Zhou Xiaoming, Chen Zhuoyuan, Guo Zhiyong, Yang Haiping, Shao Jingai, Zhang Xiong, Zhang Shihong
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074 Wuhan, China.
School of Energy and Power Engineering, Huazhong University of Science and Technology, 430074 Wuhan, China.
J Hazard Mater. 2021 Mar 5;405:124177. doi: 10.1016/j.jhazmat.2020.124177. Epub 2020 Oct 8.
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 NO by NH. 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 Cu, which may be active sites for NH-SCR, were significantly enhanced. However, excessive Ce restrained the formation of isolated Cu 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 NH-SCR mechanism over different catalysts was investigated in-situ DRIFTS experiments. For the 0.05Cu-SAPO-34, the adsorbed NH species react with gaseous NO and following the E-R mechanism throughout the reaction temperature range. Meanwhile, adsorbed NO was detected and reacted with the adsorbed NH species according to the L-H mechanism in low-temperature region. In contrast, the NH-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.
采用一锅水热法，以二乙胺为有机结构导向剂，合成了一系列双金属掺杂的CuCex-SAPO-34（x = 0 - 0.04）样品，用于NH3选择性催化还原NO。通过各种仪器分析其物理化学性质，详细阐明了催化性能。所有催化剂均呈现出具有高比表面积的典型SAPO-34晶体结构。双金属掺杂后，可能作为NH3-SCR活性位点的表面酸度和孤立Cu的数量显著提高。然而，过量的Ce由于占据阳离子位点而抑制了孤立Cu的形成。因此，0.05CuCe0.02-SAPO-34在168°C - 500°C时表现出高NO转化率（≥80%）。此外，通过原位漫反射红外傅里叶变换光谱（DRIFTS）实验研究了不同催化剂上的NH3-SCR反应机理。对于0.05Cu-SAPO-34，吸附的NH3物种与气态NO反应，在整个反应温度范围内遵循E-R机理。同时，在低温区域检测到吸附的NO，并根据L-H机理与吸附的NH3物种反应。相比之下，0.05CuCe0.02-SAPO-34上的NH3-SCR反应在整个温度范围内主要遵循E-R机理。由于高温下亚硝酸盐物种吸附能力的丧失，L-H机理被切断，导致NO转化率下降。
