Titanosilicalite of the MFI type was obtained via a hydrothermal method. Its initial and annealed at 75 °C (TS-1P(75)) and 500 °C (TS-1P(500)) forms were studied by X-ray powder diffraction (PXRD), X-ray absorption spectroscopy (XAS-method), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), temperature-programmed ammonia desorption (TPD NH₃), and pyridine adsorption (Py). The full-profile Rietveld method allowed us to observe the presence of the organic template tetrapropylammonium hydroxide (TPAOH) in the framework voids, as well as to determine the silicate module (Si/Ti = 73.5) and the distribution of Ti⁴⁺ ions over the MFI-type structure sites (Ti atoms replace Si ones in two positions: T1 and T6). The coordination numbers of titanium (CNTi = 4.6 for TS-1P and TS-1P(75), CNTi = 3.8 for TS-1P(500)) were established by the XAS-method. The catalytic activity of titanosilicalites was found in the reactions of nitrous oxide decomposition (the maximal decomposition rate is demonstrated for the TS-1P(75) sample), allyl chloride epoxidation to epichlorohydrin (the best combination of all indicators was exhibited for the TS-1P sample) and propane conversion (maximum propane conversion, and butadiene and propylene selectivity were observed in both TS-1P(75) and TS-1P(500) samples). Mechanisms for the catalytic processes are proposed. The relationship between the catalytic properties and the composition (Si/Ti), Ti⁴⁺ ion distribution over the MFI-type structure sites, the local environment of titanium ions, and the number of acid sites in the titanosilicalites are discussed.

Features of propane conversion in the presence of samarium vanadite and samarium vanadate, both produced via solid-phase synthesis, are studied. It is shown that SmVO3catalyzes mainly the propane...

The paper deals with the synthesis and modification of metal–organic molecular sieves for the separation and sorption of СО₂ and СН₄. The metal–organic framework compound Сu₃(BTС)₂ was incorporated for the first time into the MeKS carbon matrix, which allowed stabilization of Сu₃(BTС)₂ and expansion of the stability range of the framework compound from pH 3.1–7.8 for Сu₃(BTС)₂ to pH 2.85–9.90 for Сu₃(BTС)₂/С. The structure and chemical composition of the products were proved by X-ray diffraction, X-ray fluorescence analysis, IR spectroscopy, and scanning electron microscopy. The textural characteristics of the material were determined from the results of adsorption tests with nitrogen, water vapor, and pyridine. The ability of both Сu₃(BTС)₂ and Сu₃(BTС)₂/С to accumulate СО₂ and СН₄ was examined. The modification increased the adsorption capacity for СО₂ and СН₄. The Сu₃(BTС)₂ modification improves the efficiency of the separation of СО₂ and СН₄ from H₂, О₂, N₂: The separation factors of CO₂ and CH₄ from inseparable H₂, O₂, and N₂ were 3 and 3.8, respectively.

Nanosized iron(III) oxide with an average particle size of 8–10 nm has been synthesized by the thermolysis of iron(III) acetylacetonate using diphenyl ether as a dispersion medium. Reduction processes in a hydrogen atmosphere in the presence of nanosized iron oxide and natural mineral hematite (Fe₂O₃) have been studied by the temperature-programmed reduction method. The activation energies of the reduction processes have been determined by the Kissinger method; it has been shown that, in the case of nano-Fe₂O₃, the activation energies are several times higher than the respective values observed for hematite. The adsorption properties of nano-Fe₂O₃ and hematite have been studied; the isosteric heats of chemisorption of hydrogen and carbon monoxide on the surface of these samples have been determined.

The influence of Yb³⁺ cations substitution for Pr³⁺ on the structure and catalytic activity of (Pr_1−xYb_x)₂Zr₂O₇ powders synthesized via coprecipitation followed by calcination is studied using a combination of long- (s-XRD), medium- (Raman, FT-IR, and SEM-EDS) and short-range (XAFS) sensitive methods, as well as adsorption and catalytic techniques. It is established that chemical composition and calcination temperature are the two major factors that govern the phase composition, crystallographic, and local-structure parameters of these polycrystalline materials. The crystallographic and local-structure parameters of (Pr_1−xYb_x)₂Zr₂O₇ samples prepared at 1400 °C/3 h demonstrate a tight correlation with their catalytic activity towards propane cracking. The progressive replacement of Pr³⁺ with Yb³⁺ cations gives rise to an increase in the catalytic activity. A mechanism of the catalytic cracking of propane is proposed, which considers the geometrical match between the metal–oxygen (Pr–O, Yb–O, and Zr–O) bond lengths within the active sites and the size of adsorbed propane molecule to be the decisive factor governing the reaction route.

Results of the application of a theory concerning elasticity of composite materials to calculate the elastic modulus of anodic aluminum oxide (AAO) are presented. The basis of the proposed AAO elasticity model is the assumption that the space of the anodic aluminum oxide may be represented as a composite material in the form of a matrix—bulk amorphous oxide filling the space between the pores reinforced by a hollow fiber with zero wall thickness. The maximum error of this simplification in the range of the actually used porosity values is 5% for the Young’s modulus and 0.7% for the shear modulus. The results are in proper agreement with the experimental data of other authors. Proper agreement of the results holds out a hope that this approach may be applied when the AAO pores are filled with some material (adsorbent, liquid, etc.), as is possible, for example, in cases of AAO application as a material for cantilever sensors.