The Effect of Copper Loading on the Selective Catalytic Reduction of Nitric Oxide by Ammonia Over Cu-SSZ-13

• Published in: Catalysis letters Vol. 142; no. 3; pp. 295 - 301
• Main Authors: Kwak, Ja Hun, Tran, Diana, Szanyi, Janos, Peden, Charles H. F., Lee, Jong H.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.03.2012; Springer; Springer Nature B.V
• Subjects: AMMONIA; Catalysis; CATALYSTS; Chemistry; Chemistry and Materials Science; COPPER; EFFICIENCY; Environmental Molecular Sciences Laboratory; ENVIRONMENTAL SCIENCES; Exact sciences and technology; General and physical chemistry; Industrial Chemistry/Chemical Engineering; ION EXCHANGE; NITRIC OXIDE; Nitrogen dioxide; Nitrogen oxides; Organometallic Chemistry; OXIDATION; Physical Chemistry; SELECTIVE CATALYTIC REDUCTION; Selectivity; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; VELOCITY; zeolite; ZEOLITES; Zeolites: preparations and properties; Ammonia; Zeolite; Selective catalytic reduction; Copper; Nitric oxide; Nitrogen oxide; Catalytic reaction; Ions; Transition metal; Selectivity; High temperature; Velocity; Molecular sieve; Chemical reduction; Heterogeneous catalysis; Efficiency; Oxidation; Ion exchange; Nitrogen protoxide; Activation energy; Catalyst; Low temperature
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-012-0771-y

The effect of Cu loading on the selective catalytic reduction of NO x by NH 3 was examined over a series of Cu ion-exchanged (20–80%) SSZ-13 zeolite catalysts. High NO reduction efficiencies (80–95%) were obtained over all catalyst samples between 250 and 500 °C, and at the gas hourly space velocity of 200,000 h −1 . Both NO reduction and NH 3 oxidation activities under these conditions were found to increase slightly with increasing Cu loading at low temperatures. However, NO reduction activity was suppressed with increasing Cu loadings at high temperatures (>500 °C) due to excess NH 3 oxidation. The optimum Cu ion exchange level appears to be ~40–60% since higher than 80% NO reduction efficiency was obtained over 50% Cu ion-exchanged SSZ-13 up to 600 °C. The NO oxidation activity of Cu-SSZ-13 was found to be low regardless of Cu loading, although it was somewhat improved with increasing Cu ion exchange level at high temperatures. During the “fast” SCR (i.e., NO/NO 2  = 1), only a slight improvement in NO x reduction activity was obtained for Cu-SSZ-13. Regardless of Cu loading, near 100% selectivity to N 2 was observed; only a very small amount of N 2 O was produced even in the presence of NO 2 . The apparent activation energies for NO oxidation and NO SCR were estimated to be ~58 and ~41 kJ/mol, respectively. Graphical Abstract .