Ekaterina V. Parkhomchuk

Effect of Titania Regular Macroporosity on the Photocatalytic Hydrogen Evolution on Cd1−xZnxS/TiO2 Catalysts under Visible Light

Multiphase photocatalysts Cd1−xZnxS/TiO2 were synthesized through the deposition of solid solutions of cadmium and zinc sulfides on the surface of titania samples with different porous structures, including a 3D‐ordered meso/macroporous structure. The photocatalysts were characterized by a wide range of experimental techniques: X‐ray diffraction, high‐resolution transmission electron microscopy combined with energy‐dispersive X‐ray spectroscopy, N2 adsorption at 77 K, X‐ray photoelectron spectroscopy, and UV/VIS spectroscopy. The photocatalytic activity was tested in a batch reactor for the H2 evolution reaction from aqueous solutions of Na2S/Na2SO3 under visible‐light irradiation (λ=450 nm). The highest achieved photocatalytic activity was 1.8 mmol H2 per gram of photocatalyst per hour. The regular porous structure of titania was demonstrated to enhance the photocatalytic activity and stability of Cd0.4Zn0.6S/TiO2 samples.

Synthesis of Polystyrene Beads for Hard-Templating of Three-Dimensionally Ordered Macroporosity and Hierarchical Texture of Adsorbents and Catalysts

Methods of polystyrene beads producing with properties appropriate for catalyst and adsorbent synthesis have been investigated. Hierarchical silicalite-1 and Fe-silicalite-1 with zeolitic MFI structure, as well as three-dimensionally ordered titania, silica, alumina and zirconia have been prepared by hard-templating method using polystyrene beads. The materials were characterized by X-ray diffraction, scanning and transmission electron microscopies, low-temperature nitrogen adsorption technique and mercury porosimetry. Developed meso- and macroporous structure of the templated materials facilitated the supply of macromolecular reactants to the material surface and reduced the negative effect of byproduct deposition, resulting in favored advantages of the materials in a wide range of processes: hydroconversion of heavy oil, wet hydrogen peroxide oxidation of organic substrates in water, photocatalysis and gas chromatographic analysis. The obtained results of the material applications showed their potential attractiveness as catalysts and adsorbents.

Hierarchically porous materials built of Fe–silicalite nanobeads

Hierarchically porous zeolite materials built of closely and randomly packed uniform Fe–silicalite nanobeads were synthesized. The desired assembly of nanobeads was achieved by the centrifugation and sedimentation of nanozeolite suspension followed by drying and calcination. A micro/meso/macroporous Fe–silicalite material with spongy texture built of closely packed nanocrystals was designed using polystyrene latex as a supramolecular template. Large Fe–silicalite microbeads were synthesized to compare their structure with the nanocrystalline materials. The synthesized samples were characterized by laser diffraction analysis, X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, argon and nitrogen adsorption measurements, inductively coupled plasma optical emission spectrometry, UV visible diffuse reflectance spectroscopy and temperature-programmed desorption of ammonia. Fe–silicalite nanozeolite materials have shown high crystallinity, and possess micro- and meso/macropore surface areas and high specific pore volumes. Pellets built of closely packed nanocrystals have exhibited good mechanical stability in benzene and water. Calcined Fe–silicalite materials built of nanobeads were observed to contain highly dispersed ferric clusters no more than 1 nm in size. The 3 nm ferric clusters in the zeolitic microbeads resulted in the appearance of Lewis acid sites with medium strength, which are absent in the nanobeads. Catalytic performance of hierarchically porous Fe–silicalites was studied in the total oxidation of clarithromycin lactobionate by H2O2 at 323 K compared with Fe–silicalite microbeads. Hierarchical Fe–silicalites are more efficient catalysts vs. Fe–silicalite microbeads due to increased catalytic site accessibility.

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

Depolymerization of Birch-Wood Organosolv Lignin Over Solid Catalysts in Supercritical Ethanol

Artemiy B. Ayusheev*a, Oxana P. Tarana,b, Irina I. Afinogenovaa,b, Tatyana I. Mishchenkoa, Michael V. Shashkova,c, Kseniya A. Sashkinaa,c, Victoria S. Semeikinaa,c, Ekaterina V. Parkhomchuka,c Vladimir E. Agabekovd and Valentin N. Parmona,c аBoreskov Institute of Catalysis SB RAS 5 Lavrentieva, Novosibirsk, 630090, Russia bNovosibirsk State Technical University 20 K. Marx, Novosibirsk, 630092, Russia cNovosibirsk State University 2 Pirogova Str., Novosibirsk, 630090, Russia dInstitute of Chemistry of New Materials NAS of Belarus 36 F.Skorina Str., Minsk, 220141, Republic of Belarus

Template method for the synthesis of a heterogeneous fenton catalyst based on the hierarchical zeolite FeZSM-5

Zeolite h-FeZSM-5 with a hierarchical micro/macropore system has been synthesized in the presence of a template based on the close-packed polystyrene (PS) spheres, and the conventional zeolite FeZSM-5 has been obtained in the absence of a PS template. The zeolites have been characterized by X-ray diffraction, scanning and high-resolution transmission electron microscopy, and N2 sorption. The macropore walls of the hierarchical zeolite consist of ZSM-5 nanocrystals and amorphous globules of silica. Compared to the conventional zeolite, the hierarchical one has a high BET and external surface areas of 245 and 472 m2/g, respectively, and a high pore volume of 0.6 cm3/g. The catalytic properties of the Fe-containing zeolites were studied in the H2O2 decomposition reaction in the absence and in the presence of EDTA ligands and in the oxidation of low- and high-molecular-weight organic compounds by hydrogen peroxide at 25°C. Hierarchical zeolite h-FeZSM-5 is highly efficient in the oxidation of large molecules.