Porous washcoat structure in CeO<sub>2</sub> modified Cu‐SSZ‐13 monolith catalyst for NH<sub>3</sub>‐SCR with improved catalytic performance
Wuyuan Liu, Zhaoying Wang, Ming Sun, Jiajian Gao, Lifeng Wang, Zihan Gao, Yingying Xu, Xiangyun Zhao, Cheng Zhang, Lin Yu
Abstract
Abstract A series of CeO 2 modified Cu‐SSZ‐13 monolith catalysts were prepared by embedding CeO 2 into the washcoat of Cu‐SSZ‐13 monolith catalyst through solvent combustion method. These CexCu‐SSZ‐13 catalysts were studied in the selective catalytic reduction (SCR) of NO with NH 3 , among which the Ce2Cu‐SSZ‐13 catalyst exhibited the best low‐temperature activity, hydrothermal stability, and sulfur resistance. The physicochemical properties of the catalysts were characterized using multiple methods. Results showed that the acidity, redox capacity, and ammonia adsorption capacity significantly enhanced after CeO 2 modification, thus leading to the high performance of Ce2Cu‐SSZ‐13 catalyst. Furthermore, the introduction of CeO 2 induced the fast SCR reaction by promoting the oxidation of NO to NO 2 . Analog calculation suggested that the porous structure generated via solvent combustion in the washcoat effectively increased the diffusion rate of reaction. In situ diffuse reflectance infrared Fourier transform spectroscopy ( in situ DRIFT) analysis showed that Brønsted acid sites were the main active center and the reaction followed Eley–Rideal mechanism.