Effect of ceria doping on catalytic activity and SO2 resistance of MnOx /TiO2 catalysts for selective catalytic reduction of NO with NH3 at low temperature
Effect of ceria doping on catalytic activity and SO2 resistance of MnOx /TiO2 catalysts for selective catalytic reduction of NO with NH3 at low temperature
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DOI：
10.4209/aaqr.2019.10.0546
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发表时间：
2020
影响因子：
4
通讯作者：
Qiulin Wang;Zhou Jianjian;Zhang Jianchao;Hao Zhu;Yuheng Feng;Jing Jin
中科院分区：
文献类型：
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作者：
Qiulin Wang;Zhou Jianjian;Zhang Jianchao;Hao Zhu;Yuheng Feng;Jing Jin
摘要低温NH3-SCR法脱除NO具有工业实用性和低能耗的特点，因此迫切需要一种低温NH3-SCR法脱除NO的工艺。在这项研究中，MnOx-CeO 2/TiO 2（MnCe/Ti）催化剂掺杂不同数量的Ce制备和实验研究其NH3-SCR活性在100°C和400°C之间。添加少量的Ce（Ce/Ti摩尔比为0.05）提高了Mn原子在催化剂表面上的暴露，导致在100°C和200°C之间发生最高的NH3-SCR活性（在175°C下NO的转化率高于98%）。然而，进一步增加Ce含量降低了催化性能。此外，在氧化或还原气氛中NO的NH3-SCR证实，结合到暴露的Mn原子的氧物种更容易释放，并且所产生的空位更容易在低温下被O2补充。此外，引入Ce增强了MnCe/Ti的抗SO2性，主要是通过抑制硫酸铵的积累和Ce掺杂剂的优先硫酸化。
ABSTRACT With its industrial applicability and low energy consumption, a process for implementing the NH3-SCR of NO at low temperatures is urgently needed. In this study, MnOx-CeO2/TiO2 (MnCe/Ti) catalysts doped with different amounts of Ce were prepared and experimentally examined for their NH3-SCR activity between 100°C and 400°C. Adding a small amount of Ce (at the Ce/Ti mole ratio of 0.05) elevated the exposure of Mn atoms on the catalyst surface, resulting in the highest NH3-SCR activity occurring between 100°C and 200°C (with a conversion rate of above 98% for the NO at 175°C). Further increasing the Ce content, however, diminished the catalytic performance. Moreover, the NH3-SCR of NO during oxidization or reduction atmosphere confirmed that oxygen species bound to the exposed Mn atoms were released more easily and the resulting vacancies were more likely to be replenished by O2 at low temperatures. In addition, incorporating Ce enhanced the SO2 resistance of the MnCe/Ti, mainly by inhibiting the accumulation of ammonium sulfates and the preferential sulfation of the Ce dopants.