Powders of catalysts from aluminides Fe and Co on a SiO2 support (33.3 wt. %) were obtained by mechano-thermal synthesis. The formation of large powder fractions (> 100 μm) was experimentally established. The fractions of these fractions for Fe – Al – SiO2 and Co – Al – SiO2 respectively amounted to ~ 43 % and ~ 55 %, which is a positive result for further catalytic studies. After annealing the powders at 700 and 900 °C in vacuum, the SiO2 support and compounds: Co27Al73 (close in composition to CoAl3, Co4Al13 type intermetallic compounds), Fe3Al intermetallic compound with iron silicide type Fe0.9Si0.1 and compound Al0,3Fe3Si0.7 in small volumes. On the synthesis of cobalt aluminides, a conclusion has been made about more efficient annealing at 900 °C than at 700 °C. For Fe – Al – SiO2 powders, it is advisable to anneal in the temperature range 700 – 750 °C with the assumption that the SiO2 support influences the thermosynthesis of iron aluminides. An experimental analysis of the morphology and elemental composition of the surface of the obtained samples is presented. It was found that the catalyst powders have medium sphericity and angularity. Fe – Al – SiO2 powders have a more developed surface than Co – Al – SiO2. Lower intermetallics are predominantly formed on the surface of the Co – Al – SiO2 sample. The correction of the mechanical alloying modes by means of the fragmentation of the process, changes in the intensity of its parameters, and various annealing conditions for Co – Al – SiO2 and Fe – Al – SiO2 are proposed.

High-entropy alloys were produced by centrifugal self-propagating high-temperature synthesis and used as precursors for preparation of catalysts for CO and propane deep oxidation and CO2 hydrogenation. The precursors were converted into catalysts by aluminum leaching and stabilization with hydrogen peroxide solution. Prepared FeCoNiCu, FeCoNiCuMo, FeCoNiCuMn, and FeCoNiCuCr catalysts were characterized by XRD, SEM/EDS, and BET methods and tested in the processes of deep oxidation of CO and propane and methanation of CO2. The highest CO2 conversion, 50.6

Nanocomposite materials based on palladium, copper(I) oxide, and magnetite nanoparticles embedded in a nanocellulose matrix by precipitation and coprecipitation methods were obtained in situ and ex situ from solutions of the salts of the corresponding metals. Studies of the characteristics of the resulting composites using Fourier transform IR spectroscopy, X-ray diffraction, SEM, and TEM showed that the encapsulated nanoparticles have an insignificant effect on the morphology and structure of nanofibrillar cellulose. The catalytic properties of the nanocomposites were tested in the hydrogenation of nitrobenzene.

NiAl, NiCoAl, and CoCuAl intermetallics on ceramic TiC and TiCrC supports were produced by self-propagating high-temperature synthesis (SHS) from granular mixtures and used as precursors for preparation of catalysts for CO and propane deep oxidation and CO2 hydrogenation. The precursors were converted into catalysts by aluminum leaching and stabilization with hydrogen peroxide solution. Prepared supported catalysts were characterized by XRD, SEM/EDS, and BET methods and tested in the processes of deep oxidation of CO and propane and methanation of CO2. It was revealed that 100 % CO conversion is observed in TiC-supported catalysts at 250 degrees C. Catalysts containing NiCo active phase on both ceramic supports were shown to be the most active in propane oxidation. In CO2 methanation, Ni/TiCrC sample showed the highest CO2 conversion (58.9 % at 350 degrees C) with 100 % methane selectivity.

Ni/TiC catalysts were produced by SHS from granular Ti + C + Ni mixtures and leaching in NaOH solution followed by stabilization with H2O2 solution of intermetallic precursors prepared by SHS from TiC + (Ni + Al) mixtures. Prepared granular and powder catalysts were characterized by XRD, SEM, EDS, and BET method. The catalytic activity of catalysts was determined in the temperature range of 150–400°С using the CO2 + H2 mixtures with different Н2 concentration. It was found that catalyst containing 10 wt % Ni leached from precursor with Ni : Al = 1 : 2 possesses the highest hydrogenating activity at 350°С and 20 vol % H2.

Supported mono- and bimetallic catalysts containing 10 wt

Copper and lanthanum promoted cobalt catalysts for CO2 hydrogenation to higher hydrocarbons are described. The catalysts were prepared by the self-propagating high-temperature synthesis followed by alkaline leaching. They are active in CO2 hydrogenation at 200 °C under 10 bar pressure (CO2 : H2 = 1 : 3) with selectivity to C2+ alkanes up to 39%; no alkenes and alcohols are formed under these experimental conditions.

Low-temperature combustion synthesis was used both for modifying silica gel support with 10 and 20 wt % Al2O3 and for producing supported catalysts with 10 wt % of Co active phase. Prepared catalysts were characterized by XRD, SEM, EDS, and BET method. It was revealed that these catalysts contain oxides, aluminates, and silicates of cobalt. It was shown that modification of support noticeably reduces its specific surface, while its calcination decreases the catalyst activity. The catalysts synthesized from supports with lower content of Al2O3 demonstrated higher specific surface and lower activity in deep oxidation of propane and CO. The catalyst on an uncalcinated support modified with 20 wt % Al2O3 was found to possess the highest activity in the process of deep oxidation.

