Effect of preparation methods on the performance of CuFe-SSZ-13 catalysts for selective catalytic reduction of NOx with NH3

Yijiao Wang; Lijuan Xie; Fudong Liu; Wenquan Ruan

doi:10.1016/j.jes.2019.01.013

Effect of preparation methods on the performance of CuFe-SSZ-13 catalysts for selective catalytic reduction of NO_x with NH₃

J Environ Sci (China). 2019 Jul:81:195-204. doi: 10.1016/j.jes.2019.01.013. Epub 2019 Jan 31.

Authors

Yijiao Wang¹, Lijuan Xie¹, Fudong Liu², Wenquan Ruan³

Affiliations

¹ School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China.
² Department of Civil, Environmental, and Construction Engineering, Energy Conversion and Propulsion Cluster, University of Central Florida, Orlando, FL 32816, United States.
³ School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China. Electronic address: wqruan@jiangnan.edu.cn.

PMID: 30975322
DOI: 10.1016/j.jes.2019.01.013

Abstract

CuFe-SSZ-13 catalyst showed excellent performance in the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) for diesel engine exhaust purification. To investigate the effect of preparation methods on NH₃-SCR performance, Fe was loaded into one-pot synthesized Cu-SSZ-13 catalysts through solid-state ion-exchange (SSIE), homogeneous deposition precipitation (HDP) and liquid ion-exchange (IE), respectively. Three CuFe-SSZ-13 catalysts showed similar SO₂ resistance, which was better than that of Cu-SSZ-13. The improvement was attributed to the protection of Fe species. Hydrothermal stability of three CuFe-SSZ-13 catalysts was significantly different, which was attributed to the state of active species caused by different preparation methods. Compared with the other two catalysts, more active species existed inside the zeolite pores of CuFe-SSZ-13_SSIE. During hydrothermal aging, the aggregation of these active species in the pores caused the collapse of catalyst structure, ultimately leading to the deactivation of CuFe-SSZ-13_SSIE. In contrast, Fe species was dispersed better on the surface over CuFe-SSZ-13_IE, enhancing the hydrothermal stability of catalysts. Consequently, Fe loading effectively improved the resistance of SO₂ and H₂O over Cu-SSZ-13. For CuFe-SSZ-13, large amounts of active species located inside the zeolite pores are not beneficial for the hydrothermal stability.

Keywords: Active species; CuFe-SSZ-13; NH(3)-SCR performance; NO(x) removal; Preparation methods.

MeSH terms

Air Pollutants / analysis*
Air Pollutants / chemistry
Ammonia / analysis*
Ammonia / chemistry
Catalysis
Ion Exchange
Models, Chemical*
Nitric Oxide / analysis*
Nitric Oxide / chemistry
Oxidation-Reduction
Zeolites / chemistry

Substances

Air Pollutants
Zeolites
Nitric Oxide
Ammonia