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The necessity of development of technical solutions that will allow to reduce carbon monoxide emissions of flue gases of industrial productions is substantiated. It is shown that the most rational design solution to the problem of carbon monoxide pollution during the firing of electrode blanks is the use of aerated concrete blocks with a catalyst, which can be quickly and conveniently located directly on the carbon material of the "green" electrodes pouring in the subfloor space of the firing furnaces. Modified by oxides of Mn4+, Fe2+, Fe3+, Cu2+, Cr3+ -catalysts based on aerated concrete were obtained. It is shown that in an empty reactor in the temperature range 200 – 400 ºС the degree of conversion of carbon monoxide in the absence of a catalyst is zero. It is established that on the investigated catalysts based on aerated concrete 100% oxidation of carbon monoxide is achieved at a temperature of 390 ºC in the case of using a mixture of catalyst powders 30 % CuO + 70 % MnO2, 40 % CuO + 60 % MnO2, 50 % Fe (FexCr1-x) 2O4 + 50 % MnO2; 50 % Fe3O4 + 50 % MnO2. It is determined that the addition of ferrite catalyst powder in aerated concrete in a mixture or without manganese dioxide does not critically affect the mechanical properties of the products.

In a porous fractal medium, the transport dynamics is sometimes anomalous as well as the crossover between numerous transport regimes occurs. In this paper, we experimentally investigate the mass transfer of the diffusing agents of various classes in the composite porous particle with fractal geometry. It is shown that transport mechanisms differ at short and long times. At the beginning, pure advection is observed, whereas the longtime transport follows a convective mechanism. Moreover, the longtime transport experiences either Fickian or non-Fickian kinetics depending on the diffusing agent. The non-Fickian transport is justified for the diffusing agent with higher adsorption energy. Therefore, we speculate that non-Fickian transport arises due to the strong irreversible adsorption sticking of the diffusing molecules on the surface of the porous particle. For the distinguishing of the transport regimes, an approach admitting the transformations of the experimental data and the relevant analytic solutions in either semi-logarithmic or logarithmic coordinates is developed. The time-fractional advection–diffusion equation is used on a phenomenological basis to describe the experimental data exhibiting non-Fickian kinetics. The obtained anomalous diffusion exponent corresponds to the superdiffusive transport.

This work shows the inhibition property of the α-FeOOH nanoparticles on the oxidation reactions. The structure of the nanoparticles is confirmed by elemental analysis, FTIR, Mossbauer spectroscopy, TEM, and oxygen titration. We reveal that the α-FeOOH nanoparticles drastically inhibit the benzyl alcohol chain oxidation. The inhibition of the benzyl alcohol oxidation by the α-FeOOH nanoparticles is caused by the reactions between the nanoparticles and peroxyl radicals. Our finding suggests that the α-FeOOH nanoparticles may be used as an effective additive to preserve organic compounds from oxidation. Particularly, we illustrate that the α-FeOOH nanoparticles enhance the storage properties of motor fuel. The inhibition efficiency of the α-FeOOH nanoparticles may result in a variety of new applications of iron-containing nanoscale materials.

The intrinsic kinetics of the methanol dehydration to dimethyl ether (DME) over commercial ZSM-5 zeolite is studied both theoretically and experimentally to establish the rate equation of the process. A set of kinetic models based on Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) formalism is proposed for the methanol conversion to DME. The experimental verification of the developed models reveals an essential correspondence between the L–H kinetics and the experimental data. In contrast, E–R models provide an insufficient description of the methanol dehydration kinetics. In the frame of L–H formalism, it is shown that both, the associative and dissociative, mechanisms of the methanol dehydration are acceptable in the experimental scenario studied. The discrimination of the established models to choose the most realistic one is performed by comparing the estimated activation energies and adsorption enthalpies with the literature data.

