Optimization of cesium and potassium promoter loading in alkali-doped Zn0.4Co2.6O4|Al2O3 catalysts for N2O abatement

• Published in: Reaction kinetics, mechanisms and catalysis Vol. 121; no. 2; pp. 645 - 655
• Main Authors: Ciura, Klaudia, Grzybek, Gabriela, Wójcik, Sylwia, Indyka, Paulina, Kotarba, Andrzej, Sojka, Zbigniew
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2017
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Physical Chemistry; Decomposition of nitrous oxide; Alkali promotion; Co; Supported catalyst; Cobalt spinel; O
• ISSN: 1878-5190; 1878-5204
• DOI: 10.1007/s11144-017-1188-9

A series of potassium or cesium doped Zn 0.4 Co 2.6 O 4 |Al 2 O 3 catalysts with different alkali loadings were prepared, characterized with respect to chemical composition (XRF), structure (XRD, RS) morphology (TEM), and the alkali promoter thermal stability. A strong beneficial effect on the deN 2 O activity of the Zn 0.4 Co 2.6 O 4 |Al 2 O 3 catalyst (decrease in the T 50% by about 80 °C) was observed for both promoters at different surface coverages. It was found that in comparison to a rather narrow range of optimal cesium loading (0.5–2 atoms/nm 2 ) a comparable promotional effect of potassium doping was observed for a slightly wider surface concentrations (0.5–3 atoms/nm 2 ). Such difference was attributed to surface dispersion of potassium over the alumina support and the spinel active phase, while cesium was found to be located mainly on the spinel phase. For practical applications, the superiority of potassium over cesium consist in fact that a similar beneficial effect is associated with much higher thermal stability in the temperature range of the catalyst deN 2 O operation and lower price of the promoter precursor.