Authors:T. Yusupova, L. Petrova, R. Mukhametshin, G. Romanov, T. Foss and Yu. Ganeeva
The core samples of oil- and bitumen-containing rocks from Tatarstan's deposits of different ages were studied by thermal
analysis methods (DTA, TG, DTG). Based on the obtained data, a procedure was elaborated for determining the enclosed organic
matter content and the index of its fraction composition.
A significant increase of the organic matter content in the core and its enrichment in high-molecular aromatic structures
were shown to occur for the oil-containing rock samples when passing from the Devonian to Carboniferous and Permian deposits.
The core samples of the Devonian oil-containing rocks may be divided into three groups: the samples taken from the zones where
waste water flooding has been started relatively recently (1), or fresh water flooding has been carried on for a long time
(2) and the samples of rock containing clay minerals as impurities. Thus, thermal analysis can be used in geochemical studies
to identify the organic matter enclosed by oil- and bitumen-containing rocks.
Authors:Viorel Chihaia, Karl Sohlberg, L. Ilieva, P. Petrova, T. Tabakova, R. Zanella and Z. Kaszkur
Gold catalysts supported on ceria doped with different metal oxides (Fe, Mn, Co and Sn) were synthesized using two techniques: CP and mechanochemical activation. The catalytic activity in complete benzene oxidation (CBO) was studied. The samples were characterized by means of XRD and high resolution transmission electron microscopy, and non-significant differences in the average size and the distribution of gold particles were observed. This means that the main reason for the different catalytic behavior in CBO has to be searched in the composition and structure of the supports. In spite of the higher hydrogen consumption (e.g., higher oxygen mobility) estimated by means of TPR, the gold catalysts on ceria doped with transition metal oxides generally are less active than gold/ceria catalyst. This observation could be explained taking into consideration that the key factor for the high oxidation activity is not the oxygen supplying but the activation of the very stable benzene molecule. The higher catalytic activity in comparison with that of the gold/ceria catalyst was observed only using a mixed ceria–CoOx support mechanochemically prepared. Very high and stable catalytic activity in CBO was obtained over this sample.
Authors:L. Ilieva, G. Munteanu, P. Petrova, T. Tabakova, N. Velinov and I. Mitov
Gold catalysts supported on ceria doped with FeOx were studied. The mixed supports were synthesized by two methods: co-precipitation (CP) or mechanochemical activation (MA). Depending on the preparation method, the structure of the mixed supports was different: using CP, only a Fe-modified ceria phase exists, while supplementary to ceria, a second hematite phase presents in the case of MA preparation. The reduction behavior of the gold catalysts and the initial supports was commented on the basis of hydrogen consumption and kinetic parameters of the individual reduction process. Their assignment was proposed using also the data of Mössbauer measurements. It was established that the existing separate Fe-containing phase could participate in a redox process at relatively low temperatures (LTs) and it could be promising for improvement of the catalytic performance of the mechanochemically prepared gold catalyst.