Promotional mechanisms of activity and SO2 tolerance of Co- or Ni-doped MnOx-CeO2 catalysts for SCR of NOx with NH3 at low temperature
Promotional mechanisms of activity and SO2 tolerance of Co- or Ni-doped MnOx-CeO2 catalysts for SCR of NOx with NH3 at low temperature
复制标题
Co或Ni掺杂MnOx-CeO2催化剂低温NH3 SCR催化活性和SO2耐受性的促进机制
DOI：
10.1016/j.cej.2017.02.042
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发表时间：
2017-06-01
影响因子：
15.1
通讯作者：
Li, Chenlu
中科院分区：
文献类型：
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作者：
Gao, Fengyu;Tang, Xiaolong;Li, Chenlu
采用共沉淀法制备了金属掺杂的MnOx-CeO 2催化剂（M：Mn：Ce = 1：4：5（M = Cu，Co，Cr，Ni，Fe，Sn，Mg）），用于低温NH3选择性催化还原NOx（NOx-NH3-SCR）。结果表明，Co/Ni掺杂催化剂具有较高的SCR性能和较好的抗SO2性能。Co/Ni掺杂的催化剂具有更高的比表面积和更小的孔径。XPS分析表明，Co/Ni掺杂的催化剂具有更多的化学吸附氧、更多的活性位（Mn 3+和Mn 4+）和更高的Ce 4 +/Ce 3+比值，有利于提高催化剂的SCR活性，并伴随着快速SCR反应，从而提高催化剂的NO氧化活性。原位DRIFTS结果表明，在不受SO2影响的情况下，Co/Ni掺杂催化剂上的NOx吸附物种倾向于双齿硝酸盐，并进一步转化为单齿硝酸盐，产生新的Bronsted酸中心吸附NH 4 +.而MnOx-CeO 2催化剂上的亚硝酸盐更有利于单齿亚硝酸盐物种的形成，SO2对亚硝酸盐物种的形成有明显的抑制作用。热重分析（TGA）表明，Co/Ni掺杂催化剂上硫酸铵和金属硫酸盐物种的形成显着抑制。提出了Co/Ni掺杂催化剂与MnOx-CeO 2催化剂的SCR反应途径和抗SO2机理。(c)2017爱思唯尔B. V.保留所有权利。
Metals doped MnOx-CeO2 catalysts with a molar ratio of M:Mn:Ce = 1:4:5 (M = Cu, Co, Cr, Ni, Fe, Sn, Mg) were prepared by a co-precipitation method for low-temperature selective catalytic reduction of NOx with NH3 (NOx-NH3-SCR). The results showed Co/Ni doped catalysts had high SCR performance and good tolerance to SO2. Solid solutions with higher surface area and smaller pore size were obtained over Co/Ni doped catalysts. XPS analysis presented Co/Ni doped catalysts had more chemisorbed oxygen, more active sites (Mn3+ and Mn4+) and higher ratio of Ce4+/Ce3+, which were favorable for improving the SCR activity accompanied by the fast-SCR due to a high activity for NO oxidation to NO2. The in-situ DRIFTS revealed NOx-absorbed species over Co/Ni doped catalysts tended to bidentate nitrate without influences by SO2, which further transformed to monodentate nitrate producing new Bronsted acid sites for adsorbing NH4+. While that over MnOx-CeO2 catalyst was more in favor of monodentate nitrite species, significantly inhibiting by SO2. Thermogravimetric analysis (TGA) presented the formations of ammonium sulfate and metal sulfate species over Co/Ni doped catalysts were markedly inhibited. The possible SCR reaction pathways and mechanisms of SO2 tolerance were proposed over Co/Ni doped catalysts contrasted to MnOx-CeO2 catalyst. (c) 2017 Elsevier B.V. All rights reserved.