Effect of the preparation method on high-temperature de-N2O performance of Na-CaO catalysts. A mechanistic study

A simple cellulose-templating (CT) method was used to prepare Na-CaO catalysts for high-temperature N2O decomposition to N-2 and O-2 in excess of NO, O-2, and H2O. According to this method, cellulose materials were soaked in aqueous solution of calcium and/or sodium nitrates followed by burning out the template material. Depending on the nature of cellulose template and calcination procedure, the obtained catalysts consisted of regularly shaped particles of 100-400 nm. Conventionally prepared Na-CaO reference materials had randomly shaped particles on a micron scale. Compared to the latter catalysts, the CT ones showed higher de-N2O activity and resistance against inhibition by NO and O-2, which make them interesting from industrial point of view. Transient analysis of NO interaction with the studied catalysts in the presence and the absence of O-2 enabled us to conclude that the superior de-N2O performance of the CT materials is due to improved desorption of surface NOx species acting as inhibitors for N2O decomposition. (C) 2010 Elsevier B.V. All rights reserved.