N2O decomposition over K/Na-promoted Mg/Zn–Ce–cobalt mixed oxides catalysts.

Three groups of cobalt mixed oxide catalysts (Mg/Zn–Co, Mg/Zn–Ce–C, K/Na–Mg/Zn–Ce–Co) were prepared by sol–gel or impregnation methods. The synergistic effects of transition metal, rare earth metal and alkali metal on cobalt mixed catalysts for nitrous oxide (N 2 O) decomposing to N 2 and O 2 were investigated. The experimental results revealed that the catalytic activity for N 2 O decomposition was promoted as Co 2 + was replaced partially by Zn 2 + /Mg 2 + , moreover, the characterization analysis by XRD and XPS showed that Zn 2 + /Mg 2 + replaced Co 2 + successfully into the spinel structure of Co 3 O 4 and promoted significantly the catalytic activity. Especially, the addition of CeO 2 and K 2 O/Na 2 O decreased the binding energy and resulted in an increase in the density of the electron cloud around Co and an improvement of the catalytic activity. Of the investigated cobalt mixed catalysts, the best catalytic activity was shown by 2% K–Zn0.5–Ce0.05–Co catalyst. [ABSTRACT FROM AUTHOR]