The deactivation effect of Na2O and NaCl on CeO2–TiO2 catalysts for selective catalytic reduction of NO with NH3

Abstract

The effect of Na2O and NaCl on CeO2–TiO2 catalyst for the selective catalytic reduction of NO with NH3 was investigated with BET, XRD, XPS, NH3-TPD, H2-TPR, in-situ DRIFT and catalytic activity measurements. The results showed that both Na species could deactivate the CeO2–TiO2 catalyst and Na2O had a stronger effect than NaCl. The more serious deactivation by Na2O could be ascribed to smaller surface area, fewer surface Ce3+ and chemical adsorbed oxygen, lower surface acidity, and worse reducibility. The introduction of NaCl and Na2O facilitated the formation of new surface NOx adspecies, but were inactive in NH3-SCR reaction. The adsorption of NH3 were inhibited. The NH3-SCR reaction over the CeO2–TiO2 catalyst was governed by both E-R and L-H mechanisms. The introduction of NaCl and Na2O didn't change the NH3-SCR reaction mechanisms.