An approach to the development of bimetallic nanoparticles with the separated but interacting phases of silver and palladium was proposed to effectively separate the active sites of silver, which possess high activity in activation of molecular oxygen, and the sites of palladium containing phases, which are responsi ble for CO adsorption. The structure of PdAg particles was determined using X ray diffraction analysis, elec tronic diffuse reflectance spectroscopy, and temperature programmed reduction. It was found that the intro duction of silver led to easier reduction of palladium from oxidized states in an atmosphere of CO. The activ ity of the bimetallic PdAg catalysts in the oxidation of CO increased, as compared with that of the Pd/SiO 2 catalyst. The oxidized bimetallic catalyst, in which palladium occurred in an oxide state, was even more effec tive in the oxidation of CO; this can be related to the better cooperation of the active sites of silver and palla dium oxide, which are responsible for the activation and conversion of CO and oxygen at the Ag-PdO inter facial boundary.

Abstract.The method for identification of the triplet of kinetic parameters of a heterogeneous reaction using the data of the derivatographic analysis is proposed. This method is characterized by high accuracy and relative simplicity and it can be effectively realized using MS Excel software.Metal nanopowder is one of the most prospective high-energy materials that is widely used in many spheres [1,2]. This explains long and sustained interest in studying the features of metal nanopowder, in particular the kinetics of oxidation [3]. The proceeding heterogeneous reaction can be in full measure characterized by the so-called "kinetic triplet" -the frequency factor A, the activation energy and the mathematical description of the reaction mechanism f(α) [4,5,6].To identify these three parameters, the data of the derivatographic experiment conducted in the non-isothermal mode are used, when the change in the degree of transformation of the material α over time t is described by the differential equationUnder the temperature-linear heating where the rate of temperature increase T with a given parameter β = ⁄ and a specific mechanism (α) = (1 − α) , the kinetic equation (1) can be represented aswhere n -order (index) of reaction. Equation (2) has no analytical solution and numerical methods or approximate analytical ones are used to determine the kinetic parameters.The aim of this paper is to represent a quantitative result analysis of the derivatographic study of oxidation on the basis of a new approach to calculating the kinetic parameters of a  Corresponding author: bvborisov@tpu.ru

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Structure and properties of ZrO 2 and Al 2 O 3 powders produced using plasma chemical technique were studied in the framework of this research. Obtained Al 2 O 3 powder was used for reinforcement of Al alloy. Improvement of mechanical properties of Al alloy associated with introduction of alumina particles into the melt was demonstrated.

One of the key factors for producing highly dispersed controlled nanoparticles is the method used for metal deposition. The decomposition of metal-organic precursors is a good method for deposition of metal nanoparticles with very small sizes and narrow size distributions on the surface of various supports. The preparation process of Pd and bimetallic Pd-Sn nanoparticles supported onto γ‑Al2O3 is considered. The samples were prepared by diffusional co-impregnation of the γ‑Al2O3 support by using organometallic Pd(acac)2 and Sn(acac)2Cl2 precursors. To achieve the formation of Pd and bimetallic Pd-Sn nanoparticles on the support surface, the synthesized samples were then subjected to thermal decomposition under Ar (to decompose the organometallic bound to the surface while keeping the formed nanoparticles small) followed by an oxidation in O2 (to eliminate the organic compounds remaining on the surface) and a reduction in H2 (to reduce the nanoparticles oxidized during the previous step). A combination of methods (ICP-OES, TPR-H2, XPS, TEM/EDX) was used to compare the physical-chemical properties of the synthesized Pd and bimetallic Pd-Sn nanoparticles supported on the γ‑Al2O3. The three samples exhibit narrow size distribution with a majority on nanoparticles between 3 and 5 nm. Local EDX measurements clearly showed that the nanoparticles are bimetallic with the expected chemical composition and the measured global composition by ICP-OES. The surface composition and electronic properties of Pd and Sn on the γ-Al2O3 support were investigated by XPS, in particular the chemical state of palladium and tin after each step of thermal decomposition treatments (oxidation, reduction) by the XPS method has been carried out. The reducibility of the prepared bimetallic nanoparticles was measured by hydrogen temperature programmed reduction (TPR-H2). The temperature programmed reduction TPR-H2 experiments have confirmed the existence of strong surface interactions between Pd and Sn, as evidenced by hydrogen spillover of Pd to Sn (Pd-assisted reduction of oxygen precovered Sn). These results lead us to propose a mechanism for the formation of the bimetallic nanoparticles.

Abstract. Using the methods of mathematical modeling, the formation and evolution of aerosol clouds of toxicants in the atmosphere from the chemical industry enterprises, thermal power engineering and rocket carriers of space vehicles is analyzed. The processes of dynamic interaction of drops between themselves and a two-phase flow, processes of agglomeration, crushing and evaporation of aerosol particles are taken into account. The results of numerical calculations are presented.

Analytical estimation of particle shape formation parameters in a plasma-chemical reactor implementing the process of thermochemical decomposition of liquid droplet agents (precursors) in the flow of a hightemperature gaseous heat-transfer medium was obtained. The basic factor which determines the process is the increase of concentration of a dissolved salt precursor component at the surface of a liquid particle due to solvent evaporation. According to the physical concept of the method of integral balance the diffusion process of concentration change is divided into two stages: the first stage is when the size of gradient layer does not reach the center of a spherical droplet and the second stage when the concentration at the center of a liquid droplet begins to change. The solutions for concentration fields were found for each stage using the method of integral balance taking into account the formation of salt precipitate when the concentration at the surface of the droplet reaches certain equilibrium value. The results of estimation of the influence of various reactor operation parameters and characteristics of initial solution (precursor) on the morphology of particles formedmass fraction and localization of salt precipitate for various levels of evaporation.

The article considered the solution of the inverse problem of chemical kinetics of the analysis of experimental data of a thermogravimetric experiment at a constant sample heating rate. The fitting method for identifying the parameters of a kinetic triplet using the integral method for a model of a solid-state reaction based on the modified Arrhenius equation is described. The effectiveness of the proposed approach was confirmed by solving test cases for low, medium, and high rates of material conversion. Unlike other methods, setting the parameters of the reaction mechanism is not required, as they are determined by the solution. Solutions for real data of TGA studies with high and low sample heating rates were compared with the results obtained by other authors and experimental data. A description of the full cycle of calculations used to identify kinetic parameters from thermogravimetric experimental data is given, from the derivation of calculated relationships to the implementation of a short (three to five formulas) program code for MS Excel spreadsheets. The presented code is easy to verify and reproduce and can be modified to solve various problems.