Chislova, I. V.

Dementieva, M. V.

Serov, Y. M.

Sheshko, T. F.

Shulga, A.

Zvereva, I. A.

BSU Digital Library

 48 
CATALYSIS, PHOTOCATALYSIS 
The application of perovskite-type ferrites  
in the catalytic hydrogenation of carbon monooxide 
T. F. Sheshko1,  Y. M. Serov1, M. V. Dementieva1, A. Shulga1, I. V. Chislova2, I. A. Zvereva2 
1Peoples Friendship University of Russia, Moscow, Russia 
2Saint-Petersburg State University, Saint-Petersburg, Russia 
e-mail:  sheshko@bk.ru 
  Studied in this paper layered oxides and solid solutions were synthesized by the high temperature 
solid- state reactions and by sol-gel technology. Among synthesized ferrites there are three-
dimensional perovskites GdFeO3, SrFeO3+x, and two-dimensional perovskite-type layered structures 
GdSrFeO4, Gd2SrFe2O7, Gd2‒xSr1+xFe2O7 (x = 0.1‒0.6), belonging to Ruddlesden‒Popper phases 
An+1BnO3n+1 (n = 1.2) that are built up from  the blocks of perovskite layers with different thickness.  
X-ray powder diffraction confirmed the presence of single phase for samples obtained both by high 
temperature solid state reactions and by sol-gel technology as well.  Scanning electron microscopy 
demonstrated a decrease in size of complex ferrite particles from 10 μm, obtained by ceramic tech-
nology, up to 200 nm, obtained by the sol-gel technology. Mössbauer spectroscopy showed the dif-
ference of electronic state of complex ferrite, prepared by ceramic technology (Fe+3) and oxides ob-
tained by sol-gel technology (Fe+3 in the three different surrounding and Fe+4). 
  Reaction products of carbon monooxide hydrogenation are hydrocarbons C1 ‒ C5, the main of 
them are methane, ethylene, propylene. The greatest amount of olefins formed in the reaction was 
observed at the stoichiometric CO : H2 ratio. It was found that perovskite catalytic activity (rate of 
product formation) in the catalytic hydrogenation of carbon monooxide increases in the series: 
SrFeO3‒x < GdSrFeO4 < Gd1.6Sr1.4Fe2O7 < Gd1.8Sr1.2Fe2O7 < Gd2SrFe2O7 < GdFeO3, that is in correla-
tion with the number of alternating perovskite layers in the ferrites structure varying from 1, 2 to ∞. 
However, samples with n = 2 showed the highest selectivity for ethylene and propylene (Fig). 
 
 
Fig. Total olefin selectivity during the reaction in a ratio of СО : Н2 = 1 : 2 
The increase in strontium content in the layered Gd2‒xSr1+xFe2O7 oxides to x = 0.6 decreases the 
symmetry of Fe+3 ions and increases the number of oxygen vacancies, which affect the selectivity (its 
maximum value was observed at x = 0.3). It was suggested that heterovalent state of iron (Fe3+, Fe4+) 
favors the CO activation, which leads to C∙ and CHx
∙ radicals formation. It was shown that under the 
influence of the reaction medium and the temperature a change in the active centers state occurs. 
Probably this change consists in partial iron reduction. 
 Higher catalytic performance of perovskite-like ferrites synthesized by sol-gel method can be 
related to their nanocrystalline state with a porous structure, as well as to iron heterovalent state.  
Acknowledgment. This work was supported by the Russian Foundation for Basic Research 
(№ 14-03-00940). 


The application of perovskite-type ferrites  in the catalytic hydrogenation of carbon monooxide

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The application of perovskite-type ferrites in the catalytic hydrogenation of carbon monooxide

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