Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Institute for Integrated Catalysis
Tiangong University, Tianjin (China)
Pohang University of Science and Technology (POSTECH), Pohang (Korea, Republic of)
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Institute for Integrated Catalysis; Polish Academy of Sciences (PAS), Krakow (Poland)
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Institute for Integrated Catalysis; Washington State University, Pullman, WA (United States)
Low-temperature standard NH3-SCR over copper-exchanged zeolite catalysts occurs on NH3-solvated Cu-ion active sites in a quasi-homogeneous manner. As key kinetically relevant reaction steps, the reaction intermediate CuII(NH3)4 ion hydrolyzes to CuII(OH)(NH3)3 ion to gain redox activity. The CuII(OH)(NH3)3 ion also transfers between neighboring zeolite cages to form highly reactive reaction intermediates. Via operando electron paramagnetic resonance spectroscopy and SCR kinetic measurements and density functional theory calculations, we demonstrate here that such kinetically relevant steps become energetically more difficult with lower support Brønsted acid strength and density. Consequently, Cu/LTA displays lower Cu atomic efficiency than Cu/CHA and Cu/AEI, which can also be rationalized by considering differences in their support topology. By carrying out hydrothermal aging to eliminate support Brønsted acid sites, both CuII(NH3)4 ion hydrolysis and CuII(OH)(NH3)3 ion migration are hindered, leading to a marked decrease in Cu atomic efficiency for all catalysts.
Wu, Yiqing, et al. "Interplay between copper redox and transfer and support acidity and topology in low temperature NH<sub>3</sub>-SCR." Nature Communications, vol. 14, no. 1, May. 2023. https://doi.org/10.1038/s41467-023-38309-8
Wu, Yiqing, Zhao, Wenru, Ahn, Sang Hyun, Wang, Yilin, Walter, Eric D., Chen, Ying, Derewinski, Miroslaw A., Washton, Nancy M., Rappé, Kenneth G., Wang, Yong, Mei, Donghai, Hong, Suk Bong, & Gao, Feng (2023). Interplay between copper redox and transfer and support acidity and topology in low temperature NH<sub>3</sub>-SCR. Nature Communications, 14(1). https://doi.org/10.1038/s41467-023-38309-8
Wu, Yiqing, Zhao, Wenru, Ahn, Sang Hyun, et al., "Interplay between copper redox and transfer and support acidity and topology in low temperature NH<sub>3</sub>-SCR," Nature Communications 14, no. 1 (2023), https://doi.org/10.1038/s41467-023-38309-8
@article{osti_1974565,
author = {Wu, Yiqing and Zhao, Wenru and Ahn, Sang Hyun and Wang, Yilin and Walter, Eric D. and Chen, Ying and Derewinski, Miroslaw A. and Washton, Nancy M. and Rappé, Kenneth G. and Wang, Yong and others},
title = {Interplay between copper redox and transfer and support acidity and topology in low temperature NH<sub>3</sub>-SCR},
annote = {Low-temperature standard NH3-SCR over copper-exchanged zeolite catalysts occurs on NH3-solvated Cu-ion active sites in a quasi-homogeneous manner. As key kinetically relevant reaction steps, the reaction intermediate CuII(NH3)4 ion hydrolyzes to CuII(OH)(NH3)3 ion to gain redox activity. The CuII(OH)(NH3)3 ion also transfers between neighboring zeolite cages to form highly reactive reaction intermediates. Via operando electron paramagnetic resonance spectroscopy and SCR kinetic measurements and density functional theory calculations, we demonstrate here that such kinetically relevant steps become energetically more difficult with lower support Brønsted acid strength and density. Consequently, Cu/LTA displays lower Cu atomic efficiency than Cu/CHA and Cu/AEI, which can also be rationalized by considering differences in their support topology. By carrying out hydrothermal aging to eliminate support Brønsted acid sites, both CuII(NH3)4 ion hydrolysis and CuII(OH)(NH3)3 ion migration are hindered, leading to a marked decrease in Cu atomic efficiency for all catalysts.},
doi = {10.1038/s41467-023-38309-8},
url = {https://www.osti.gov/biblio/1974565},
journal = {Nature Communications},
issn = {ISSN 2041-1723},
number = {1},
volume = {14},
place = {United States},
publisher = {Nature Publishing Group},
year = {2023},
month = {05}}
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
National Research Foundation of Korea; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO); USDOE Office of Science (SC), Biological and Environmental Research (BER)