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Iron-containing catalysts promoted by nickel or cobalt were tested in methane decomposition reaction at low temperature (600–650 °C) and pressure 1 bar in order to study their catalytic properties and to produce catalytic filamentous carbon (CFC). Catalyst preparation method and composition of the catalysts were found to influence their properties. It was found, that introduction of cobalt or nickel in small amount (3–10 % mass) results in the magnification of carbon yields 2–3 times in comparison with Fe-Al₂O₃. Investigations of Fe-Co-Al₂O₃ and Fe-Ni-Al₂O₃ catalysts genesis were performed by Mössbauer spectroscopy, XRD, TEM. It is established that Co or Ni additives render activating influence on Fe catalysts which become apparent in decrease of the methane decomposition temperature and the formation of multiwall carbon nanotubes (MWNTs).

Ni, Pt, lanthanum nickelate with and without Pt supported on corundum carrier either pure or promoted with CeO₂–ZrO₂ were tested in partial methane oxidation (POM) to synthesis gas under conditions (high temperature, short contact time, highly diluted gas mixture, small catalyst grains) providing studying of the intrinsic kinetics. The phase composition and reducibility of catalysts were characterized with XRD and TPR technique. The influence of catalyst composition on the catalyst performance has been studied. The self-sustained oscillations of methane conversion and products concentration have been observed. The nature of those oscillations is discussed taking into account the intrinsic properties of the catalysts clarified with TPR and XRD.

In the present work, some data on catalytic combustion of one of the most widespread vegetative remainders – rice husk are adduced. The rice husk is used not only as a fuel, but also as a source of silicon for semiconductor industry, the synthesis of silicon carbides and silicon nitrides, etc. We studied the rice husk oxidation in the vibrofluidized bed of either a catalyst or an inert material in conditions allowing to reproduce with an adequate accuracy the data on scraps combustion in the dense and unloaded phase of the fluidized bed. It is found that the process of the rice husk combustion is localized completely in the bed of the catalyst. In the bed of an inert material the process occurs in a space above the bed; consequently, exhausts contain a fair quantity of CO. Studies on solid products of the rice husk combustion have shown that their texture is determined mainly by silica, which is contained in rice husk as amorphous silica SiO₂ × nH₂O. The adsorption ability of these solid products in respect to methylene blue (MB) is investigated. With increasing the process temperature, the value of limiting MB adsorption by the solid products passes through a maximum at the process temperature 600 °C. It is found that the values of the limiting MB adsorption for the solid combustion products in the bed of the catalyst exceed those for solid products obtained in the bed of an inert material. Under discussion are also some distinctions of the process of rice husk processing in the vibrofluidized beds of either catalyst or inert material.

Experimental data on the effective radial thermal conductivities and wall heat transfer coefficients of cylindrical beds formed of 4-hole and 52-hole cylindrical pellets, 6-spoke wheels and 3-hole trilobed particles are presented. A model with a linear variation of the radial thermal conductivity in the vicinity of the wall is proposed for description of the radial heat transfer in the packed bed. The model allows simple correlation between the wall Nusselt number and the bed core effective radial thermal conductivity. The model does not require any additional empirical parameters for the description of heat transfer in packed beds of different shaped particles.

The present paper reviews the processes of separation of microspheres from fly ash and their possible applications for the creation of catalytic supports, adsorbents and catalysts. To isolate magnetic microspheres and cenospheres of stabilized composition, the process flowsheets of concentrate separation, based on the combination of hydro- or aerodynamic and granulometric classification, followed by the separation in magnetic field of different intensity, were developed. Novel materials based on cenospheres of stabilized composition, such as mesoporous microspherical glasses (specific surface area S_sp = 3–50 m²/g), the supported iron oxide systems (S_sp = 50–200 m²/g), and zeolites are described. Spherical zeolites demonstrated good ion exchange properties of in cesium and strontium removal from the technological solutions. The catalytic properties of Fe₂O₃/cenosphere catalysts and magnetic microspheres in deep oxidation of methane are discussed.

The capability of combustion of solid fuels (such as the brown coal of the Kansk-Achinsk coal deposit) in the fluidized bed of an inert material in the presence of unmovable catalytic packages is investigated. This arrangement of the catalytic process is shown to allow the achievement of the same parameters of the fuel burn off and the content of toxic substances in the flue gas as in the case of fuel combustion in the fluidized bed of catalyst grains. The new arrangement of catalytic processes can be recommended for the accomplishing of some other exothermic catalytic reactions which require the maintenance of isothermal conditions.

With an increasing population, up to 9 billion, and oil as well as gas stocks being finite, we should reconsider sustainable raw materials, as provided annually by plants and trees and covered by the collective term biomass, as chemical feedstock. Carbohydrates are the

The effect of high temperature calcination and steaming on iron-containing zeolite was studied. Iron was introduced by sublimation of FeCl₃. FTIR measurements clearly show the disappearance of Broensted acid sites upon such treatments. This is attributed to a reaction between small occluded Fe oxide clusters obtained after initial low temperature calcination and the zeolite protons to give cationic Fe species compensating the negative zeolite charge. High temperature calcination and especially steaming considerably increase the catalyst activity in nitrous oxide decomposition. The two treated catalysts exhibit a higher apparent activation energy than the original sample. This high apparent activation energy is compensated by a high pre-exponential factor. In Fe/ZSM5 the activity mainly derives from small Fe oxide clusters, while upon treatment more active cationic species are generated. The kinetic parameters point to a stronger Fe–O bond for the latter case.

The semi-empirical Method of Interacting Bonds was used in the present work to clarify the mechanism of the title process. Various single crystal planes of Pt, Rh, Ir, Fe, and Re were examined with respect to the stability of the adsorbed NH_n species (n = 0, 1, 2, 3); to the reactivity of NH_n (n = 0, 1, 2) species towards adsorbed hydrogen atoms; and to the possibility of proceeding the combination reactions between two NH or two NH₂ particles resulting in the formation of gaseous H₂ and N₂ molecules. All the surfaces studied were found to form readily the stable NH species. The principal difference between Pt, Rh, Ir single crystal planes, on which the reaction exhibits rate oscillations, and Fe, Re surfaces, which do not show an oscillatory behaviour, is that the combination reaction of NH species can easily proceed in the former case, but this reaction is not allowed thermodynamically on the latter surfaces. This result is consistent with an earlier suggested mechanism for the oscillatory behaviour that attributes the surface wave propagation to the intermediate formation of NH species. Stable NH₂ species can be formed on Re and Fe surfaces, whereas the noble metal surfaces can form weakly stable NH₂ particles at the very edge of their existence region. The combination reaction between two NH₂ species is endothermic in all cases.

Detailed studies of the coadsorption of oxygen and carbon monoxide, hysteresis phenomena and oscillatory reaction of CO oxidation on Pd(110) and Pd tip surfaces have been carried out with the molecular beam (MB), field electron microscope (FEM), temperature programmed reaction (TPR) and X-ray photoelectron spectroscopy (XPS). It has been found that the occurrence of kinetic oscillations over Pd surfaces is associated with periodic formation and depletion of subsurface oxygen (O_sub). Transient kinetic experiments show that CO does not react chemically with subsurface oxygen to form CO₂ below 300 K. It has been found that CO does react with an atomic O_ads/O_sub state beginning at temperature ~150 K. Analysis of Pd tip surface with a local resolution of ~20 Å shows the availability of a sharp boundary between the mobile CO_ads and O_ads fronts.