Deterioration Analysis of Real-world SCR Catalysts in Diesel Vehicles

Article Deterioration Analysis of Real-world SCR Catalysts in Diesel Vehicles Tongliang Zhang 1,2,3, Yu Sun 3, Xusheng Xiang 4, Wenqing Ding 2,3, Zhen Chen 4, Caiyue Dong 4, Yating Li 3, Yulong Shan 3,*, Yunbo Yu 2,3 and Hong He 1,2,3 1 School of Rare Earths, University of Science and Technology of China, Hefei 230026, China 2 Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China 3 State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 4 Dongfeng Commercial Vehicle Co., Ltd., Shiyan 100049, China * Correspondence: [email protected] Received: 12 August 2024; Revised: 22 October 2024; Accepted: 24 October 2024; Published: 28 November 2024 Abstract: To investigate the real-world poisoning of Cu-SSZ-13 NH3-SCR (Selective Catalytic Reduction with NH3) catalysts in diesel vehicles, three used catalysts from vehicles that have traveled different distances were analyzed. The deterioration observed in these catalysts significantly differs from laboratory simulations due to the combined effect of multiple poisoning factors. The degree of catalyst deterioration is positively correlated not only with driving distance but also with the specific types of poisoning encountered. In real-world conditions, hydrothermal aging is not the primary poisoning factor. Instead, the main cause of Cu-SSZ-13 deactivation is the poisoning by chemical elements such as sulfur and iron. Sulfur poisoning reduces catalytic activity, and the regeneration of the catalyst depends on the species formed. This study reveals that the accumulation of chemical poisons is the primary reason for the deterioration of Cu-SSZ-13 catalysts in real-world conditions. Therefore, reducing toxic components in diesel engine exhaust is essential for maintaining catalyst performance.