Effects of Na+ on Cu/SAPO-34 for ammonia selective catalytic reduction
Can Wang , Chen Wang , Jun Wang , Jianqiang Wang , Meiqing Shen , Wei Li
DOI:10.1016/j.jes.2017.11.002
Received July 24, 2017,Revised , Accepted November 02, 2017, Available online November 14, 2017
Volume 30,2018,Pages 20-28
Copper-exchanged chabazite (Cu/CHA) catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na+ ions on Cu/SAPO-34 for ammonia selective catalytic reduction (NH3-SCR) are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na+ ion-exchanges with H+ and Cu2 + of Cu/SAPO-34. The exchange of H+ is easier than that of isolated Cu2 +. The exchanged Cu2 + ions aggregate and form “CuAl2O4-like” species. The NH3-SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu2 + and acid sites is responsible for the activity loss.
