Pr-modified MnOx catalysts for selective reduction of NO with NH3 at low temperature
Pr-modified MnOx catalysts for selective reduction of NO with NH3 at low temperature
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低温下用 NH3 选择性还原 NO 的 Pr 改性 MnOx 催化剂
DOI：
10.1016/j.jtice.2021.06.008
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发表时间：
2021
影响因子：
5.7
通讯作者：
潘新祥
中科院分区：
文献类型：
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作者：
翟广鹏;韩志涛;吴玺田;杜还;高宇;杨少龙;宋立国;董景明;潘新祥
背景锰氧化物（MnOx）具有优良的低温催化活性，是NH3选择性催化还原NO的理想催化剂。方法采用共沉淀法对MnOx催化剂进行稀土元素Pr改性，考察了Pr改性对MnOx催化剂SCR性能的影响，发现MnPrOx-0. 1催化剂的温度窗口为120 ~ 220 °C，NO转化率接近100%，Pr对MnOx催化剂的改性明显提高了催化剂的抗SO2性能。表征结果表明，Pr改性MnOx催化剂可提高催化剂的比表面积、分散性、还原性、表面Mn 4+和化学吸附氧物种（Oα）的相对百分含量。NH3-TPD和原位DRIFTS结果表明，Pr改性增加了NH3在催化剂表面的吸附，使MnPrOx-0. 1催化剂表面的刘易斯酸中心增多。所有这些因素导致Pr改性的MnOx催化剂具有优异的催化性能。原位DRIFTS结果表明，Pr改性MnOx催化剂上的SCR反应遵循Eley-Rideal（E-R）和Langmuir-Hinshelwood（L-H）机理。
BackgroundManganese oxides (MnOx) are a promising catalyst in selective catalytic reduction of NO with NH3due to their excellent low-temperature catalytic activities. However, MnOxstill suffer from poor N2selectivity and SO2resistance.MethodsIn this work, rare earth element Pr was used to modify MnOxcatalysts via co-precipitation method, and the effects of Pr modification on SCR performance of MnOxcatalysts had been investigated.Significant findingsThe temperature window of MnPrOx-0.1 catalyst with nearly 100% NO conversion efficiency ranged from 120 to 220 °C, and Pr modification on MnOxcatalyst had improved the resistance to SO2obviously. The characterization results indicated that Pr modification on MnOxcatalyst could increase the specific surface area, dispersity, reducibility, relative percentages of surface Mn4+and chemisorbed oxygen species (Oα). NH3-TPD and in-situ DRIFTS results revealed that Pr modification increased the adsorption of NH3on catalyst surface, resulting in more amount of Lewis acid sites on the surface of MnPrOx-0.1 catalyst. All of these factors led to an excellent catalytic performance of Pr-modified MnOxcatalysts. In-situ DRIFTS results implied that SCR reactions over Pr-modified MnOxcatalyst followed both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms.