The promotion effect of Fe to Cu-SAPO-34 for selective catalytic reduction of NOx with NH3

• Published in: Catalysis today Vol. 297; pp. 84 - 91
• Main Authors: Zhao, Huawang, Li, Huisheng, Li, Xianghui, Liu, Mengke, Li, Yongdan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2017
• Subjects: Cu-SAPO-34; Fe modification; Isolated Cu2+ ions; NH3-SCR; NOx conversion; Isolated Cu2+ ions; NOx conversion; NH3-SCR; Cu-SAPO-34; Fe modification
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2017.05.060

[Display omitted] •1wt.% Fe loaded Cu-SAPO-34 shows enhanced SCR performance above 200°C.•1wt.% Fe loading by impregnation method produces more isolated Cu2+ ions.•The addition of 1wt.% Fe decreases the amount of surface bulk CuO species.•The addition of 1wt.% Fe suppresses the NH3 oxidation activity.•The isolated Fe3+ ions in Cu-SAPO-34 sample are additional active sites. A number of Fe loaded Cu-SAPO-34 (Fe: Cu-SAPO–34=0.5, 1 and 1.5wt.%) catalysts were prepared with incipient wetness impregnation of iron acetate solution on a one-pot synthesized Cu-SAPO-34 sample. The Fe/Cu-SAPO-34 sample with 1wt.% Fe loading shows the best selective catalytic reduction performance among the samples tested at temperatures above 200°C. The results of ultraviolet-visible diffuse reflectance spectroscopy indicate that isolated Fe3+ ions, FexOy oligomers, and Fe2O3 particles coexist in the Fe incorporated samples. Further examinations tell that the bulk CuO on the surface in the Cu-SAPO-34 sample with appropriate amount of Fe addition transforms to isolated Cu2+ ions, which enhances its catalytic activity in the temperature range of 200–350°C. The Fe: Cu-SAPO–34=1wt.% sample exhibits a lower NH3 oxidation ability at high temperatures than that of Cu-SAPO-34, which is due to the reduced amount of bulk CuO species on the surface. Both the reduced NH3 oxidation ability and the additional isolated Fe3+ sites contribute to the excellent activity of the Fe: Cu-SAPO-34=1wt.% sample above 350°C.