Dependence of the preparation method on the phase composition and particle size of the binary NiO–ZrO2 system oxides

Was studied how preparation method influences phase composition, oxide particle size and catalytic activity of the binary NiO–ZrO2 systems. The processes taking place under the thermal influence while NiO–ZrO2 catalysts are formed from precursors, obtained using a variety of methods, were determinated using the methods of simultaneous TGA-DTG/DSC analysis and XFA. Was studied the influence of the precursor preparation method upon the catalysts' phase composition, sizes of the nickel oxide and zirconium dioxide particles. The research revealed that preparation of precursor using coprecipitation method makes it possible to obtain a binary system, where nickel oxide has minimal size, determined by CSR, and monoclinic phase prevails in ZrO2, after heating it to 800 °C. The research unearthed that the catalyst exhibiting maximal catalytic activity by deep oxidation of methane is nickel oxide-zirconium dioxide, containing equal amounts of monoclinic and tetragonal phases of ZrO2

Synergistic effect in Ag/Fe-MnO2 catalysts for ethanol oxidation

Here we report the synergistic effect of OMS-2 catalysts tested in ethanol oxidation, and the effects produced by both the addition of an Fe modifier in the catalyst preparation stage, and the introduction of Ag on its surface by the impregnation method. To analyze the action of each component, the Fe-modified, Ag-containing OMS-2 catalysts with different Mn/Fe ratios were prepared. Combined XPS and XRF elemental analysis confirms the states and distribution of the Ag- and Fe-containing species between the surface and bulk of the OMS-2 catalysts, which form highly dispersed Ag species on the surface of 0.05Fe–OMS-2, and are also incorporated into the OMS-2 crystalline lattice. The cooperative action of Ag and Fe modifiers improves both reoxidation ability (TPO results) and the amount of adsorbed oxygen species on the catalyst surface. The introduction of Ag to the OMS-2 and 0.05 Fe–OMS-2 surface allows a high level of activity (T80 = 150–155 °C) and selectivity (SAc80 = 93%) towards the acetaldehyde formation

Manganese catalysts to obtain olefins from C1-C4 alkanes

Oxidative transformations of C1-C4 alkanes into olefins on oxide manganese catalysts were under study. We also studied oxidative coupling of methane (OCM) into ethylene on deposited and applied on the silicon dioxide catalysts. We studied the influence of chemical composition of catalyst and promotors on the OCM. Adding a little amount of ethane and propane hydrocarbons to methane allows increasing the concentration of ethylene in gases and significantly increasing productivity in ethylene. The study also shows the impact of the amount of manganese and promotors applied on SiO2 on the yield of olefins during the conversion of C3-C4 alkanes

Nickel-containing systems in reaction of partial oxidation of hydrocarbons

Nickel dispersion, which provides total catalytically active metal surface, is significant for partial catalytic oxidation of natural gas to obtain high purpose products yield and productivity in syngas. The interaction of reaction medium under high reaction temperatures during 20-25 hours promotes the increase of total square of active Ni component for block catalysts obtained with self-propagating high-temperature synthesis, which allows achieving productivity in syngas 7.1·103 cm3 (syngas)/cm3(catalyst)·hour. It is observed that for catalyst systems obtained with precipitation, chemical composition of oxide phase influences the particles size of metal nickel. For granular catalysts obtained through precipitation after 25-hour exploitation, average particle size (according to CSR) metal nickel is 3-4.5 times smaller than Ni in catalysts obtained with self-propagating high-temperature synthesis. This allows achieving productivity in syngas 8.1·103 cm3/сm3·hour, when there is average temperature decrease over the catalytic layer by ~100°С in comparison with blocks acquired through self-propagating high-temperature synthesis

Nickel-containing systems in reaction of partial oxidation of hydrocarbons

Nickel dispersion, which provides total catalytically active metal surface, is significant for partial catalytic oxidation of natural gas to obtain high purpose products yield and productivity in syngas. The interaction of reaction medium under high reaction temperatures during 20-25 hours promotes the increase of total square of active Ni component for block catalysts obtained with self-propagating high-temperature synthesis, which allows achieving productivity in syngas 7.1·103 cm3 (syngas)/cm3(catalyst)·hour. It is observed that for catalyst systems obtained with precipitation, chemical composition of oxide phase influences the particles size of metal nickel. For granular catalysts obtained through precipitation after 25-hour exploitation, average particle size (according to CSR) metal nickel is 3-4.5 times smaller than Ni in catalysts obtained with self-propagating high-temperature synthesis. This allows achieving productivity in syngas 8.1·103 cm3/сm3·hour, when there is average temperature decrease over the catalytic layer by ~100°С in comparison with blocks acquired through self-propagating high-temperature synthesis