Co–Ni supported catalysts were prepared by low-temperature combustion of dried mixture of solutions of cobalt and nickel nitrates and urea after impregnation of silica fabric (>97

Co–Al and Co–V–Al intermetallics produced by centrifugal self-propagating high-temperature synthesis (SHS) were used as precursors for preparation of catalysts for deep oxidation and hydrogenation of CO2. Leaching in NaOH solution and stabilization with H2O2 solution of precursors were carried out in permanent magnetic field (MF) (0.24 Т) and alternating magnetic field (0.13 Т, 50 Hz). Prepared Co и Co–V (95Co–5V, 90Co–10V) granular catalysts with size of 100–300 µm were characterized by XRD, SEM, EDS, and BET method and revealed to have a scaly surface structure. It was shown that the type of MF affects phase composition and surface morphology, as well as specific surface and activity in deep oxidation of CO and hydrocarbons as an important part of the neutralization of gas emissions, and hydrogenation of CO2, the processing of which would reduce atmospheric pollution with this greenhouse gas. Catalysts obtained in alternating MF was found to possess higher activity in the process of deep oxidation.

Previously, we suggested a new class of polymetallic catalysts based on SHS-produced intermetallic compounds for environment-friendly deep oxidation of CO and hydrocarbons [1]. Among these, Co–La catalyst showed best catalytic activity in the Fischer– Tropsch synthesis [2]. Since Co is also active in oxidation reactions [3], we made an attempt to further improve the oxidative ability of SHS-produced Co–La catalyst upon its modification with copper [4]. Moreover, Co and Cu catalysts exhibited high activity in the hydrogenation of СО2 [5–7]. Cu-doped Co–La catalysts of nominal composition (95 – x)Co–xCu–5La (x = 10, 30, 50 wt %) were prepared by centrifugal SHS from Co3O4–Cu2O–Al– La powder mixtures. As-prepared intermetallics were leached with NaOH, stabilized by processing in H2O2 solution (for details see [1, 2]), and characterized by SEM/EDS (Zeiss Ultra plus microscope + JCXA-733 Superprobe JEOL accessory) and XRD (DRON-3, Fe-Kα radiation). The 100–300 μm fractions of SHSproduced catalyst were tested for their activity in a flow silica reactor as described in [1, 2]. Gas compositions were determined using an Avtotest 02.03P gas analyzer and a gas-liquid chromatograph Model 3700.

Polymetallic Co90–V10 catalyst was derived from an SHS-produced Co–V–Al precursor and its performance in the deep oxidation of СО, propane and in the СО 2 hydrogenation was determined and compared with that of previously synthesized Co100 and Co95–V5 polymetallic catalysts. The precursor and catalyst were characterized by XRD, SEM, and BET analyses. In the processes of deep oxidation, Co90–V10 catalyst showed the best results. The CO 2 hydrogenation turned independent of V content of catalyst. A maximum of CO 2 conversion (65% at 350°C) was exhibited by Со100 catalyst. The СО 2 conversion over Co100 and Co95–V5 catalysts was found to show a maximum at a gas hour space velocity (GHSV) of 6000 h –1 .

The process of magnetic - field-assisted preparation of ferromagnetic Ni–Co–Mn catalyst for deep oxidation/hydrogenation from a mixture of SHS-produced intermetallics was explored by SEM, XRD, and BET methods. Alkali leaching of precursor powder was carried out in the absence of magnetic field, in permanent magnetic field (240 mT), and in alternating magnetic field (27 mT, f = 50 Hz). The application of MF during the preparation of Ni–Co–Mn catalysts was found to affect (a) their specific surface and morphology and (b) catalytic activity/selectivity in deep oxidation of CO and propane and hydrogenation of СО 2 . The effect of MF was more pronounced in the process of hydrogenation and in case of alternating magnetic field.

A new class of multifunctional polymetallic catalysts was developed, the precursors of which are complex multicomponent intermetallic compounds prepared by self-propagating high-temperature synthesis. The catalysts based on Co and Ni exhibit high activity in the hydrogenation of CO2 to methane. The maximum yield of methane is observed at 250–350 °C with an almost complete conversion of CO2 and 100% selectivity. Hydrocarbons C1-C4, including unsaturated hydrocarbons (propylene and butadiene), were synthesized on the Co-Fe-La catalyst under a pressure to 2 MPa at 250–350 °C and the ratio CO2: H2 = 1: 1. The new class of catalysts is promising for the development of direct CO2 hydrogenation to heavy (liquid) alkanes and unsaturated hydrocarbons.

Supported polymetallic catalysts (5–15% wt% of active phase) for deep oxidation and hydrogenation were successfully prepared by Self-propagating Surface Synthesis (SSS) using metal nitrates as oxidants and urea as a fuel. Commercial granules of γ-Al 2 O 3 ; NaA, NaX, ZSM-5 zeolites; and silica gel were used as supports. The synthesized catalysts were characterized by XRD, BET, and SEM/EDS. Catalytic behavior of the catalysts in a flow reactor was determined by gas–liquid chromatography, chemical analysis, and tested in deep oxidation of CO and propane as well as in hydrogenation of CO 2 to methane.

In the present study, the active phases (AP) of an Fe–Ni–Co–Mn catalyst produced from SHS-intermetallics (a), a catalyst prepared via formation an intermetallic layer on a mesh surface of chromium-nickel stainless steel (b), and of a Co–Mn catalyst prepared via SHS on silica gel support (c), were isolated and characterized by SEM and XRD. The catalysts studied were highly active in the process of deep oxidation and catalysts (b) and (c) were highly active in the process of CO2 methanation as well. All AP had oxo-metallic composition and were formed from nanoscale components, but if the structure of these components for catalyst (a) was the same as on the surface of the catalyst, the structures of AP components for catalyst (b) significantly differed from the surface structures. In addition, AP sediment grain nanostructures of catalyst (c) differed from those of catalysts (a) and (b).