Novel framework-confined Cu@ 13X catalyst with excellent resistance to toxic SO as an eco-friendly substitute for hazardous V-based NH-SCR catalyst.

VO-WO/TiO (VWTi) catalyst has long been utilized in fixed source flue gases to purify harmful NO gas. However, VWTi is classified as a hazardous material because of its harm to human health and environment. To address this issue, a low-cost green Cu-based zeolite catalyst (Cu@13X) with a wide temperature range was synthesized using an in-situ hydrothermal method. This method is intended to control the adsorption capacity of toxic SO by regulating the location of Cu species. UV-Vis DRS and EXAFS analyses revealed that a significant amount of Cu was encapsulated within the 12-membered ring pores of the 13X molecular sieve. SO-TPD and DFT calculations further indicated that Cu@ 13X exhibits reduced SO chemical adsorption capacity. Consequently, this green catalyst demonstrated superior catalytic performance, maintaining superior NO conversion for over 70 h in the mixture gas containing 250 ppm SO; while the Cu/13X catalyst lacked NH-SCR catalytic activity under the same conditions. Moreover, Cu@ 13X catalyst also has excellent NH-SCR catalytic performance in low temperature flue gas below 250 °C, which is significantly better than the hazardous VWTi catalyst. Characterization techniques such as NH-TPD, H-TPR, and XPS confirmed that the Cu@ 13X catalyst possesses excellent acidity, robust redox capabilities, and abundant surface defects. In-situ DRIFT spectra further illustrated that the NH-SCR reaction on the catalyst surface adheres to the Eley-Rideal mechanism both before and after the introduction of toxic SO. This study offers a fresh perspective on the development of framework-confined NH-SCR catalysts and elucidates the mechanism behind the sulfur resistance of these catalysts. And the green Cu@ 13X catalyst is anticipated to serve as an effective alternative to the hazardous VWTi catalyst.