Isolation of the Copper Redox Steps in the Standard Selective Catalytic Reduction on Cu-SSZ-13

Journal Article · Fri Sep 12 00:00:00 EDT 2014 · Angewandte Chemie (International Edition)

DOI:https://doi.org/10.1002/anie.201407030· OSTI ID:1392942

Paolucci, Christopher; Verma, Anuj A.; Bates, Shane A.; Kispersky, Vincent F.; Miller, Jeffrey T.; Gounder, Rajamani; Delgass, W. Nicholas; Ribeiro, Fabio H.; Schneider, William F.

Operando X-ray absorption experiments and density functional theory (DFT) calculations are reported that elucidate the role of copper redox chemistry in the selective catalytic reduction (SCR) of NO over Cu-exchanged SSZ-13. Catalysts prepared to contain only isolated, exchanged CuII ions evidence both CuII and CuI ions under standard SCR conditions at 473 K. Reactant cutoff experiments show that NO and NH3 together are necessary for CuII reduction to CuI. DFT calculations show that NO-assisted NH3 dissociation is both energetically favorable and accounts for the observed CuII reduction. The calculations predict in situ generation of Brønsted sites proximal to CuI upon reduction, which we quantify in separate titration experiments. Both NO and O2 are necessary for oxidation of CuI to CuII, which DFT suggests to occur by a NO2 intermediate. Reaction of Cu-bound NO2 with proximal NH4 + completes the catalytic cycle. N2 is produced in both reduction and oxidation half-cycles.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Office of Vehicle Technology; National Science Foundation (NSF); USDOE Office of Science - Office of Basic Energy Sciences - Chemical Sciences, Geosciences, and Biosciences Division
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1392942
• Journal Information: Angewandte Chemie (International Edition), Vol. 53, Issue 44; ISSN 1433-7851
• Publisher: Wiley
• Country of Publication: United States
• Language: English