Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands.
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
Nat Commun. 2017 Nov 21;8(1):1666. doi: 10.1038/s41467-017-01765-0.
Copper-exchanged zeolite chabazite (Cu-SSZ-13) was recently commercialized for the selective catalytic reduction of NO with ammonia in vehicle emissions as it exhibits superior reaction performance and stability compared to all other catalysts, notably Cu-ZSM-5. Herein, the 3D distributions of Cu as well as framework elements (Al, O, Si) in both fresh and aged Cu-SSZ-13 and Cu-ZSM-5 are determined with nanometer resolution using atom probe tomography (APT), and correlated with catalytic activity and other characterizations. Both fresh catalysts contain a heterogeneous Cu distribution, which is only identified due to the single atom sensitivity of APT. After the industry standard 135,000 mile simulation, Cu-SSZ-13 shows Cu and Al clustering, whereas Cu-ZSM-5 is characterized by severe Cu and Al aggregation into a copper aluminate phase (CuAlO spinel). The application of APT as a sensitive and local characterization method provides identification of nanometer scale heterogeneities that lead to catalytic activity and material deactivation.
铜交换沸石 CHABAZITE（Cu-SSZ-13）最近在车辆排放物的氨选择性催化还原中实现了商业化，因为与所有其他催化剂相比，它表现出优越的反应性能和稳定性，尤其是 Cu-ZSM-5。在此，使用原子探针层析技术（APT）以纳米分辨率确定了新鲜和老化的 Cu-SSZ-13 和 Cu-ZSM-5 中 Cu 以及骨架元素（Al、O、Si）的 3D 分布，并与催化活性和其他特性相关联。两种新鲜的催化剂都含有不均匀的 Cu 分布，这仅仅是由于 APT 的单原子灵敏度才得以识别。在经过行业标准的 135000 英里模拟后，Cu-SSZ-13 显示 Cu 和 Al 聚集，而 Cu-ZSM-5 的特点是 Cu 和 Al 严重聚集形成铜铝酸盐相（CuAlO 尖晶石）。APT 作为一种灵敏和局部的表征方法的应用提供了对导致催化活性和材料失活的纳米级异质性的识别。