The previously proposed approach to the calculation of hydrogen selectivity in ethanol steam reforming is extended to the reforming of other alcohols. It is shown that the same formulas for the calculation of hydrogen selectivity can be applied to different alcohols. A general rule of thermodynamics of steam reforming of alcohols is found, which states that the equilibrium composition of the reaction mixture is completely the same for all alcohols at the same process temperature when using the same carbon content in the initial alcohol-water mixture.

The catalysts based on natural zeolite-clinoptilolite of Sokyrnytsia deposit modified with oxides of Mn4+, Fe2+, Fe3+, Cu2+, Cr3+ were synthesized. It was determined that 100% conversion of carbon monoxide was achieved at a temperature of 390ºC wnen using the copper-manganese-oxide catalyst (30% CuO + 70% MnO2). It was shown that although the use of the manganese-oxide catalyst provided 92.8% of CO conversion degree, this catalyst had the most advantages for application compared to the other studied solids. The structural parameters of the manganese-oxide catalyst were determined using XRD, SEM, and nitrogen adsorption. The composition of the main elements of the catalyst samples was determined by micro-X-ray spectral analysis. It was shown that using the catalyst containers in chambers heated by flue gases in the fire channels of a multi-chamber furnace for baking of electrode blanks can be one of the constructive solutions to the problem of flue gas purification from carbon monoxide. The environmental safety of the copper-manganese-oxide catalyst application for the treatment of the flue gases of electrode production is justified by obtaining a catalyst from spent sorbents for purification of the manganese-containing natural water and its non-toxicity in the case of burial or storage in landfills.

The present work describes the economical two-stages catalytic CVD method of the nanocomposite of phosphorous-doped multi-walled carbon nanotubes with nickel (Ni/P-MWCNTs) from the solution of the ...

The structural and spectral characteristics of sulfated spherical mesoporous titanium dioxide (TiO2-S), obtained by hydrothermal sol–gel synthesis in the presence of sulfuric acid, are studied by XRD, SEM, BET, and IR spectroscopy. The acid–base and catalytic characteristics of TiO2-S and commercial TiO2 in the oligomerization of glycerol are compared. The activation of glycerol on the surface of the catalysts is studied by attenuated total reflectance Fourier IR spectroscopy (ATR-FTIR). It is found the high selectivity for diglycerides in the oligomerization of glycerol is determined by the presence of strong base sites on the surface of TiO2-S.

Background: Deposition of palladium nanoparticles from colloidal solution on various supports produces palladium catalysts with a predetermined size and concentration of the palladium nanoparticles, which allows to study the nanoparticle size effects and support influence on palladium catalytic properties. Objective: The goal of the present work was the development of a preparation method of systems supported on γ-Al2O3 palladium nanoparticles with a controlled size and determination of their thermal stability in oxidizing and reducing atmospheres. Methods: We demonstrated the preparation of Pd/γ-Al2O3 composite by precipitation of the size-controlled palladium nanoparticles with a narrow size distribution from colloidal solution. The composites were characterized by X-ray diffraction (XRD), and transmission electron microscope (TEM) methods. Result: The size and size distribution of the nanoparticles supported on γ-Al2O3 were found to be increasing upon precipitation due to strong Pd/γ-Al2O3 interaction. A significant enlargement of the supported nanoparticles occured at 300°C. The aggregation of the nanoparticles was observed at temperatures above 500°C resulting in an increase in their size. Conclusion: Our findings are not only applicable for the preparation of a model Pd supported on the γ-Al2O3 catalyst but could be applicable to the designing of the Pd-containing catalyst for important industrial high-temperature processes.

The diffusion kinetics may experience either standard or anomalous behavior. In a porous medium, a transport process may distinguish between the standard and anomalous diffusion. Herein, we perform an analysis of the diffusion concentration profiles in a hierarchically porous material using the standard and the time-fractional diffusion equations. It is shown that the mass transfer regime changes from the anomalous to the standard one regarding the temporal scale of the concentration profile. Particularly, at relatively short times, the mass transfer regime corresponds to the anomalous diffusion with the superdiffusive anomalous diffusion exponent. In contrast, at relatively long times, the standard Fickian regime is obeyed. The investigated phenomenon is assigned to the diffusion in different components of a porous material. The relevant physical model of the corresponding transition is discussed based on the Cattaneo-type diffusion equation. The relaxation time for the transport of the gaseous molecules in the porous medium was found to be in the range of 10–8–10–6 s.

