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3 Polish Journal of Chemistry

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The Effect of Potassium on Ni/Al2O3 Catalysts for CO/H2 Reaction

Znak L., Zieliński J.

Polish Journal of Chemistry

2009

Vol. 83, nr 10

1797-1807

The effect of potassium on Ni/Al2O3 catalyst in relation to CO/H2 reaction was studied. XRD examinations and extensive adsorption measurements (H2, O2 and CO) have shown a small effect on nickel dispersion. At the same time the measurements of thermal effect revealed that potassium decreases heat of O2 adsorption and increase heat of CO adsorption, which proves that the promoter is located on nickel surface. Temperature-programmed studies showed that potassium significantly retards hydrogenation of pre-adsorbed CO and this result was confirmed by steady state examination of CO/H2 reaction.

Adsorption of Hydrogen on Unsupported and Supported Nickel

Znak L., Zieliński J.

Polish Journal of Chemistry

2004

Vol.78 /nr 11-12

2197-2203

The interaction of hydrogen with Ni powder and supported nickel catalysts was studied by temperature-programmed desorption (TPD) method. The measurements of hydrogen desorption were started at about 100 K, which resulted in formation of extended spectra of hydrogen chemisorbed on nickel. Preliminary examinations of the spectra indicate that at low temperature considerable quantity of hydrogen is located in subsurface region of nickel. Quantitative analysis of the spectra recorded for Ni powder showed that at low temperature the stoichiometry of hydrogen chemisorption on nickel, i.e. H/Nis ratio, is close to 1.8. The studies of hydrogen adsorption on supported nickel catalysts indicate that commonly applied measurements of hydrogen adsorption at room temperature are justified for characterization of Ni/Al2O3, but appear inappropriate for Ni/SiO2

Chemical Characterization of a Fused Iron Catalyst for Ammonia Synthesis

Zieliński J., Znak L., Kowalczyk Z.

Polish Journal of Chemistry

2001

Vol. 75, nr 12

1927-1933

A triply promoted fused iron catalyst was examined by (i) temperature-programmed desorption of hydrogen, (ii) temperature-programmed desorption of nitrogen, (iii) temperature-programmed hydrogenation of preadsorbed nitrogen and (iv) chemisorption of carbon monoxide. The studies demonstrate that all the methods arę suitable for characterization of the catalyst, provided that the experimental conditions of the measurements are correctly chosen.