Cu-exchanged RTH-type zeolites for NH3-selective catalytic reduction of NOx: Cu distribution and hydrothermal stability
Cu-exchanged RTH-type zeolites for NH3-selective catalytic reduction of NOx: Cu distribution and hydrothermal stability
复制标题
用于 NH3 选择性催化还原 NOx 的 Cu 交换 RTH 型沸石：Cu 分布和水热稳定性
DOI：
10.1039/c8cy01933a
复制
发表时间：
2019-01-07
影响因子：
5
通讯作者：
He, Hong
中科院分区：
文献类型：
--
作者：
Shan, Yulong;Shi, Xiaoyan;He, Hong
The Cu-exchanged RTH-type zeolites (Cu-RTH) were applied in ammonia-selective catalytic reduction (NH3-SCR) of NOx. The effects of Cu loading and distribution on the NOx reduction efficiency were investigated. The hydrothermal stabilities of a series of Cu-RTH catalysts were also presented. Excellent NOx conversion activity was observed for Cu-RTH catalysts with high Cu loadings (2.5-4.4 wt%) in the temperature range from 150 degrees C to 550 degrees C. Two possible sites ( and species) for Cu2+ species were proposed based on the analysis of H-2-TPR and DRIFTS results. The species next to the 8-membered rings showed significantly higher TOF (turnover frequency) of NO conversion than the species present next to the rth cage. The Cu-RTH catalysts showed lower activation energies (30-40 kJ mol(-1)) compared with that of the Cu-SSZ-13 catalyst (approximate to 54 kJ mol(-1)) due to the different zeolite framework structures. After undergoing hydrothermal aging, although the zeolite framework structure stayed stable, the active Cu2+ species migrated to inactive sites, which resulted in the loss of NOx conversion for the NH3-SCR reaction. The saturated Cu2+-exchanged Cu-4.4-RTH catalyst showed the best hydrothermal stability due to the limited Cu2+ mobility, which stabilized the active Cu2+ species.
