Journal of the Taiwan Institute of Chemical Engineers ( IF 5.5 ) Pub Date : 2021-11-18 , DOI: 10.1016/j.jtice.2021.11.011 Xiaodi Li 1 , Zhitao Han 2, 3 , Xinxin Wang 2 , Shaolong Yang 4 , Gang Liu 2 , Yu Gao 2 , Chenglong Li 2
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Background
Due to excellent oxygen storage capacity and redox ability, Ce-based catalysts are usually considered as one of the promising candidates of traditional V-based catalysts for NH3-SCR of NO. However, surface acidity of Ce-based catalysts is often insufficient which restrains their SCR performance to some extent.
Methods
Herein, ZrO2-supported CeO2 catalysts were prepared by precipitation and wet impregnation methods. Aiming to promote catalyst surface acidity, a novel method was proposed to pre-treat ZrO2 support with various acids (HCl, HNO3, H3PO4 and H2SO4) via impregnation process. and the effects of acid treatment on SCR performance of CeO2/ZrO2 catalysts had been investigated.
Significant findings
It was worthy to note that H2SO4-treated CeO2/ZrO2 catalyst exhibited a superior NO removal efficiency which was higher than 94% in a wide temperature range of 248–500 °C. NH3-TPD results revealed that the surface acidities acidity of CeO2/ZrO2 catalysts had been obviously enhanced after acid treatment with HNO3, H3PO4 and H2SO4, except for HCl. According to in-situ DRIFRS results, one could infer that SCR reactions occurred over CeO2/ZrO2 catalyst without acid treatment might proceed only in E-R mechanism. But for acid-treated CeO2/ZrO2 catalysts, both E-R and L-H mechanisms were might be followed in SCR reaction process.
中文翻译：
ZrO2 负载 CeO2 催化剂对 NO NH3-SCR 的酸处理：对表面酸度和反应机理的影响
背景
由于优异的储氧能力和氧化还原能力，Ce基催化剂通常被认为是传统V基催化剂用于NO的NH 3 -SCR的有希望的候选者之一。然而，铈基催化剂的表面酸性往往不足，这在一定程度上限制了它们的 SCR 性能。
方法
在此，ZrO 2负载的CeO 2催化剂通过沉淀法和湿法浸渍法制备。为提高催化剂表面酸性，提出了一种用各种酸（HCl、HNO 3、H 3 PO 4和H 2 SO 4）通过浸渍法预处理ZrO 2载体的新方法。并研究了酸处理对CeO 2 /ZrO 2催化剂的SCR性能的影响。
重要发现
值得注意的是，H 2 SO 4处理的CeO 2 /ZrO 2催化剂在248-500℃的宽温度范围内表现出优异的NO去除效率，高于94％。NH 3 -TPD结果表明，除HCl外，经HNO 3、H 3 PO 4和H 2 SO 4酸处理后，CeO 2 /ZrO 2催化剂的表面酸度明显提高。根据原位 DRIFRS 结果，可以推断 SCR 反应发生在 CeO 2 /ZrO 2上未经酸处理的催化剂可能仅在 ER 机制中进行。但对于酸处理的CeO 2 /ZrO 2催化剂，在SCR反应过程中可能同时遵循ER和LH机理。
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