Enhanced hydrothermal stability of Cu-SSZ-13 catalysts with phosphorus modification

Yongdan  Li, Tianjin University and Aalto University

Enhanced hydrothermal stability of Cu-SSZ-13 catalysts with phosphorus modification

 

Huawang Zhao^a, Yongdan Li^a,b

 

^a, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin Key Laboratory of Applied Catalysis Science and Technology, State Key Laboratory of Chemical Engineering (Tianjin University), School of Chemical Engineering, Tianjin University, Tianjin 300072, China

b, Aalto University, School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, Kemistintie 1, Espoo, P.O. Box 16100, FI-00076 Aalto, Finland

Tel.: +86 22 27405613; Fax: +86 22 27405234. E–mail address: ydli@tju.edu.cn (Y.D. Li).

 

 

Abstract: A number of phosphorus-loaded Cu-SSZ-13 catalysts were prepared in this work. The addition of phosphorus disrupts the structure of Cu-SSZ-13, forming extra-framework Al phosphate species, thus leading to a decrease of the activity in low-temperature range. However, after hydrothermal aging at 750 ^oC for 16 h, the bare Cu-SSZ-13 lost the selective catalytic reduction (SCR) catalytic activity, while the overall activity of the phosphorus modified samples was retained or even improved with the high phosphorus content sample. During the hydrothermal aging, the framework of Cu-SSZ-13 sample without phosphorus collapsed completely, while the damages of the structure of the phosphorus modified samples was minor. The phosphate species in the modified samples migrated to the defects induced by the dealumination in the zeolite framework, forming silicoaluminophosphate interface, which kept the framework stable during the aging process. This result indicates that the phosphorus in diesel, especially in biofuel, may not need to be removed completely.