Preparation of the graphene-containing fibers is an important step in the fabrication of advanced materials. However, using conventional techniques, e.g., wet or dry spinning, requires sophisticated recipes for fabricating the graphene oxide (GO) fibers because the GO dispersion has a low viscosity and it cannot be directly used for spinning. In this work, a simple and reliable procedure, injection spinning (IS), for a direct spinning of GO is reported. According to IS, the thin flow which is squeezed-out from a nozzle forms a flat fiber and provides the spinning drawing force to break the weak spinning thin flow of the GO water–ethanol suspension. The GO flat fiber is finally obtained by drying at a low temperature of 50 °C. The GO flat fiber is twisted and reduced by HI resulting in a production of the reduced GO (rGO) yarn. After passing the relevant characterization test, we show that varying the spinning speed changes the morphology of the rGO yarns on microscale without the appearance of appreciable changes on the nanoscale. The rGO yarns are characterized by high values of Young’s modulus about 1.5 GPa. An application is demonstrated using IS for flexible and wearable electronics.

The diffusion of methanol in a catalyst pellet containing H-ZSM-5 zeolite and aluminum oxide before and after coke deposition in the conversion of methyl alcohol into dimethyl ether and C2–C4 alkenes is studied. It is shown that the diffusion regime of methanol is anomalous and that the anomalous diffusion exponent does not depend on coke deposition of the catalyst. The discovered features are caused by the adsorption of methanol in the micropores, access to which is not fully restricted as a result of coke deposition.

The effect of neodymium addition in the composition of complex bismuth cuprates Bi2Sr2–xNdxCaCu2Oy (0 ≤ x ≤ 0.1) on their structural and electrophysical characteristics and catalytic properties is found. It is established that increase in the neodymium content is accompanied by antibate (inverse) change in the unit cell parameters, increased structural defectiveness, and slight increase of the superconducting temperature. The increased activity of the Nd-substituted cuprates in the oxidation of CO is due to increase in the defectiveness of the structure and the content of mobile oxygen in the crystal lattice.

Cyanate ester resin (CER) is an excellent thermal stable polymer. However, its mechanical properties are not appropriate for its application, with brittle weakness, and it has poor functional properties, such as luminescence. This work innovatively combines the luminescence property and the improved mechanical properties with the inherent thermal property of cyanate ester. A novel nanocomposite, CER/uMWCNTs/Eu, with multi-functional properties, has been prepared. The results show that with the addition of 0.1 wt.% of uMWCNTs to the resin, the flexural strength and tensile strength increased 59.3% and 49.3%, respectively. As the curing process of the CER progresses, the injected luminescence signal becomes luminescence behind the visible (FBV). The luminescence intensity of CER/uMWCNTs/Eu was much stronger than that of CER/MWCNTs/Eu, and the luminescence lifetime of CER/MWCNTs/Eu and CER/uMWCNTs/Eu was 8.61 μs and 186.39 μs, respectively. FBV exhibited great potential in the embedment of photon quantum information. Therefore, it can be predicted that CER/uMWCNTs/Eu composites will not only have a wide range of applications in sensing, detection, and other aspects, but will also exhibit great potential in the embedding of photon quantum information.

It has been shown that yttria-stabilized zirconia is an effective catalyst for ethanol to n-butanol Guerbet coupling. The variation of the calcination temperature allows an improvement in the catalytic characteristics of this material via stabilization of the tetragonal phase of zirconia, having higher basicity than the monoclinic one. The treatment of yttria-stabilized zirconia at an optimal calcination temperature of 500 °C induces the increase in surface basicity required for the aldol condensation step, along with a decrease in surface acidity, which is responsible for the side reaction such as ethylene formation. The catalyst obtained significantly exceeds in selectivity and n-butanol yield than individual zirconia and other oxide systems which have been studied in this reaction.

