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The Characterization of Modified Higher Aliphatic Alcohols-Synthesis Catalysts by EPR and XPS Methods

Skrzypek D., Krupa K., Winiarski A., Szymanska B.

Polish Journal of Chemistry

2005

Vol. 79 / nr 1

145-153

Aseries of copper-zinc catalysts for aliphatic alcohols synthesis with a varying amount of additives was prepared by thermal decomposition of metal citrates. The results of catalytic experiments, made in a laboratory high-pressure reactor, showed a good stability and almost constant activity and selectivity during 4 months. In this paper the catalyst before (A) and after (B) reaction is characterized by EPR and X-ray photoelectron spectroscopies. For catalystAthe copper species were identified as isolated Cu2+ ions in a dynamic Jahn-Teller configuration. For the sample B the EPR spectrum is complex and its features are corresponding to: clustered Cu2+ species with dipole-dipole interaction; Fe3+ ions in rhombically distorted symmetry; O2- centres.

Methanol Synthesis from CO2 and H2 on Cu/ZnO/Al2O3-ZrO2 Catalysts. Catalytic Activity and Adsorption of Reactants

Słoczyński J., Grabowski R., Kozłowska A., Lachowska M., Skrzypek J.

Polish Journal of Chemistry

2001

Vol. 75, nr 5

733-742

Effect of preparation method and substitution of Al2O3 by ZrO2 on the adsorption of CO, CO2, H2O and methanol on the Cu/ZnO/Al2O3 - ZrO2 catalysts as well as their activity in the synthesis of methanol from CO2 and H2 were investigated. The catalytic activity increases in the series: Cu/ZnO/Al2O3 obtained by co-precipitation < Cu/ZnO/Al2O3 < Cu/ZnO/Al2O3 - ZrO2 obtained by the amorphous precursor (citric acid) method < Cu/ZnO/ZrO2 obtained by the amorphous precursor (citric acid) method. It has been found that catalysts obtained by using citric acid as complexing agent show higher adsorption of methanol compared to water than the catalysts obtained by the coprecipitation. A partial substitution of Al2O3 by ZrO2 evidently decreases the reversible adsorption of water and CO. A correlation between adsorptive and catalytic properties has been established.With increasing ratio of reversibleCO2/CO orCH3OH/H2Oadsorption, an increase of the catalysts activity in the synthesis of methanol from CO2 and H2 is observed.