• Larisa Lutsenko Taras Shevchenko National University of Kyiv, Ukraine
  • Luidmila Oleksenko Taras Shevchenko National University of Kyiv, Ukraine
  • Olexandr Ripko Taras Shevchenko National University of Kyiv, Ukraine
  • Inna Vasylenko L. V. Pysarzhevsky Institute of Physical Chemistry, National Academy of Sciences of Ukraine, Ukraine




citrate method, Co3O4, CeO2, catalysts, CO oxidation


The article deals with obtaining of highly dispersed oxide materials on the base of cobalt and cerium and their catalytic activity for CO oxidation. Іndividual cobalt and cerium oxides and binary oxides with Co:Ce molar ratio 1:1 were synthesized by citrate method. The temperature intervals of formation of Co,Ce-citrates, their decomposition to citraconates and decomposition of citraconates resulting to formation of oxides were found by differential thermal analysis. Phase compositions, specific surface areas and catalytic performances towards CO oxidation for the synthesized individual oxides and binary oxide systems were investigated. By XRD analysis it was established that cobalt and cerium oxide materials were obtained as highly dispersed Co3O4 with spinel structure and CeO2 with fluorite structure. Average crystallite sizes in the individual oxides were 36 and 15 nm for Co3O4 and CeO2, respectively. In the case of the binary oxides a decrease of the crystallite sizes to 13 nm (Co3O4) and 3–4 nm (CeO2) was shown. Higher specific surface area values of the binary oxide materials as compared with these values for the individual oxides agrees with XRD data assuming a formation of cobalt and cerium oxide particles with smaller sizes. Higher dispersion of the binary oxide systems is realized probably due to stabilization of Co3O4 and CeO2 particles of small sizes because of their interaction during oxide preparation and as a result formation of interface between them. A catalytic activity study shown that binary Co3O4–CeO2 system with metal ratio Co : Ce = 10 : 1 has demonstrated the highest activity – temperature of CO complete conversion was 148 °C. As a reason of this high catalytic activity, in addition of well-dispersed oxide state, may be formation of active mobile oxygen at the interface between Co3O4 and CeO2 particles.


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Physical and inorganic chemistry