The sorption and diffusion of methanol and ethanol on Amberlyst 15 were studied by the quartz crystal microbalance technique in the temperature range of 20-120°C at relative pressure p/ps < 0.04. The heats of sorption (∆H) and the activation energy of diffusion (Ea) of methanol and ethanol were determined from the temperature dependence of the Henry constant and the effective diffusion coefficient of the alcohols in the gel phase of Amberlyst 15. The proximity of the ∆H and Ea values for each of the sorbates indicates that mass transfer within the Amberlyst 15 gel phase takes place by a sorption–desorption mechanism.

Ethanol conversion into n-butanol was performed over ZrO2–CeO2 mixed oxide catalysts. The effect of ceria content on the acid–base and catalytic properties of ZrO2–CeO2 compositions has been studied. The introduction of CeO2 additives into zirconia stabilizes the tetragonal phase of ZrO2 leading to an increase in basicity of the samples and, as a result, increases the activity of catalysts towards n-butanol. The highest ethanol conversion, selectivity and the rate of n-butanol formation were obtained over the ZrO2–CeO2 sample with 10% of ceria, which exhibited the highest concentration and strength of base sites. This sample consists of a solid solution of ZrO2–CeO2, whereas at higher concentrations of additive, CeO2 forms an individual phase.

The fractal dimensions of nanodispersed zirconia determined by the BET and SAXS methods are compared. The fractal dimensions were shown to depend on the characteristic dimensions of the surface areas determined by different methods. A method for calculating the surface fractal dimension using the difference between the specific surface obtained by the BET and SAXS methods is proposed.

The catalytic properties of N-doped hydrazine-reduced graphene oxide (N-RGO) and thermally reduced graphene oxide (TRGO) in the hydrogenation of ethylene by molecular hydrogen were studied. Samples of the TRGO and N-RGO were characterized by transmission and scanning electron microscopy, X-ray diffraction, and Raman and X-ray photoelectron spectroscopy. It was shown that decrease of the oxygen content in the reduced graphene oxide increases its catalytic activity.

A hierarchical porous material was prepared by embedding microporous ZSM-5 zeolite into the mesoporous alumina matrix. The presence of the micropores with the size relevant to zeolite ZSM-5 and the mesopores of 4 nm in diameter were justified from the low-temperature N2 adsorption and desorption isotherm data. Transport of various diffusants with significantly different molecule size, e.g. methanol, isopropanol, n-hexane, benzene, cyclohexane, and cyclohexanol, through the as-prepared material was studied. The diffusants molecule sizes (d) are chosen to be smaller or larger compared to the ZSM-5 zeolite micropore size (dm). For the diffusants with d > dm, the mass transfer was found to follow the second Fick's law of diffusion. In contrast, the diffusants with d

Multicomponent CoO-CeO2(SrO)-Pd(Pt) catalysts on ceramic monoliths of a honeycomb structure (synthetic cordierite) were shown to be efficient for the deep oxidation of methane. Based on the results of the studying the effect of Al2O3 as a second carrier-substrate, the content of CoO, modifying/promoting additives of strontium and cerium oxides, palladium, platinum on catalyst activities, it was found that a 4,9%CoO-4,9%CeO2-0,1%Pd/cordierite specimen is optimal for use in catalytic heat generators. The catalyst of this composition, with increased mechanical strength, thermal resistance and resistance to carbonization, provides CO free oxidation of methane in the stoichiometric mixture with oxygen. Bibl. 33, Fig. 4.

