counter ions through hydrogen bonding to form the 3D supramolecular network. Thermogravimetric analysis, IR spectrum, magnetic susceptibility and luminescent spectra are given. 相似文献
18.
Filomena Gon?alves George E. Marnellos Evangelos A. Efthimiadis José L. Figueiredo 《Reaction Kinetics and Catalysis Letters》2003,80(1):153-159
The simultaneous reduction of N2O+NO with carbon supported Ni/K catalysts was studied. High conversions of both compounds were obtained at 400°C, and a synergystic
effect between Ni and K was observed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
Georgia D. Pappa Christophoros Perakis Ioannis N. Tsimpanogiannis Epaminondas C. Voutsas 《Fluid Phase Equilibria》2009
In order to evaluate the feasibility of CO2 sequestration in geological formations detailed knowledge of the mutual solubilities of the CO2/H2O system is required. In this work we employ three models, which all involve the well-known Peng–Robinson equation of state, to study the CO2/H2O phase equilibrium, with emphasis on the solubility of CO2 in the aqueous phase and the solubility of H2O in the CO2-rich phase. The considered models include the Peng–Robinson equation of state coupled with the conventional van der Waals one fluid mixing rules or the universal mixing rules, and the cubic-plus-association equation of state that uses the Peng–Robinson equation of state in order to account for the usual attractive and repulsive forces and an extra association term to account for the strong hydrogen bonding interactions. The required model parameters are calibrated using experimental data up to 1500 bar for pressure, and up to 673 K for temperature. To improve the accuracy of the proposed models we consider two temperature ranges. Temperatures lower than 373 K are of interest to the geological CO2 sequestration, while higher temperatures are of interest to fluid-inclusion studies. Good agreement is obtained between the experimental and the correlated solubilities. 相似文献
20.
R.D. Amos 《Chemical physics letters》1984,108(2):185-190
The dipole and quadrupole derivatives of H2O and H2S are calculated analytically, using the coupled Hartree—Fock method first proposed by Gerratt and Mills. The greater efficiency, of this method allows SCF wave functions very, close to the Hartree—Fock limit to be used. Agreement, with experimental data is good. 相似文献