Optimization of Cs content in Co–Mn–Al mixed oxide as catalyst for N2O decomposition
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A series of Co–Mn–Al mixed oxide catalysts with different Cs contents (0.5–4.6 wt%) was prepared by calcination of Co–Mn–Al hydrotalcite (Co:Mn:Al = 4:1:1), followed by impregnation by cesium salt (CsNO3, Cs2CO3) using the pore filling method. Chemical analysis, N2 sorption, temperature programmed reduction (TPR)-H2, temperature programmed desorption (TPD)-CO2 and TPD-NH3 and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. All prepared catalysts were tested for N2O catalytic decomposition in inert gas and in the presence of oxygen, water vapor and nitric oxide. The influence of Cs salts used for catalyst preparation and cesium content on catalyst activity were studied. A significant increase in catalytic activity with increasing amount of cesium promoter was observed without respect to the Cs precursor. The strong promotional effect of cesium is electronic in nature and is discussed in term of changes in surface composition and catalyst reducibility.
KeywordsNitrous oxide Catalytic decomposition Mixed oxide catalysts Cesium promoter Layered double hydroxides
This work was supported by the Czech Science Foundation (Project No. 14-13750S) and by the Ministry of Education, Youth and Sports of the Czech Republic in the “National Feasibility Program I,” project LO1208 “Theoretical Aspects of Energetic Treatment of Waste and Environment Protection against Negative Impacts” and by the specific research projects SP2014/48, SP2014/62 and SP2015/125.