The methanol and the methane transport in the mesoporous zeolite-alumina pellet was studied. Varying the pellet’s size and the diffusant amount, the values of the diffusion coefficients were estimated. Previously, it had been demonstrated that the methane transport through the zeolite-containing pellet is described by the Fickian diffusion equation, whereas the methanol transport is described by the non-Fickian diffusion equation with either space-time-fractional or time-fractional derivative. In this respect, for calculating the diffusion coefficients, the standard diffusion and the time-fractional diffusion models were used for the methane and the methanol respectively. The relations between the obtained values of the methanol non-Fickian diffusion coefficients (0.0068–0.0276 cm2/sα) measured for unequal pellet sizes and various diffusant amounts were found to follow the temporal scaling with a fractional exponent equal to 1.17 ± 0.03, which corresponds to the time-fractional diffusion equation, in a concise manner. It supported a conclusion that the anomalous diffusion of the methanol is time-fractional. An essential applicability of the approach based on the analysis of the temporal diffusion coefficient scaling was additionally verified using the standard Fickian diffusion coefficients of the methane (0.00094–0.00376 cm2/s). In addition, we demonstrate that the investigation of the anomalous diffusion regime using the spatial scaling of the diffusion coefficient is restricted by the measurement of the diffusion length of a certain diffusant in a porous material.

On the basis of analysis and thermodynamic calculations of the reaction paths of the catalytic conversion of ethanol a two-step process is proposed for the production of propylene from bioethanol and catalysts for its implementation. The catalyst of the first step is used to convert the ethanol into acetone, and the catalyst of the second step is used to convert acetone into propylene. This makes it possible to get high selectivity for the target product.

It was established that modifying additives CeO2, SiO2, and H3PO4 change the catalytic properties of compositions based on ZrO2 in the conversion of ethanol into 1-butanol due to a change in the phase composition of ZrO2, which determines its acid–base properties. As a result of stabilization of the tetragonal ZrO2 phase with additions of CeO2 and H3PO4 an increase in basicity occurs, leading to an increase in the selectivity and productivity of the catalysts in 1-butanol.

The nature of active acid sites of zeolite H-BEA with different Si/Al ratios (15–407) in liquid phase etherification of isobutylene with ethanol in a continuous flow reactor in the temperature range 80–180 °C has been explored. We describe and discuss data concerning the strength and concentration of acid sites of H-BEA obtained by techniques of stepwise (quasi-equilibrium) thermal desorption of ammonia, X-ray diffraction, low-temperature adsorption of nitrogen, FTIR spectroscopy of adsorbed pyridine and solid-state 27Al MAS NMR. The average values of the adsorption energy of NH3 on H-BEA were experimentally determined as 63.7; 91.3 and 121.9 mmol g−1 (weak, medium, and strong, respectively). In agreement with this, a correlation between the rate of ethyl-tert-butyl ether synthesis and the concentration of weak acid sites (ENH3 = 61.6–68.9 kJ mol−1) has been observed. It was concluded that the active sites of H-BEA for this reaction are Bronsted hydroxyls representing internal silanol groups associated with octahedrally coordinated aluminum in the second coordination sphere.

Simultaneous production of propene and hydrogen from ethanol is the promising way of a renewable feedstock conversion into valuable products. Propene is used for the production of polypropene plastics, acrylonitrile, propene oxide, and many other manufactures; hydrogen is considered the most viable energy carrier for the future. Conventional reaction schemes of the direct one-step catalytic conversion of ethanol into propene include the reaction of the isopropanol dehydration to propene. However, the dehydration ability of a catalyst inevitably gives rise to the ethanol dehydration to ethene that diminishes the propene yield. To avoid ethanol dehydration to ethene, the two-step process is composed of the ethanol conversion to acetone in the first step and the acetone conversion to propene in the second step. The thermodynamic analysis of the known reaction pathways for the ethanol conversion to propene shows that a 74.6% yield of propene can be achieved even at a low temperature of 200oC. According to the literature data, possible catalysts can be Cu/La2Zr2O7 or Fe3O4 for the first step, and the mixed Ag–In/SiO2 and K3PW12O40 catalyst for the second step. We speculate that the propene yield may reach 72% using these catalysts in the two-step process.

