The synthesis of highly porous ceramic materials for catalytic converters based on coarse-dispersed αAl2O3 was carried out using a combination of compaction and thermochemical synthesis methods with the participation of active ultrafine binders. Using XRD and SEM methods, it was established that the morphology of the synthesized material includes the simultaneous presence of large pores between the filler particles (the dominant αAl2O3 phase) and submicron pores in the transboundary areas that appeared during the processes of liquid-phase sintering and gas evolution. A significant amount of indialite Mg2Al4Si5O18 and spinel MgAl2O4, formed as a result of thermochemical synthesis on the surfaces and in the gaps between coarse particles, was revealed. Pores dominate (according to the volume of mercury intrusion) in the size range from 20 to 60 µm (about 73%), as well as from 0.4 to 2 µm (about 6 %). The average pore size is about 9 µm, the equivalent hydraulic diameter of the pore channels is about 3 µm. Highly porous materials with these characteristics of the pore space can be effectively used after modification as catalytic converters for the dehydrogenation of alkylaromatic hydrocarbons with a large molecular size (about 400 nm) with a long mean free path of about 3 – 4 μm.

The possibility of reusing mesoporous Sibunit as an adsorbent for 2,4-dichlorophenoxyacetic acid was studied. The effectiveness of using microwave radiation to restore the adsorption properties of the studied adsorbent was shown. A decrease in the average pore size on the surface of the Sibunit sample was noted as the adsorption–regeneration cycles were carried out without reducing the value of the adsorption capacity.

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A series of tubular porous ceramic converters modified with mono- and bimetallic catalytic systems based on rhenium and tungsten were prepared by a combination of self-propagating high-temperature synthesis and the sol–gel method. These converters were tested in dehydrogenation of ethylbenzene to styrene. Among the tested samples, a monometallic tungsten-containing converter exhibited the optimal properties as it achieved the highest target product production performance. Within the temperature range of 550–600°C, this converter provided a yield of styrene up to about 15 wt % and styrene productivity up to about 22 g h –1 dm –3 , with the carbonization of the sample not exceeding 5 wt % over about 6 h of reaction.

The adsorption activity of a carbon material based on lignin modified with iron salts and carbonized under the influence of microwave radiation in relation to 2,4-dichlorophenoxyacetic acid (2,4-D) from an aqueous medium was studied. The kinetic parameters of the adsorption process were determined. Based on the results obtained, the possibility of using the test material as an adsorbent of biologically active organic compounds was shown.

It was shown that the method for the incorporation of a catalytic tungsten component into a porous ceramic converter has a major effect on the activity and selectivity of cumene-to-AMS dehydrogenation. Specifically, the activity of a surface-modified tungsten-containing converter exceeded by more than 2.5 orders of magnitude the activity of a converter with tungsten incorporated by thermochemical sintering of the initial blend. It was further found that the performance of hydrocarbon dehydrogenation in converter channels nearly doubles that of the process occurring over a granular catalyst with an equivalent composition. It was also demonstrated that the process performance can be enhanced by removing extra-pure hydrogen from the reaction system through a palladium-containing membrane. Cumene dehydrogenation in catalytic converters was identified as a zero-order reaction.

The influence of the synthesis conditions on the performance of Pd–Cu ethanol-to-butanol conversion catalysts was studied. The optimum conditions for forming the most active system 0.2%Cu/0.3%Pd/Al 2 O 3 are as follows: sample synthesis by Al 2 O 3 impregnation from aqueous solutions of Pd and Cu nitrates; deposition of the metal precursors in succession; total content of Pd and Cu in the sample 0.5 wt %; Pd : Сu molar ratio 1 : 1; catalyst reduction temperature 200 ○ С. As shown by TEM, XPS, TPD-NH 3 , TPR-H 2 , XRD, and N 2 adsorption, the surface of the most active catalyst contains Pd 0 Cu 0 particles with the mean size of 4 ± 2 nm. The bimetallic particles are an alloy with the fcc structure and Pd : Cu ratio of 40 : 60. At 275 ○ C, the performance of 0.2%Cu/0.3%Pd/Al 2 O 3 is 182 × 10 –4 mol h –1 g –1 . The value obtained is higher by several orders of magnitude than the performance of the reference catalysts M 1 /Al 2 O 3 (M 1 = Fe, Ni, Co) and by an order of magnitude than that of the reference catalysts M 2 /Al 2 O 3 (M 2 = Ru, Rh, Pt, Pd, Pt–Re, Ni–Mo).

