Nanoscale tomography reveals the deactivation of automotive copper-exchanged zeolite catalysts. Issue 1 (December 2017)

• Record Type: Journal Article
• Authors: Schmidt, Joel; Oord, Ramon; Guo, Wei; Poplawsky, Jonathan; Weckhuysen, Bert
• Is Part Of: Nature communications. Volume 8:Issue 1(2017)
• Page Start: 1
• Page End: 8
• Publication Date: 2017-12
• Subjects: Biology -- Periodicals; Physical sciences -- Periodicals; 505
• DOI: 10.1038/s41467-017-01765-0
• Languages: English
• ISSNs: 2041-1723

Abstract

Abstract Copper-exchanged zeolite chabazite (Cu-SSZ-13) was recently commercialized for the selective catalytic reduction of NOX 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 (CuAl2 O4 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. Cu-exchanged zeolite chabazite has superior stability over other catalysts in automotive NOx reduction. Here, the authors use atom probe tomography to create 3D nanoscale reconstructions of two Cu-containing zeolite catalysts, providing a complete picture of their deactivation mechanisms during aging.