Interface Engineering of a Bifunctional Cu-SSZ-13@CZO Core–Shell Catalyst for Boosting Potassium Ion and SO<sub>2</sub> Tolerance
Lingfeng Jia, Jixing Liu, Deqi Huang, Jingchen Zhao, Jianning Zhang, Kaixiang Li, Zhenguo Li, Wenshuai Zhu, Zhen Zhao, Jian Liu
Abstract
The poisoning of sulfur oxides and alkali metals emitted from diesel exhaust to active sites of copper ion-exchanged chabazite (Cu-CHA) catalysts is still present and remains a formidable challenge in practical application. Herein, a bifunctional core–shell structural [email protected] (Cu-SSZ-13@CZO) catalyst was designed and fabricated via a hydrothermally induced self-assembly protocol, and the catalytic activity of Cu-SSZ-13@CZO for selective catalytic reduction (SCR) of nitrogen oxides (NOx) with ammonia was systematically investigated. It unveils that Cu-SSZ-13@CZO features Cu-SSZ-13 as the core and dispersed CZO as the shell and that the CZO shell could not only serve as a sacrificial site protecting the Cu-SSZ-13 active core from SO2 poisoning by the formation of Ce2(SO4)3, which could further act as adsorption sites capturing the K+ through the strong interaction between K+ and cerium sulfate, but also render additional Brønsted acid sites functioning as sacrificial sites to trap K+, thereafter inhibiting the adsorption of K+ directly on active Cu species in the Cu-SSZ-13 core. As a result, the as-constructed Cu-SSZ-13@CZO catalyst, therefore, exhibits perceptibly enhanced coresistance to sulfur and potassium ion poisoning with almost 100% NOx conversion in the temperature window of 275–475 °C as compared to 350–450 °C on pristine Cu-SSZ-13. The finding here may contribute to the fundamental understanding of the coresistance to sulfur oxides and alkali metal poison and thereafter inspire the advancement of a highly efficient NH3-SCR catalyst in the future.