Zinc and phosphorus poisoning tolerance of Cu-SSZ-13 and Ce-Cu-SSZ-13 in the catalytic reduction of nitrogen oxides

SSZ-13 has been commercialized as a catalyst in diesel engines for the selectivity catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3-SCR), but the catalyst is facing the problem of poisoning. Herein, two well-designed catalysts, Cu-SSZ-13 and cerium (Ce) doped Cu-SSZ-13 are synthesized, and their tolerance to zinc (Zn) and phosphorus (P) poisoning alone and together are explored in detail. The research found that Zn and P poisoning alone leads to the destruction of Cu-SSZ-13 structure, resulting in the decline of denitration (de-NOx) performance following the mechanism dominated by Eley-Rideal (E-R). Surprisingly, it is found that zinc phosphate particles are formed at inactive sites on the surface of Cu-SSZ-13 in the presence of Zn and P together, which protects the active sites, enhances the adsorption of nitric oxide. As a result, the excellent de-NOx performance of Cu-SSZ-13 is well maintained following the dual mechanism of E-R and Langmuir-Hinshelwood (L-H). In addition, the introduction of Ce stabilizes the active sites, so as to improve the de-NOx performance and the poisoning tolerance of Cu-SSZ-13. This work deeply analyzes the reasons of Zn and P poisoning and the positive effect of Ce on Cu-SSZ-13, which provides ideas for improving the poisoning tolerance of Cu-SSZ-13 and promotes the further application. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study synthesized two catalysts, Cu-SSZ-13 and cerium-doped Cu-SSZ-13, and explored their tolerance to zinc and phosphorus poisoning. It was found that the presence of zinc and phosphorus together led to the formation of zinc phosphate particles on the surface of Cu-SSZ-13, protecting the active sites and enhancing the de-NOx performance. Additionally, the introduction of cerium stabilized the active sites, further improving the de-NOx performance and poisoning tolerance of Cu-SSZ-13.