Svetlana A. Yashnik

Supported honeycomb monolith catalysts for high-temperature ammonia decomposition and H2S removal

Abstract Catalysts that have potential in simultaneous removal of H 2 S and NH 3 decomposition were developed. The monolith supports of high surface area and acceptable mechanical strength based on titania and silica–alumina precursors were prepared and tested. Preparation routine and composition of Mn, Fe and Cu oxides supported honeycomb catalysts have been optimized. Impregnated and washcoated monolith catalysts were tested in ammonia high-temperature decomposition.

Catalytic and capacity properties of nanocomposites based on cobalt oxide and nitrogen-doped carbon nanofibers

Abstract The nanocomposites based on cobalt oxide and nitrogen-doped carbon nanofibers (N-CNFs) with cobalt oxide contents of 10–90 wt% were examined as catalysts in the CO oxidation and supercapacity electrodes. Depending on Co 3 O 4 content, such nanocomposites have different morphologies of cobalt oxide nanoparticles, distributions over the bulk, and ratios of Co 3+ /Co 2+ cations. The 90%Co 3 C 4 -N-CNFs nanocomposite showed the best activity because of the increased concentration of defects in N-CNFs. The capacitance of electrodes containing 10% Co 3 c 4 -N-CNFs was 95 F/g, which is 1.7 times higher than electrodes made from N-CNFs.

Development of Granular Catalysts and Natural Gas Combustion Technology for Small Gas Turbine Power Plants

Gas turbine power plants (GTPPs) of low power (tens of kW to 1.5-2 MW) are promising autonomous sources of energy and heat. The application of gas turbine technologies saves fuel, solves heat supply and water shortage problems. The nominal efficiency of GTTPs belonging to different generations varies from 24% to 38% (average weighted efficiency – 29%). This is 1.5 times higher than that of combined heat power plants. The main GTPP drawback is significant emission of toxic nitrogen oxides due to high temperature combustion of the gas fuel. The main approach used today to decrease the emission of nitrogen oxides from GTPPs is based on the use of the so-called homogeneous combustion chambers working with premixed lean fuel-air mixtures with two-fold excess of air. The decrease of NOx formation is principally the result of the low flame temperatures that are encountered under lean conditions (Correa 1992). This technology makes it possible to decrease significantly the temperature in the combustion zone relative to traditional GTPP combustion chambers with separate supply of fuel and air to the combustion zone. As a result, the concentration of nitrogen oxides in the flue gases decreases from 100 ppm to 1020 ppm. The downside of this approach is, however, that it results in low heat release rates, which, in turn, may negatively affect combustion stability. The most efficient way to decrease emissions of nitrogen oxides in GTPPs is to use catalytic combustion of fuel (Trimm, 1983; Pfefferle & Pfeferle., 1987; Ismagilov & Kerzhentsev 1990; Parmon et al., 1992; Ismagilov et al., 1995; Ismagilov & Kerzhentsev, 1999; Ismagilov et al., 2010). In the catalytic chamber, efficient combustion of homogeneous fuel-air mixture is achieved at larger excess of air and much lower temperatures in the zone of chemical reactions compared to modern homogeneous combustion chambers. In the last decade, the obvious advantages of the catalytic combustion chambers in GTPPs initiated intense scientific and applied studies in the USA (Catalytica) and Japan (Kawasaki Heavy Industries) which are aimed at development of such chambers for GTPPs for various applications (Dalla Betta et al., 1995; Dalla Betta & Tsurumi, 1995; Dalla Betta & RostrupNielsen, 1999; Dalla Betta & Velasco, 2002).

The Sulfur and Water Resistance of Modified Washcoated Zeolite-Exchanged Monolith Catalysts for SCR of NOx with Propane

The method of preparation of modified Cu-substituted zeolite DeNOx catalysts washcoated on monolith ceramics has been developed. Non-modified and modified monolith catalysts were tested in DeNOx reaction with propane. It was shown that the catalyst modified by cerium and containing titania together with H-ZSM-5 and Al2O3 in the washcoating layer demonstrates high level of activity, and its resistance during multiple cycles of poisoning by sulfur compounds and water at 400 and 500°C is also high.

