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The effect of iron nanocrystallites’ size in catalysts for ammonia synthesis on nitriding reaction and catalytic ammonia decomposition

100%

Pelka R. , Kiełbasa K. , Arabczyk W.

Open Chemistry

2011

tom 9

nr 2

240-244

Iron catalyst for ammonia synthesis of various mean sizes of iron nanocrystallites were nitrided with ammonia in a differential reactor equipped with systems that made it possible to conduct both thermogravimetric measurements and hydrogen concentration analyses in the reacting gas mixture. The nitriding process was investigated under atmospheric pressure at the temperature of 475°C. It was found that along with an increase of mean size of iron nanocrystallites, with a decrease of specific surface area of the samples, nitriding degree of solid samples increased. At the same time the rate of surface reaction of catalytic ammonia decomposition decreased. Along with an increase of the samples’ specific surface area an increase of the catalyst’s activity was observed. However, it was also observed that the concentration of active sites on the catalysts’ surface decreased along with an increase of specific surface area.

Characterization of FeCo based catalyst for ammonia decomposition. The effect of potassium oxide

100%

Lendzion-Bieluń Z. , Pelka R. , Czekajło Ł.

Polish Journal of Chemical Technology

2014

tom 16

nr 4

111-116

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.

The possibility of implementation of spent iron catalyst for ammonia synthesis

100%

Ekiert E. , Pelka R. , Lubkowski K. , Arabczyk W.

Polish Journal of Chemical Technology

2009

tom 11

nr 1

28-33

An iron catalyst used in the ammonia synthesis is pyrophoric in its reactive, reduced form. Before further use the catalyst has to be passivated. Results of the research on the iron catalyst - its passivation, re-use as a catalyst in other processes and implementation as a substrate to obtain new nanocrystalline materials have been presented in the paper.

Utilization of spent iron catalyst for ammonia synthesis

51%

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

2007

tom 9

nr 3

108-113

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.