Relationships between Adsorption Amount of Surface Sulfate and NH3-SCR Performance over CeO2

作者：Qiao Xie, Yandi Cai, Lei Zhang, Zhenghua Hu, Tingzhen Li, Xiudie Wang, Qiao Zeng, Xin Wang, Jingfang Sun, Lin Dong · 发表于：The Journal of Physical Chemistry C · 年份：2021 · DOI：10.1021/acs.jpcc.1c06384 · 被引用次数：39 · 研究领域：Catalytic Processes in Materials Science、Industrial Gas Emission Control、Advanced Photocatalysis Techniques

Sulfation is an effective means to improve the reactive performances of pure CeO 2 for selective catalytic reduction of NO by NH 3 (NH 3 -SCR). Herein, CeO 2 is sulfated by SO 2 + O 2 at 150 °C and the amount of sulfate is controlled by sulfation time, and the influence of sulfate amount on the catalytic performances of CeO 2 has been studied. Catalytic tests show that both NO conversion and N 2 selectivity of sulfated CeO 2 are enhanced with increasing sulfate amount. However, catalytic performances nearly keep unchanged when the sulfate amount is over 60% of saturated adsorption. Studies demonstrate that only surface sulfate species existed when CeO 2 is sulfated at 150 °C, and the amount of surface sulfate increases with increasing sulfation time. Then, a corresponding model is proposed to explain the relationships between the adsorption amount of surface sulfate and catalytic performances. More surface sulfate can produce more Brönsted acid sites to improve the activity of sulfated CeO 2 . Moreover, adsorbed sulfate can hinder the formation of surface active oxygen species, resulting in better N 2 selectivity. The NH 3 -SCR reaction can mainly proceed by the Eley–Rideal mechanism over the sulfated CeO 2 .