The study is devoted to the conversion of tar and iron-modified lignin under the action of microwave radiation. Lignin containing 0.5 wt % Fe absorbs about 80% of the supplied microwave radiation (2.45 GHz), which leads to a rapid increase in temperature in the reaction zone with the formation of plasma. During the conversion of a lignin (0.5 wt % Fe)/tar blend a wide range of gaseous and liquid hydrocarbons was produced, therewith the amount of light hydrocarbons was 75%. The solid carbon residue containing iron(III) oxide clusters is also characterized by the ability to absorb microwave radiation; it was employed as a catalyst and as a plasma generator in the 2nd cycle of the converting only tar under the influence of microwave radiation. The structure of nanosized iron-containing components was studied by transmission electron microscopy, X-ray diffraction, and Mössbauer spectroscopy, which made it possible to describe their genesis.

A porous ceramic catalytic converter was synthesized on the basis of a coarse α-Al2O3 powder filler using ultrafine strengthening binders of the MgO + SiC + SiO2 composition and catalytically active Re2O7 and WO3 components (up to 4 wt %). Double-sided compression of the starting mixture under a pressure from 70 to 90 MPa followed by sintering of the samples at temperatures from 1200 to 1400°C was applied. The synthesized ceramic catalytic converters possessed an open porosity of about 40% and a pore size of 0.5 to 1.5 μm. The styrene selectivity of about 30% and the productivity up to 30 g h–1 dm–3 in the temperature range from 600 to 700°С were experimentally achieved. The degree of catalyst carbonization within the experimental time (6 h) did not exceed 0.31 wt %. The scientific principles of a one-step technology for the synthesis of a porous ceramic with simultaneous imparting of catalytic properties thereto were developed. The obtained ceramic catalytic converters of the [Re,W]/α-Al2O3 composition can produce styrene with a high efficiency in a wide temperature range.

The interaction of the tobacco mosaic virus with the active surface of an iron-containing adsorbent obtained from lignin by the plasma-catalytic method was studied by IR spectroscopy. The results revealed decomposition of the virus into protein molecules and RNA reacting with the lignin surface via oxygen atoms during the binding of the virus to the sorbent surface. It was assumed that oxygen carboxylate groups interrelate with nanosized iron clusters incorporated into the adsorbent surface structure.

Photoelectrocatalytic oxidation of methanol was studied on thin-film nanocrystalline hematite electrodes prepared by the sol–gel method and doped by TiO2, Bi, and Co. The modification of hematite is shown to lead to its transformation into a material demonstrating high activity in the photoelectrochemical process of methanol oxidation under illumination in the visible range of the spectrum. According to the data of photocurrent modulation spectroscopy, this is due to a decrease in the rate of recombination of electron–hole pairs generated by light. Therefore, thin-film photoanodes based on modified hematite have good prospects for practical application in the photoelectrochemical degradation of organic pollutants.

Conversion of mixtures of fuel oil with iron-containing substrates (carbon adsorbent and lignin, both modified with 0.5 wt % Fe) to hydrocarbon products and hydrogen was studied. The use of microwave radiation in the presence of the above-indicated iron-containing substrates capable of its absorption with the generation of breakdown phenomena and plasma is a promising approach to rapid processing of stable organic compounds of petroleum and natural origin into hydrocarbon products used in organic synthesis and for production of fuel components.

An original approach to the carbon dioxide reforming of lignin modified with cobalt(ɪɪ) acetylacetonate is described. The cobalt-containing carbon residue is applicable as a catalyst for the microwave-assisted conversion of fuel oil. The combination of two processes stimulated by microwave irradiation may afford synthesis gas and a wide range of hydrocarbons, important petrochemicals, over a fairly short period of time.

