One-pot hydrothermal synthesis of dual metal incorporated CuCe-SAPO-34 zeolite for enhancing ammonia selective catalytic reduction
One-pot hydrothermal synthesis of dual metal incorporated CuCe-SAPO-34 zeolite for enhancing ammonia selective catalytic reduction
复制标题
一锅水热合成双金属 CuCe-SAPO-34 沸石增强氨选择性催化还原
DOI：
10.1016/j.jhazmat.2020.124177
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发表时间：
2021
影响因子：
13.6
通讯作者：
Zhang Shihong
中科院分区：
文献类型：
--
作者：
Zhou Xiaoming;Chen Zhuoyuan;Guo Zhiyong;Yang Haiping;Shao Jingai;Zhang Xiong;Zhang Shihong
以二乙胺为有机结构导向剂，采用一锅法水热合成了一系列双金属掺杂的CuCex-SAPO-34（x = 0 ~ 0. 04）催化剂，用于NH3选择性催化还原NOx.详细阐述了催化性能，并使用各种仪器分析了理化性质。所有催化剂均具有典型的SAPO-34晶体结构和高比表面积。随着双金属的掺入，表面酸性和孤立的Cu 2+，这可能是NH3-SCR的活性中心的量，显着提高。但过量的Ce由于占据阳离子中心，抑制了孤立Cu ~（2+）的形成。因此，0.05CuCe0.02-SAPO-34在168°C-500°C范围内表现出较高的NO转化率（≥80%）。此外，在原位DRIFTS实验中研究了不同催化剂上的NH3-SCR反应机理。对于0. 05 Cu-SAPO-34，在整个反应温度范围内，吸附的NH3物种与气态NO的反应遵循E-R机理。同时，在低温区，吸附态NO2与吸附态NH3按L-H机理反应。相比之下，在0.05CuCe 0.02-SAPO-34上的NH3-SCR反应在整个温度范围内主要遵循E-R机理。由于高温下亚氮物种的吸附能力丧失，L-H机理被切断。导致NO转化率降低。
A series of dual metal incorporated CuCex-SAPO-34(x = 0–0.04) samples were synthesized using one-pot hydrothermal method with diethylamine as organic structure-directing agent for selective catalytic reduction of NOxby NH3. The catalytic properties were elucidated in detail with physicochemical properties being analyzed using various instruments. All the catalysts exhibited typical SAPO-34 crystal structures with high specific surface areas. With the dual-metal incorporation, the surface acidity and amount of isolated Cu2+, which may be active sites for NH3-SCR, were significantly enhanced. However, excessive Ce restrained the formation of isolated Cu2+due to its occupation of cationic sites. Therefore, the 0.05CuCe0.02-SAPO-34 exhibited high NO conversion (≥80%) at 168°C-500°C. Furthermore, the NH3-SCR mechanism over different catalysts was investigatedin-situDRIFTS experiments. For the 0.05Cu-SAPO-34, the adsorbed NH3species react with gaseous NO and following the E-R mechanism throughout the reaction temperature range. Meanwhile, adsorbed NO2was detected and reacted with the adsorbed NH3species according to the L-H mechanism in low-temperature region. In contrast, the NH3-SCR reaction over the 0.05CuCe0.02-SAPO-34 primarily followed the E-R mechanism throughout the temperature range. The L-H mechanism was cut off due to the loss of the adsorption ability of nitrous species at high temperatures., resulting in NO conversion decreasing.