Nitrogen-doped reduced graphene oxide (N-RGO) was synthesized by the treatment of graphene oxide with hydrazine. The obtained material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman , nitrogen adsorption-desorption isotherm, and XPS. The catalytic activity of N-RGO in acetylene, ethylene hydrogenation, and preferential acetylene hydrogenation in the ethylene excess was determined. In the acetylene hydrogenation, the selectivity of 97% for ethylene is achieved. A possibility of a complete conversion of acetylene to ethylene in the acetylene-ethylene mixture with ratio 1:9 is shown.

In this work, multi-walled carbon nanotubes (MWCNTs) with significantly different mean diameters were produced by catalytic CVD over Ni and Co-based supported catalysts. Our results indicate that Ni nanoparticles in the Ni/MgO catalyst are responsible for controlling the inner diameters of the carbon nanotubes. Contrary, Co nanoparticles in the Co/MgO catalyst control the outer diameters of MWCNTs. The “base-growth” mechanism and smaller diameters of the MWCNTs grown on the Ni/MgO catalyst are associated with a strong metal-support interaction (SMSI) resulting from NixMg1−xO mixed oxide formation. The concept of the weak metal-support interaction (WMSI) between Co nanoparticles and MgO for the Co/MgO catalyst confirms the “tip-growth” mechanism of the MWCNTs.

It was shown that a catalyst obtained by depositing palladium nanoparticles from a colloidal solution onto a carbon support stabilized with polyvinylpyrrolidone exhibits higher activity in liquid-phase hydrogenation of o-nitrotoluene than a commercial sample of Pd/C with the same palladium content. From analysis of data from TEM, XRD, and XPS it was concluded that the increase of activity is due to the increased content of Pd0 in the synthesized catalyst.

This work shows, for the first time, that the multi-walled carbon nanotubes (MWCNTs) exhibit the catalytic activity in the ethylene hydrogenation. MWCNTs with the average diameter of 35 nm were prepared by CVD from ethylene as a carbon source at 700 °C. TEM, SEM, and XRD indicate that MWCNTs are characterized by a sufficiently high defectiveness. FTIR highlights that the catalytic process occurs in the presence of the hydroxyl and carbonyl surface groups. We demonstrate the high catalytic stability of MWCNTs at temperatures up to 400 °C.

Catalytic activity was shown for N-doped reduced graphene oxide (N-RGO), subjected to prior thermal reduction in a hydrogen atmosphere, in the hydrogenation of ethylene and acetylene. Samples of N-RGO and activated N-RGO (N-RGO-H2) were characterized by SEM, TEM, IR spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). Our results indicate the catalytic activity of N-RGO-H2 may be attributed to the presence of nitrogen-containing fragments, which may reveal frustrated Lewis pairs properties.

Although acid and catalytic properties of the sulfonic resins and zirconia are well-characterized, a little is known about their composites, particularly about the KU-2-8-ZrO2 composites, in which KU-2-8 is a commercial gel-type sulfonic resin. In this article, the acidity of the KU-2-8-ZrO2 composites has been studied by the ammonia quasi-equilibrium thermo-desorption technique and their catalytic characteristics in etherification of isobutylene with ethanol were defined. The KU-2-8-ZrO2 productivity in this reaction was found to be an order of magnitude higher compared to KU-2-8 and several times higher compared to the commercial macroporous sulfonic resin Amberlyst 15. A high productivity of the KU-2-8-ZrO2 composites is achieved by the improved accessibility of the sulfonic resin acid sites for reagents. The composites do not swell in the polar medium and show high resistance to osmotic shock. The KU-2-8-ZrO2 composites with 70–80 wt % of KU-2-8 were found promising for industrial applications.

