Y-Doped Cu-SSZ-39 Zeolite with Only Cu2+-2Z Species: An NH3-SCR Catalyst with Extremely High Hydrothermal Stability

Jinhan Lin; Xueyang Hu; Xuechao Tan; Chunxi Lin; Yan Zhang; Wenpo Shan; Hong He

doi:10.1021/acs.est.5c05828

Y-Doped Cu-SSZ-39 Zeolite with Only Cu²⁺-2Z Species: An NH₃-SCR Catalyst with Extremely High Hydrothermal Stability

Environ Sci Technol. 2025 Jun 30. doi: 10.1021/acs.est.5c05828. Online ahead of print.

Authors

Jinhan Lin^{1

2}, Xueyang Hu^{1

2

3}, Xuechao Tan⁴, Chunxi Lin^{1

3}, Yan Zhang^{1

2}, Wenpo Shan^{1

2}, Hong He^{1

3

5}

Affiliations

¹ Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Science, Xiamen 361021, China.
² Zhejiang Key Laboratory of Pollution Control for Port-Petrochemical Industry, Ningbo Urban Environment Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800, China.
³ University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Center for Ordered Nanoporous Materials Synthesis, Division of Environmental Science and Engineering, POSTECH, Pohang 37673, South Korea.
⁵ State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

PMID: 40583722
DOI: 10.1021/acs.est.5c05828

Abstract

Copper-exchanged SSZ-39 zeolite catalysts have been proven to be more hydrothermally stable than Cu-SSZ-13 catalysts. However, the synthesis of high-silica SSZ-39 zeolites is still a significant challenge. The excess framework Al in Cu-exchanged Al-rich SSZ-39 catalysts leads to not only severe dealumination during hydrothermal aging but also damage to the SCR-active Cu²⁺ ions by the detached Al. In this work, in-depth knowledge of the stabilization of Al by Y is provided. It was found that the energy needed to break the first Al-O bond is significantly enhanced due to the Y³⁺ located in the eight-membered rings. Additionally, Cu²⁺-2Z and Y have a synergistic effect on the stabilization of the framework Al. The introduction of Y into the Cu-SSZ-39 catalyst with hydrothermally stable Cu²⁺-2Z as the only Cu species remarkably enhanced both the low-temperature activity and the hydrothermal stability. The catalyst maintained excellent deNO_x activity even after hydrothermal aging at the extremely high temperature of 940 °C. Both stable Cu species and stable framework Al are essential for the design of hydrothermally stable Cu-exchanged zeolite catalysts.

Keywords: Cu-SSZ-39; Cu2+-2Z; NH3-SCR; Y doping; hydrothermal stability.