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Title: Selective Catalytic Reduction over Cu/SSZ-13: Linking Homo- and Heterogeneous Catalysis

Abstract

Active centers in Cu/SSZ-13 selective catalytic reduction (SCR) catalysts have been recently identified as isolated Cu2+ and [CuII(OH)]+ ions. A redox reaction mechanism has also been established, where Cu-ions cycle between CuI and CuII oxidation states during SCR reaction. While the mechanism for the reduction half-cycle (CuII CuI) is reasonably well understood, that for the oxidation half-cycle (CuI CuII) remains an unsettled debate. Herein we report detailed reaction kinetics on low-temperature standard NH3-SCR, supplemented by DFT calculations, as strong evidence that the low-temperature oxidation half-cycle occurs with the participation of two isolated CuI ions, via formation of a transient [CuI(NH3)2]+-O2-[CuI(NH3)2]+ intermediate. The feasibility of this reaction mechanism is confirmed from DFT calculations, and the simulated energy barrier and rate constants are consistent with experimental findings. Significantly, the low-temperature standard SCR mechanism proposed here provides full consistency with low-temperature SCR kinetics. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest Nationalmore » Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.« less

Authors:
ORCiD logo; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1369506
Report Number(s):
PNNL-SA-123327
Journal ID: ISSN 0002-7863; 47953; VT0401000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Chemical Society; Journal Volume: 139; Journal Issue: 13
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; selective catalytic reduction; Cu/SSZ-13; reaction mechanism; reaction kinetics; Environmental Molecular Sciences Laboratory

Citation Formats

Gao, Feng, Mei, Donghai, Wang, Yilin, Szanyi, János, and Peden, Charles H. F. Selective Catalytic Reduction over Cu/SSZ-13: Linking Homo- and Heterogeneous Catalysis. United States: N. p., 2017. Web. doi:10.1021/jacs.7b01128.
Gao, Feng, Mei, Donghai, Wang, Yilin, Szanyi, János, & Peden, Charles H. F. Selective Catalytic Reduction over Cu/SSZ-13: Linking Homo- and Heterogeneous Catalysis. United States. doi:10.1021/jacs.7b01128.
Gao, Feng, Mei, Donghai, Wang, Yilin, Szanyi, János, and Peden, Charles H. F. Tue . "Selective Catalytic Reduction over Cu/SSZ-13: Linking Homo- and Heterogeneous Catalysis". United States. doi:10.1021/jacs.7b01128.
@article{osti_1369506,
title = {Selective Catalytic Reduction over Cu/SSZ-13: Linking Homo- and Heterogeneous Catalysis},
author = {Gao, Feng and Mei, Donghai and Wang, Yilin and Szanyi, János and Peden, Charles H. F.},
abstractNote = {Active centers in Cu/SSZ-13 selective catalytic reduction (SCR) catalysts have been recently identified as isolated Cu2+ and [CuII(OH)]+ ions. A redox reaction mechanism has also been established, where Cu-ions cycle between CuI and CuII oxidation states during SCR reaction. While the mechanism for the reduction half-cycle (CuII CuI) is reasonably well understood, that for the oxidation half-cycle (CuI CuII) remains an unsettled debate. Herein we report detailed reaction kinetics on low-temperature standard NH3-SCR, supplemented by DFT calculations, as strong evidence that the low-temperature oxidation half-cycle occurs with the participation of two isolated CuI ions, via formation of a transient [CuI(NH3)2]+-O2-[CuI(NH3)2]+ intermediate. The feasibility of this reaction mechanism is confirmed from DFT calculations, and the simulated energy barrier and rate constants are consistent with experimental findings. Significantly, the low-temperature standard SCR mechanism proposed here provides full consistency with low-temperature SCR kinetics. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.},
doi = {10.1021/jacs.7b01128},
journal = {Journal of the American Chemical Society},
number = 13,
volume = 139,
place = {United States},
year = {Tue Mar 21 00:00:00 EDT 2017},
month = {Tue Mar 21 00:00:00 EDT 2017}
}