It was shown that the structure of multilayer graphene oxide (GrO) synthesized by Tour method depends substantially on the degree of graphitization (g) and on the particle size of initial graphite. The obtained GrO was characterized by Raman and infrared spectroscopy, X-ray diffraction, and elemental analysis. The GrO contains carbonyl, carboxyl, and hydroxyl groups as well as C–O–C fragments. The dependence of the O/C molar ratio of GrO on the degree of graphitization of the parent graphite is nonmonotonic with a maximum at g ≈ 90%.

The methanol transport through the porous media, e.g., pelletized zeolite-based catalyst, was investigated. Standard Fickian diffusion equation was found to be inapplicable to a description of the experimental mass transfer kinetics. The diffusion equation with the fractional-order temporal and spatial derivatives was used in order to fit the experimental data. It is demonstrated that only the diffusion equation, which contains the time-fractional derivative or both, space–time-fractional derivatives, may thoroughly describe the experimental data. The measured time-fractional order is 0.85, which reveals the non-Fickian sub-diffusive transport through the pellet. The obtained fractional order allows the application of the continuous-time random walk model as a physical ground for the explanation of the measured non-Fickian transport. Contrary, using the space-fractional diffusion equation for the experimental data description leads to the inconsistent results similarly to the standard diffusion equation. The obtained findings reveal that the diffusate flux and the flux conservation law cannot be purely space fractional.

The diffusion regime (sub-diffusive, standard, or super-diffusive) is defined by the order of the derivative in the corresponding transport equation. We develop an accurate computational method for the direct estimation of the diffusion regime. The method is based on the derivative order estimation using the asymptotic analytic solutions of the diffusion equation with the integer order and the time-fractional derivatives. The robustness and the computational cheapness of the proposed method are verified using the experimental methane and methyl alcohol transport kinetics through the catalyst pellet.

The solutions of the time-fractional diffusion equation for the short and long times are obtained via an application of the asymptotic Green's functions. The derived solutions are applied to analysis of the methanol mass transfer through H-ZSM-5/alumina catalyst grain. It is demonstrated that the methanol transport in the catalysts pores may be described by the obtained solutions in a fairly good manner. The measured fractional exponent is equal to 1.20 ± 0.02 and reveals the super-diffusive regime of the methanol mass transfer. The presence of the anomalous transport may be caused by geometrical restrictions and the adsorption process on the internal surface of the catalyst grain's pores.

In the present paper, Thiele modulus (TM) for a catalytic reaction with the anomalous diffusion of a reagent in a catalyst pellet is introduced. Different cases of the TM are considered related to the anomalous diffusion process governed by a diffusion equation with the space-fractional, time-fractional, and space-time fractional derivatives. In addition, each fractional derivative is used according to the Caputo and the Riemann–Liouville definitions. Closed-form expressions of the TM for each definition of the fractional derivative are provided. For the time-fractional derivative, the TM is obtained under the assumption of the reaction dynamics nonlinearity. We demonstrate and critically discuss the applicability of the TM obtained for the reaction-diffusion equation with non-integer order derivatives to the evaluation of the parameters of the heterogeneous catalytic process.

In this letter, we provide an experimental study highlighting a relation between the anomalous diffusion and the fractal dimension of the environment using the methanol anomalous transport through the porous solid pellets with various pores geometries and different chemical compositions. The anomalous diffusion exponent was derived from the non-integer order of the time-fractional diffusion equation that describes the methanol anomalous transport through the solid media. The surface fractal dimension was estimated from the nitrogen adsorption isotherms using the Frenkel-Halsey-Hill method. Our study shows that decreasing the fractal dimension leads to increasing the anomalous diffusion exponent, whereas the anomalous diffusion constant is independent on the fractal dimension. We show that the obtained results are in a good agreement with the anomalous diffusion model on a fractal mesh.

The ultrasonic and the combined ultrasonic/mechanochemical treatments were used for the 1% СuO–MgO catalyst preparation by a simple mechanical mixing of the CuO nanopowder with MgO. Results of the ...