Yu. V. Voronin

Catalytic properties of chromites with a spinel structure in the oxidation of CO and hydrocarbons and reduction of nitrogen oxides

The catalytic activity of supported chromites MCr2O4/γ-Al2O3 (M = Cu, Co, Mn, Zn, Mg) in the oxidation of CO, C3H6, and o-xylene and NOx reduction was studied. The catalytic activity depends on the calcination temperature and cation nature. The features of the formation of the catalysts were studied by the UV-Vis diffuse reflectance and IR spectroscopies.

Oxidation of CO and hydrocarbons over perovskite-type complex oxides

The catalytic activity of perovskites MIMIIO3 (MI=La; MII=Co, Mn, Cr, Al, Ni, and V) and MICoO3 (M=Y, Nd, Sm, and Er) in the oxidation of CO, propylene, and ethylbenzene was investigated. The highest activity was observed for the MICoO3 catalysts with perfect perovskite structure. The nature of the rare-earth element has no influence on the catalytic activity. Deformation of the octahedral coordination of the metal was found for the less active catalysts. The interaction of gases (CO, CO+air) with the catalyst surface was investigated. The more active catalysts adsorb a greater amount of O2, and the adsorption occurs in the temperature region of the oxidation reaction. The activities of the perovskite- and spinel-type catalysts were compared under similar conditions.

CATALYTIC OXIDATION OF CO, HYDROCARBONS, AND ETHYL ACETATE OVER PEROVSKITE-TYPE COMPLEX OXIDES

The catalytic activity of MIMIIO3] perovskite-type complex oxides (MI = La, Y, Nd, Yb; MII = Co, Mn, Ni) in the oxidation of CO, propylene, benzene, ethylbenzene,o-xylene, and ethyl acetate was investigated. The Co-containing catalysts were shown to be more active in the oxidation than the Mn-containing catalysts. A relationship between the catalytic and adsorption properties was established.

Catalytic properties of spinel-type complex oxides in oxidation reactions

The catalytic activity of MIMII2O3 spinel-type complex oxides (MI = Cu, Ni, Mn, Zn, Mg, Co, MII = Co, Cr, Al) in the oxidation of CO and ethylbenzene has been investigated. The Co-containing catalysts were more active than the Cr- and Al-containing catalysts. The nature of the cation influenced the catalytic activity. Higher activities were observed for the catalysts containing two transition elements. A correlation between the catalytic and adsorption properties was established.

Catalytic properties of ferrites in oxidation reactions

Catalytic activities of ferrites MFe2O4 (M = Cu, Co, Ni, Mg, and Zn) and M10.5M20 .5Fe2O4 (M1 = CU; M2 = Co, Zn, and Mg) in oxidation of CO and ethylbenzene were investigated, and their dependences on the cation nature were established. Higher activities were observed for catalysts containing ions with variable valence (Cu, Co, and Ni). A correlation between catalytic and adsorption properties of ferrites was found.

Regularities of formation and catalytic properties of supported cobaltites in the oxidation of CO and hydrocarbons and in the reduction of nitrogen oxides

The catalytic properties of supported cobaltites MCo2O4 (M=Cu, Mn, Zn, Mg) in the oxidation of CO, C3H6, and ethylbenzene and reduction of nitrogen oxides were investigated. The catalytic activity depends on the calcination temperature and the nature of the cation. The regularities of formation and the state of the surface of the catalysts were studied by IR spectra and diffuse reflectance spectra in the UV and visible regions.

Catalytic properties of manganites in the oxidation of CO and hydrocarbon

Manganites with a spinel structure MMn2O4 (M = Co, Cu, Zn, Mo) and M10.5M20.5 Mn2O4 (M = Co, Cu, Zn, Mg) have been synthesized and tested in the catalytic oxidation of CO, C3H6, and ethylbenzene. The dependence of the catalytic activity of the manganites on the nature of the cation has been established. The spinels containing transition metal ions (Cu, Co) are more active. A relation between catalytic and adsorption properties of manganites has been established. The participation of the lattice oxygen in the oxidation of CO to CO2 has been found. The mechanism of the oxidation is discussed.

Radiolytic Gas Formation in Dilute Oxalic Acid Aqueous Solutions

The radiolytic gas formation in aqueous oxalic acid solutions was studied. The concentrations of Н2 and СО2, the gas phase constituents, were measured. It was found that gas evolution is mainly due to the degradation of both oxalic acid and its radiolysis products.

Hydrogenation of benzene on technetium catalysts

Conclusions1.The specific activity of technetium on various supports in the hydrogenation of benzene is only slightly dependent on the nature of the support.2.Catalysts containing technetium are more active than those containing rhenium.

Influence of nature of support on properties of technetium catalysts

Conclusions1.The influence of the nature of the support on the catalytic activity of technetium has been established for reactions of cyclohexane and isopropanol dehydrogenation. The most active are Tc/MgO and Tc/REE oxides; the least active are Tc/SiO2, Tc/C, and Tc/TiO2.2.Temperature-programmed reduction of the system consisting of ammonium pertechnetate and a support has shown that SiO2 plays the role of a dispersing agent, whereas Y2O3 and γ-Al2O3 interact with the NH4TcO4.3.When CO is adsorbed on Tc γ-Al2O3 or Tc/Y2O3, linear and bridge surface structures are formed. On Tc/MgO, in addition to these structures, multicenter carbonyl structures are found.4.An examination of diffuse reflection spectra in all stages of catalyst preparation has shown that in the most active catalysts, an ionic species of technetium is preserved along with metallic technetium; this ionic species has a modifying effect on the processes of alcohol and cyclohexane dehydrogenation.