Recently, a catalyst for the conversion of bioethanol to butan-1-ol and hexan-1-ol on the nanoparticles of PdxCuy alloy on the $$\gamma$$ -Al2O3 support was proposed. The catalyst possesses 90% selectivity and high activity with a conversion rate of 40–45%, together with high stability of operation – 20 cycles of 5-h catalytic runs at 275  $$^{\circ }$$ C. The key factor of its stability is the resistance to the CO poisoning. In the present work, we attempted to understand the effect of copper doping on the CO adsorption energy of the bimetal surface using density functional theory. We used the virtual crystal approximation to estimate the influence of the electronic structure of the bimetal as a whole and compared the results with the supercell approach. It was found that the shift of the d band center relative to the Fermi energy does not correlate with a decrease in adsorption energy with the increasing dopant (copper) content. At the same time, the changes in the surface structure and surroundings of the active center do decrease the calculated energy of CO adsorption, and this effect is achieved with a copper content of more than 60% atomic, which coincides with the copper content in the bimetallic particles of the working catalyst.

In this study, we present the results of lignin and fuel oil conversion to hydrogen, synthesis gas, and liquid hydrocarbons in the presence of nano-sized cobalt-containing systems in a microwave-assisted plasma catalytic process. The deposition of a small amount of cobalt on lignin increases its microwave absorption capacity and provides plasma generation in the reaction zone. The role of Co-containing particles in the above catalytic reactions is probably to activate the carbon bonds of lignin, which substantially increases the microwave absorption capacity of the system as a whole. The subsequent use of the cobalt-containing residue of lignin conversion as a catalytic system and MWI-absorbing material results in active fuel oil pyrolysis in a plasma catalytic process to afford gaseous and liquid hydrocarbons. In the plasma catalytic pyrolysis, fuel oil conversion is probably accompanied by the conversion of the organic matter of the residue and agglomeration of cobalt oxide particles.

The present study investigates the regularities in the conversion of ethanol and water/ethanol mixtures in the presence of Au–M/MFI/Al2O3 modified zeolite catalysts, where M = Cu, Ni, and Pd. The conversion products of ethanol, fusel oils, and of a model ethanol/acetone/1-butanol (ABE) mixture were investigated in detail. Transmission electron microscopy (TEM) revealed that supported metal particles mostly aggregate into bimetallic clusters 8–15 nm in size. The variations in product selectivity were found to be caused by coking and, therefore, by a declining concentration of acid sites on the catalyst surface.

This article presents the results of the development of membrane-catalytic methods for obtaining purified hydrogen of various degrees of purity required for feeding high-, medium-, and low-temperature fuel cells. In order to conduct this, porous ceramic catalytic converters were obtained using self-propagating high-temperature synthesis. These converters are suitable for high-speed processes for producing synthesis gas with different carbon monoxide content (0.08–0.1 vol. %), which can be used to feed fuel cells of various types. Using a hybrid catalytic membrane reactor, in which the stage of catalytic conversion of organic substrates was combined with the stage of selective extraction of ultrapure hydrogen (content of H2 was not less than 99.9999 vol. %) from the reaction zone, combined carbon dioxide and steam reforming of organic substrates of various origins were carried out. The result of the work was the creation of a prototype of a small-sized electric generator plant in which a catalytic membrane reactor was combined with a solid-oxide fuel cell.

This review focuses on pressing issues of photoelectrocatalytic degradation of organic pollutants of wastewaters on semiconductor materials upon their irradiation with both UV and visible light of the solar spectrum. Various photoactive semiconductor materials were considered, including titanium dioxide ( n -TiO 2 ), zinc oxide, tungsten oxide, hematite, and composites based on n -TiO 2 doped with metals, nonmetals, carbon, and polymer materials. The effect of structural factors and the electrolyte selection on the photoelectrochemical generation and the efficiency of active reagents for the oxidation of the main components of organic pollutants, as well as the effect of the electrolyte components adsorption on the photoelectrocatalytic characteristics of the electrodes have been demonstrated. Suggestions have been made on the prospects of the method of photoelectrocatalytic wastewater decontamination from organic pollutants.