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铜站点运动促进了热催化NO 在热带石限制下减少

Dongdong Chen¹, Abhishek Khetan², Huarong Lei^1,3

¹National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China.

Environmental science & technology

|October 16, 2023

概括

强化焦石中的铜 (Cu) 位点运动增强了氨介导的氧化物 (NO) 清除的选择性催化还原 (NH-SCR). 这提高了低温性能,这对于车辆冷启动排放至关重要.

科学领域:

环境催化剂环境催化剂
材料科学材料科学材料科学
化学工程是化学工程的重要组成部分.

背景情况:

使用与铜交换的酸盐 (Cu-CHA) 酸盐的氨介选择性催化还原 (NH₃-SCR) 对于从重型车辆中减少氧化 (NO) 是至关重要的.
当前的NH₃-SCR催化剂在200°C以下表现不佳,在冷启动条件下限制了它们的有效性,并且未能满足严格的排放标准.

研究的目的:

为了研究热石限制铜 (Cu) 位点的动态运动及其对低温NH₃-SCR性能的影响.
阐明单价铜 (Cu(I)) 在Cu流动性中的作用及其在分子水平上对催化活性的贡献.

主要方法:

利用复杂的基于阻抗的现场光谱 (IS) 来研究岩格子内的Cu位点的环境和温度依赖的动态运动.
结合in situ IS与红外光谱学,揭示了控制Cu流动性的分子层次机制,特别是Cu的作用.
采用扩展密度功能紧结分子动力学模拟来补充实验发现.

主要成果:

证明了加强受热石限制的Cu位点的动态运动显著促进了低温NO减少 (低于200°C).
确定了单价铜 (Cu(I)) 在增强热岩结构内的整体Cu流动性方面发挥的关键作用.
通过简单的后合成处理,通过各种Cu-zeolites (例如,Cu-CHA,Cu-ZSM-5,Cu-Beta) 的NO减少效率得到了大幅提高.

结论:

位的动态运动是有效的低温NH₃-SCR的关键因素.
有针对性的合成后处理可以提高Cu的流动性,从而提高车辆排放控制的催化性能.
了解Cu的移动机制为设计下一代催化剂提供了一条途径,以满足严格的环境法规.

关键词:

的移动性的移动性在GFN-xTB模拟中进行模拟.在XASAS中,XAS就是XAS.在现场的IS-DRIFTS.分子动力学分子动力学

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