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The hydrogenation of a mixture of alkylsubstituted C7—C12 benzene compounds was studied. The aim of this reaction was to obtain a high-density liquid fuel that could be used as a liquid organic carrier of hydrogen. The results of the reaction carried out on a supported Pd/Al2O3 catalyst indicated that the structures of substituted substrates and the composition of side ring-opening reaction products had a significant effect on the hydrogen capacity of the hydrogenation products. [ABSTRACT FROM AUTHOR]

Density functional theory calculations (DFT) were performed to investigate the Fe-facet effect on the CO2 potential barrier as well as trajectory of CO2 adsorption. It was found that potential barrier of CO2 adsorption on Fe (111) is almost absent (~0.01 eV). At the same time, potential barriers of CO2 adsorption on Fe (100) and Fe (110) are 0.10 and 0.26 eV, correspondingly. The most stable configuration of CO2 adsorption on different Fe facets under consideration is CO2 adsorbed on Fe (111) with heat effect –1.16 eV, whereas adsorption energies of CO2 on Fe (100) and Fe (110) are –0.87 and –0.15 eV, correspondingly. Found values are in good agreement with literature data. Most energetically favorable trajectory of the CO2 adsorption passes through 2-fold adsorption site (located near two neighbor Fe atoms) in case of flat Fe facets (100) and (110). Unexpectable tend to spontaneous dissociation of CO2 molecule on desorption stage was found at distance ~2.66 Å above Fe (100) surface. Analysis of electron spin distributions allows one to conclude that dissociation is caused by excitation of CO2 molecule accompanied with rearrangement of the spin density of the both CO2 molecule and surface Fe (100) atoms rather than charge transfer. CO2 dissociation on adsorption stage on Fe (100) facet was not found as well as it was not observed over other Fe facets both on desorption and on adsorption stages. [ABSTRACT FROM AUTHOR]

A correlation of the reaction rate over Fe-Beta catalysts with a concentration of specific isolated Fe3+ sites represented by an ESR signal at g ≈ 4.3 and by UV adsorption bands with λmax < 300 nm was observed. Blocking zeolite cationic positions with Ca2+ and investigation of “Fe-free” Beta-zeolites confirmed the idea of isolated Fe complexes in cationic positions being active sites for NH3-deNOx. [ABSTRACT FROM AUTHOR]

Pt/Al2O3 and Pt/BaO/Al2O3 catalysts (1 wt% Pt, 10 wt%BaO) were sulfated under conditions simulating a real NSR catalyst operation. Comparative TPR and XPS studies of sulfur removal from Pt/Al2O3 and Pt/BaO/Al2O3 catalysts indicate that the sulfur removal from Al2O3 surface precedes reductive decomposition of BaSO4 (250–400 °C). Barium sulfate decomposition started with further increase in desulfation temperature at the point of surface atomic ratio Ba:S = 1 (~450o). Simultaneously, an intensive formation of sulfide species on the catalyst surface was observed. Thermodynamic analysis of the desulfation process allows us to hypothesize that barium sulfide formation may hinder sulfur removal under reducing conditions. [ABSTRACT FROM AUTHOR]

Possible mechanisms are suggested for propane oxidation on Pt/TiO2/Al2O3 and Pt/CeO2/Al2O3 catalysts in the cyclic reactant supply mode. As compared to the steady-state process, the process conducted as catalyst oxidation-reduction cycles results in a very different product composition: it is more selective toward partial oxidation products and yields much smaller amounts of complete oxidation products. It is established by isothermal and temperature-programmed oxygen desorption that, under the reaction conditions examined, the oxygen desorbed from the catalyst surface into the gas phase makes a negligible contribution to propane oxidation. It is proved by XPS that propane oxidation is due to the chemically bound oxygen of the catalyst. The hypothetical mechanism of the process includes propane activation on Pt followed by the transfer of the activated species to the oxygen-storing component (TiO2 or CeO2), where the intermediates are oxidized by chemically bound oxygen. [ABSTRACT FROM AUTHOR]

The oxygen storage capacity of 1% Pt/15% MxOy/Al2O3 systems containing a rare-earth or an alkaline-earth metal oxide or TiO2 as the oxygen-storing component was studied. Oxygen storage capacity was evaluated as the amount of C3H8 reacting at 400°C with oxygen that was taken up by the catalyst during oxidative treatment. The systems containing a rare-earth metal oxide or TiO2 possess the highest oxygen storage capacity among the catalysts examined (80 and 75 µmol C3H8/g Cat, respectively). Of the BaO and SrO systems, the latter is of interest, although its oxygen storage capacity (∼27 µmol C3H8/g Cat) is somewhat lower than the oxygen storage capacity of any rare-earth metal oxide or the TiO2 system. [ABSTRACT FROM AUTHOR]

A correlation of the reaction rate over Fe-Beta catalysts with a concentration of specific isolated Fe3+ sites represented by an ESR signal at g ≈ 4.3 and by UV adsorption bands with λmax < 300 nm was observed. Blocking zeolite cationic positions with Ca2+ and investigation of “Fe-free” Beta-zeolites confirmed the idea of isolated Fe complexes in cationic positions being active sites for NH3-deNOx. [ABSTRACT FROM AUTHOR]

The number dynamics of Bradyrhizobium japonicum strain 646a introduced into soil in the soybean, common bean and maize rhizosphere and its dependence on inoculum doses have been studied in greenhouse experiments. It was shown that B. japonicum number in the maize, common bean and soybean rhizosphere depends on the inoculum doses (r = 0.79-0.95). It was less than 0.1% of total saprophytic bacteria number and it had no essential effect on this plant productivity. The soybean symbiosis with nodule bacteria enhanced its yield by 28.9-42.6%. In nodulating soybean rhizosphere B. japonicum reproduced most intensively and reached the maximum number 52-225 thousand bacteria/g of soil in the period of soybean maturing and nodule destruction. This indicated to important role of soybean nodules not only in symbiotic nitrogen fixation, but also in formation of the rhizosphere and soil B. japonicum population.