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The effect of manganese on the structural and surface properties of nanocrystalline cobalt catalyst for ammonia synthesis

100%
Lendzion-Bieluń Z.
Open Chemistry
|
2012
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vol. 10
|
issue 2
327-331
EN
Based on the active surface model of the iron catalyst for ammonia synthesis, the assumptions which led to obtaining the cobalt catalyst for ammonia synthesis were described. The incorporation into the system small amounts of manganese, an element which binds oxygen stronger than cobalt, has influence the development of the catalyst’s specific surface area. The activity of manganese modified catalysts is higher than that of cobalt catalyst without manganese addition. The obtained catalysts were characterized with the following methods: ICP-OES, XRD, BET [...]
2
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Determination of the Content of Promoters in Magnetite and Wustite Phases in the Fused Iron Catalyst

63%
Lendzion-Bieluń Z., Jędrzejewski R.
Polish Journal of Chemical Technology
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2013
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vol. 15
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issue 1
27-29
EN
Taking advantage of differences in etching rates of crystallographic phases, forming an oxidized form of the fused iron catalyst, a content of promoters in main phases, magnetite and wustite, was determined. A calcium oxide content in magnetite and wustite was 0.54 wt% and 3.59 wt%, respectively. Aluminum oxide was found in the magnetite phase, and its content was 4.5 wt%. The third promoter, potassium oxide, was almost completely located outside these phases. XRD and ICP-OES instrumental methods were used in the investigations.
3
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Studies on the recrystalization of nanocrystalline metals

63%
Lendzion-Bieluń Z., Gleń M.
Polish Journal of Chemical Technology
|
2007
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vol. 9
|
issue 4
5-7
EN
The influence of the promoters such as CaO, Al2O3 and K2O on the specific surface area of the nanocrystalline cobalt was determined. The recrystalization process of the nanocrystalline cobalt was determined and compared with the examinations conducted on the iron catalyst for ammonia synthesis. The triply promoted nanocrystalline obtained cobalt after the annealing process, has got greater specific surface area than the triply promoted iron.
4
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Characterization of FeCo based catalyst for ammonia decomposition. The effect of potassium oxide

51%
Lendzion-Bieluń Z., Pelka R., Czekajło Ł.
Polish Journal of Chemical Technology
|
2014
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vol. 16
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issue 4
111-116
EN
FeCo fused catalyst was obtained by fusing iron and cobalt oxides with an addition of calcium, aluminium, and potassium oxides (CaO, Al2O3, K2O). An additional amount of potassium oxide was inserted by wet impregnation. Chemical composition of the prepared catalysts was determined with an aid of the XRF method. On the basis of XRD analysis it was found that cobalt was built into the structure of magnetite and solid solution of CoFe2O4 was formed. An increase in potassium content develops surface area of the reduced form of the catalyst, number of adsorption sites for hydrogen, and the ammonia decomposition rate. The nitriding process of the catalyst slows down the ammonia decomposition.
5
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The effect of aluminium oxide on the reduction of cobalt oxide and thermostabillity of cobalt and cobalt oxide

51%
Lendzion-Bieluń Z., Jędrzejewski R., Arabczyk W.
Open Chemistry
|
2011
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vol. 9
|
issue 5
834-839
EN
During precipitation and calcination at 200°C nanocrystalline Co3O4 was obtained with average size crystallites of 13 nm and a well developed specific surface area of 44 m2 g−1. A small addition of a structural promoter, e.g. Al2O3, increases the specific surface area of the cobalt oxide (54 m2 g−1) and decreases the average size of crystallites (7 nm). Al2O3 inhibits the reduction process of Co3O4 by hydrogen. Reduction of cobalt oxide with aluminium oxide addition runs by equilibrium state at all the respective temperatures. The apparent activation energy of the recrystallization process of the nanocrystalline cobalt promoted by the aluminium oxide is 85 kJ mol−1. Aluminium oxide improves the thermostability of both cobalt oxide and the cobalt obtained as a result of oxide phase reduction. [...]
6
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Utilization of spent iron catalyst for ammonia synthesis

27%
Arabczyk W., Narkiewicz U., Lendzion-Bieluń Z., Moszyński D., Pełech I., Ekiert E., Podsiadły M., Pelka R., Jędrzejewski R., Moszyńska I., Sibera D.
Polish Journal of Chemical Technology
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2007
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vol. 9
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issue 3
108-113
EN
Several methods of the utilization of spent iron catalyst for ammonia synthesis have been presented. The formation of iron nitrides of different stoichiometry by direct nitriding in ammonia in the range of temperatures between 350°C and 450°C has been shown. The preparation methods of carbon nanotubes and nanofibers where iron catalyst catalyse the decomposition of hydrocarbons have been described. The formation of magnetite embedded in a carbon material by direct oxidation of carburized iron catalyst has been also presented.
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