Methane Catalytic Peroxide Oxidation Over Fe-Containing Zeolite

Vadim V. Boltenkov*a, Oxana P. Tarana,b, Ekaterina V. Parkhomchuka,c, Svetlana A. Yashnika, Kseniya A. Sashkinaa, Artemiy B. Ayusheeva, Dmitrii E. Babushkina and Valentin N. Parmona,c aBoreskov Institute of Catalysis SB RAS 5 Akad. Lavrentiev, Novosibirsk, 630090, Russia bNovosibirsk State Technical University 20 Karl Marx, Novosibirsk, 630092, Russia cNovosibirsk State University 2 Pirogova Str., Novosibirsk, 630090, Russia

Stabilization of copper nanoparticles in Cu-ZSM-5

Abstract The copper nanoparticles formed during reduction of Cu-ZSM-5 in hydrogen at temperature 150 – 400°C were studied by UV-Vis spectroscopy and HRTEM. The plasmon resonance (PR) absorption at 16000–17500 cm −1 was used for copper nanoparticles identification. It was shown that the chain-like and square-plain copper-oxide clusters stabilized in Cu-ZSM-5 during its preparation are the precursors of copper nanoparticles 2–10 nm.

χ-氧化铝的添加对纯的和修饰的γ-氧化铝上H 2 S氧化反应性能的影响

Abstract The influence of the textural and acidic properties of γ-Al2O3, (γ+χ)-Al2O3, and α-Al2O3 on the catalytic activity, selectivity, and stability of direct H2S oxidation has been studied. A comparison of the H2S-to-S conversion effectiveness of aluminas with their acidic properties (identified by Fourier transform infrared spectroscopy and temperature programmed desorption of NH3) shows that H2S adsorption occurs predominantly on weak Lewis acid sites (LAS). γ-Alumina samples containing a χ-phase and/or modified Mg2+ ions have a greater concentration of weak LAS and exhibit greater catalytic activity. When alumina is treated with a sulfuric acid solution, strong LAS appear and the number of LAS decreases significantly. Modification of alumina with hydrochloric acid has a limited effect on LAS strength. Weak LAS are retained and double in number compared to that present in the unmodified alumina, but the treated sample has Al−Cl bonds. Alumina samples modified by sulfate and chloride anions exhibit poor catalytic activity in H2S oxidation.

Effect of χ-alumina addition on H 2 S oxidation properties of pure and modified γ-alumina

Abstract The influence of the textural and acidic properties of γ-Al2O3, (γ+χ)-Al2O3, and α-Al2O3 on the catalytic activity, selectivity, and stability of direct H2S oxidation has been studied. A comparison of the H2S-to-S conversion effectiveness of aluminas with their acidic properties (identified by Fourier transform infrared spectroscopy and temperature programmed desorption of NH3) shows that H2S adsorption occurs predominantly on weak Lewis acid sites (LAS). γ-Alumina samples containing a χ-phase and/or modified Mg2+ ions have a greater concentration of weak LAS and exhibit greater catalytic activity. When alumina is treated with a sulfuric acid solution, strong LAS appear and the number of LAS decreases significantly. Modification of alumina with hydrochloric acid has a limited effect on LAS strength. Weak LAS are retained and double in number compared to that present in the unmodified alumina, but the treated sample has Al−Cl bonds. Alumina samples modified by sulfate and chloride anions exhibit poor catalytic activity in H2S oxidation.

Non-agglomerated silicon–organic nanoparticles and their nanocomplexes with oligonucleotides: synthesis and properties

The development of efficient and convenient systems for the delivery of nucleic-acid-based drugs into cells is an urgent task. А promising approach is the use of various nanoparticles. Silica nanoparticles can be used as vehicles to deliver nucleic acid fragments into cells. In this work, we developed a method for the synthesis of silicon–organic (Si–NH2) non-agglomerated nanoparticles by the hydrolysis of aminopropyltriethoxysilane (APTES). The resulting product forms a clear solution containing nanoparticles in the form of low molecular weight polymer chains with [─Si(OH)(C3H6NH2)O─] monomer units. Oligonucleotides (ODN) were conjugated to the prepared Si–NH2 nanoparticles using the electrostatic interaction between positively charged amino groups of nanoparticles and negatively charged internucleotide phosphate groups in oligonucleotides. The Si–NH2 nanoparticles and Si–NH2·ODN nanocomplexes were characterized by transmission electron microscopy, atomic force microscopy and IR and electron spectroscopy. The size and zeta potential values of the prepared nanoparticles and nanocomplexes were evaluated. Oligonucleotides in Si–NH2·ODN complexes retain their ability to form complementary duplexes. The Si–NH2 Flu nanoparticles and Si–NH2·ODNFlu nanocomplexes were shown by fluorescence microscopy to penetrate into human cells. The Si–NH2 Flu nanoparticles predominantly accumulated in the cytoplasm whereas ODNFlu complexes were predominantly detected in the cellular nuclei. The Si–NH2·ODN nanocomplexes demonstrated a high antisense activity against the influenza A virus in a cell culture at a concentration that was lower than their 50% toxic concentration by three orders of magnitude.