氮氧化物
催化作用
化学
选择性催化还原
三元运算
氮氧化物
无机化学
吸附
钴
烟灰
氨
燃烧
有机化学
计算机科学
程序设计语言
作者
Yonglong Li,Senyou Yang,Honggen Peng,Wenming Liu,Yangyang Mi,Zheng Wang,Changjin Tang,Daishe Wu,Taicheng An
标识
DOI:10.1016/j.jcat.2020.12.036
摘要
Abstract Manganese (Mn)-based mixed oxides are considered the most efficient catalysts for low-temperature ammonia selective catalytic reduction of nitrogen oxides (NOx) (NH3-SCR of NOx). Water resistance and sulfur tolerance, especially the SO2 tolerance of Mn-based catalysts, are the main obstacles preventing their practical application. Therefore, in this study, a series of cobalt (Co)-doped MnFeOx ternary mixed oxides catalysts with a hierarchically ordered structure (Hierc-MnFe1-δCoδOx, δ = 0.2, 0.4 and 0.6) were developed and applied for NH3-SCR of NOx at low temperature. Compared with Hierc-MnFeOx, Hierc-MnFe1-δCoδOx catalyst exhibited enhanced low-temperature activity and a broadened temperature window (NOx conversion above 80% was between 90 and 343 °C over Hierc-MnFe0.6Co0.4Ox), as well as better H2O resistance and SO2 tolerance. The enhanced low-temperature activity was attributed to a larger amount of active oxygen species, a higher proportion of Mn4+, Fe3+ and Co3+ content, and the improvement of surface acidity, which can facilitate the adsorption and activation of NO and NH3. Additionally, the Hierc-MnFe0.6Co0.4Ox catalyst exhibited superior soot tolerance due to its special hierarchically ordered architecture. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that the Co-modified Hierc-MnFe1-δCoδOx ternary oxide catalyst could efficiently protect nitrate species on Hierc-MnFe0.6Co0.4Ox from the poisoning effect of SO2, thereby boosting its SO2 tolerance. This study provides a good candidate for low-temperature deNOx application with enhanced SO2 and soot tolerance.
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