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 N2 and O2 in excess of NO, O2, 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 O2, 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 O2 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.

Figure optionsDownload as PowerPoint slideResearch highlights▶ De-N2O activity of Na-promoted CaO catalysts and, most important, their resistance against inhibition by NO–O2 are determined by the method of catalyst preparation. ▶ Application of cellulose templates (CT) for catalyst preparation opens possibilities for particle size tuning. ▶ Smaller particles afford improved de-N2O performance. ▶ Superior de-N2O performance of the CT materials is due to improved desorption of surface NOx species acting as inhibitors for N2O decomposition.