Effect of mass ratio on micro-mesoporous Cu-SSZ-13/CeWTi composite catalysts for the selective catalytic reduction of NO with ammonia

Wenyi Zhao; Menglin Shen; Yueran Zhu; Dongjie Wang; Xingang Li

doi:10.1039/d1ra03317d

Effect of mass ratio on micro-mesoporous Cu-SSZ-13/CeWTi composite catalysts for the selective catalytic reduction of NO with ammonia

RSC Adv. 2021 Jul 19;11(40):24883-24891. doi: 10.1039/d1ra03317d. eCollection 2021 Jul 13.

Authors

Wenyi Zhao^{1

2}, Menglin Shen^{1

2}, Yueran Zhu², Dongjie Wang², Xingang Li¹

Affiliations

¹ Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin Key Laboratory of Applied Catalysis Science & Technology, School of Chemical Engineering & Technology, Tianjin University Tianjin 300350 China xingang_li@tju.edu.cn.
² National Key Laboratory for Research and Comprehensive Utilization of Rare Earth Resources in Baiyun Obo, Baotou Research Institute of Rare Earths Baotou 014030 China.

Abstract

A series of micro-mesoporous SSZ-13/CexWyTiz composites with different zeolite/oxide ratios were synthesized using a one-step crystallization method. The effects of the mass ratio on the crystal form, specific surface area, pore structure, surface element properties, redox properties, surface acidity and deNO _x performance of the Cu-SSZ-13/CeWTi composite catalysts were investigated using X-ray diffractometry (XRD), Brunauer-Emmett-Teller analysis (BET), X-ray photoelectron spectroscopy (XPS), H₂ temperature programmed reduction (H₂-TPR) and NH₃ temperature programmed desorption (NH₃-TPD). The results reveal that the Cu-SSZ-13/CeWTi composite catalysts formed a micro-mesoporous structure. The increase in the mass ratio leads to the increased microporous ratio of the composite catalysts, the improved crystal structure of SSZ-13 and a higher specific surface area and pore volume, which is conducive to enhancing the low-temperature deNO _x activity, but its high-temperature performance (450 °C and above) decreases. The introduction of micropores into mesoporous materials can result in the production of more Ce⁴⁺, surface chemisorption oxygen species O_α and acid sites. The Cu-SSZ-13/CeWTi composite catalyst with a mass ratio of 1 : 4 demonstrated the best micro-mesoporous ratio, low-temperature selective catalytic reduction (SCR) performance and hydrothermal stability.