Pyrolysis of 1, 2-dichloropropane

Process of pyrolysis 1, 2 dichloropropane to a allyl chloride have been studied. The reaction was carried out both homogeneously without a catalyst and using catalysts: quartz, waterless CaCl2; 15% mass. Cu/SiO2, 15% mass. CaCl2/Al2O3. It is shown that at 1, 2 dichloropropane conversion 15-40 % main pyrolysis byproducts were DCP is (cys-, trans-) 1-CP and 2-CP with trans-1-CP in most. At that parameters of pyrolysis, it is possible to achieve productivity by an allyl chloride 0.5-0.7 g/(ml⋅h)

The influence of manganese amount in oxyhydroxide of aluminium - precursor of MnOx-Al2o3 catalysts on catalytic activity in reaction of oxidation of C1-C3 of hydrocarbons

The authors have synthesized nanofibrous aluminum oxyhydroxide (AlOOH), modified with different amounts of manganese ions (II), which is the precursor for methane deep oxidation catalysts. It was shown that the catalytic activity of the manganese-based system obtained depends on manganese amount and thermal activation conditions. It is approved that as the catalyst for deep oxidation of hydrocarbons the system with manganese content of 10.5 wt. % is the most perspective despite the fact that the oxidation rate of methane is lower in it than in the catalyst with Mn content of 5.7 wt. %. As opposed to the catalyst with Mn content of 5.7 wt. %., where the aluminium oxide is in metastable form (s-Al2O3), the catalyst with manganese content of 10.5 wt. % contains in its structure a thermodynamically and thermally stable α-Al2O3 phase

The influence of manganese amount in oxyhydroxide of aluminium - precursor of MnOx-Al2o3 catalysts on catalytic activity in reaction of oxidation of C1-C3 of hydrocarbons

The authors have synthesized nanofibrous aluminum oxyhydroxide (AlOOH), modified with different amounts of manganese ions (II), which is the precursor for methane deep oxidation catalysts. It was shown that the catalytic activity of the manganese-based system obtained depends on manganese amount and thermal activation conditions. It is approved that as the catalyst for deep oxidation of hydrocarbons the system with manganese content of 10.5 wt. % is the most perspective despite the fact that the oxidation rate of methane is lower in it than in the catalyst with Mn content of 5.7 wt. %. As opposed to the catalyst with Mn content of 5.7 wt. %., where the aluminium oxide is in metastable form (s-Al2O3), the catalyst with manganese content of 10.5 wt. % contains in its structure a thermodynamically and thermally stable α-Al2O3 phase

Influence of concentration modifier on the structure and functional properties of aluminum oxyhydroxide modified

Studying the properties of nanomaterials is an important task, but nanomaterials with desired properties is a promising direction. The aim of this work is to investigate the influence of the value of the concentration of the modifier (ions Mn2+) on the structural and functional properties of modified aluminum oxyhydroxide. In this paper, using methods such as the X-ray diffraction studies, differential thermal analysis, electron microscopy, chromatography. The paper found that increasing the concentration of the modifier result in significant changes in the morphology, the appearance of metallic aluminum, which is well seen on X-ray data samples. The influence of thermal effects on a modified aluminum oxyhydroxide argon. Set the phase transition temperatures in the synthesized samples. It is shown that with increasing sodeozhaniya manganese in the composition of the synthesized samples decreases the value of specific surface area. Study of the functional properties showed that the synthesized material has catalytic properties in the oxidation of methane. It is shown that the effective sample is a sample with a manganese content of 2.7 wt. %. By XRD results calcined in air samples modified aluminum oxyhydroxide was shown that only in the sample with a manganese content of 2.7 wt. % MnAl2O4 phase is formed, which is catalytically active phase