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Activation of Oxygen and NO in NH3-SCR over Cu-CHA Catalysts Evaluated by Density Functional Theory

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Abstract

The activation of NO by oxygen is a crucial step in the selective catalytic reduction of NO by NH3 over Cu-CHA catalysts. In this article, the transition states and activation energies for this activation on isolated and neighboring Cu ions are compared by density functional theory calculations, using the nudged elastic band method. For isolated Cu ions, oxygen can be adsorbed both “side-on” and “end-on”. The “end-on” configuration of oxygen reacts with NO to bidentate nitrate via sequential incorporation of the oxygen atoms; the activation energy for this reaction is +1.17 eV. Adsorption of oxygen on two neighboring Cu ions is very favorable, with an adsorption energy of −1.37 eV. Adsorption of NO leads to dissociation of the O–O bond and an NO2 species is formed on each Cu ion. The activation energy for this reaction (0.60 eV) is lower than that for the activation on isolated Cu ions. This indicates that the SCR reaction on two neighboring Cu ions is faster, which can account for an increased TOF with increasing Cu load in a Cu-CHA zeolite.

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References

  1. Nova I, Tronconi E (2014) Urea-SCR technology for deNOx after treatment of diesel exhausts. Springer. doi:10.1007/978-1-4899-8071-7

    Google Scholar 

  2. Vennestrøm PNR, Katerinopoulou A, Tiruvalam RR et al (2013) Migration of Cu ions in SAPO-34 and its impact on selective catalytic reduction of NOx with NH3. ACS Catal 3:2158–2161. doi:10.1021/cs400499p

    Article  Google Scholar 

  3. Kwak JH, Tonkyn RG, Kim DH et al (2010) Excellent activity and selectivity of Cu-SSZ-13 in the selective catalytic reduction of NOx with NH3. J Catal 275:187–190. doi:10.1016/j.jcat.2010.07.031

    Article  CAS  Google Scholar 

  4. Kwak JH, Tran D, Burton SD et al (2012) Effects of hydrothermal aging on NH3-SCR reaction over Cu/zeolites. J Catal 287:203–209. doi:10.1016/j.jcat.2011.12.025

    Article  CAS  Google Scholar 

  5. Kieger S, Delahay G, Coq B, Neveu B (1999) Selective catalytic reduction of nitric oxide by ammonia over Cu-FAU catalysts in oxygen-rich atmosphere. J Catal 183:267–280

    Article  CAS  Google Scholar 

  6. Paolucci C, Verma AA, Bates SA et al (2014) Isolation of the copper redox steps in the standard selective catalytic reduction on Cu-SSZ-13. Angew Chem Int Ed 53:11828–11833. doi:10.1002/anie.201407030

    Article  CAS  Google Scholar 

  7. Janssens TVW, Falsig H, Lundegaard LF et al (2015) A consistent reaction scheme for the selective catalytic reduction of nitrogen oxides with ammonia. ACS Catal 5:2832–2845. doi:10.1021/cs501673g

    Article  CAS  Google Scholar 

  8. Gao F, Walter ED, Kollar M et al (2014) Understanding ammonia selective catalytic reduction kinetics over Cu/SSZ-13 from motion of the Cu ions. J Catal 319:1–14. doi:10.1016/j.jcat.2014.08.010

    Article  CAS  Google Scholar 

  9. Wellendorff J, Lundgaard KT, Møgelhøj A et al (2012) Density functionals for surface science: exchange-correlation model development with Bayesian error estimation. Phys Rev B 85:235149. doi:10.1103/PhysRevB.85.235149

    Article  Google Scholar 

  10. Brogaard RY, Moses PG, Nørskov JK (2012) Modeling van der Waals interactions in zeolites with periodic DFT: physisorption of n-alkanes in ZSM-22. Catal Lett 142:1057–1060. doi:10.1007/s10562-012-0870-9

    Article  CAS  Google Scholar 

  11. Henkelman G, Uberuaga BP, Jónsson H (2000) A climbing image nudged elastic band method for finding saddle points and minimum energy paths. J Chem Phys 113:9901–9904

    Article  CAS  Google Scholar 

  12. McEwen J-S, Anggara T, Schneider WF et al (2012) Integrated operando X-ray absorption and DFT characterization of Cu–SSZ-13 exchange sites during the selective catalytic reduction of NOx with NH3. Catal Today 184:129–144. doi:10.1016/j.cattod.2011.11.037

    Article  CAS  Google Scholar 

  13. Verma AA, Bates SA, Anggara T et al (2014) NO oxidation: a probe reaction on Cu-SSZ-13. J Catal 312:179–190. doi:10.1016/j.jcat.2014.01.017

    Article  CAS  Google Scholar 

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Authors and Affiliations

  1. Haldor Topsoe A/S, Haldor Topsøes Allé 1, 2800, Kongens Lyngby, Denmark

    Hanne Falsig, Peter N. R. Vennestrøm, Poul Georg Moses & Ton V. W. Janssens

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  1. Hanne Falsig
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  2. Peter N. R. Vennestrøm
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  3. Poul Georg Moses
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  4. Ton V. W. Janssens
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Correspondence to Ton V. W. Janssens.

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Falsig, H., Vennestrøm, P.N.R., Moses, P.G. et al. Activation of Oxygen and NO in NH3-SCR over Cu-CHA Catalysts Evaluated by Density Functional Theory. Top Catal 59, 861–865 (2016). https://doi.org/10.1007/s11244-016-0560-8

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  • DOI: https://doi.org/10.1007/s11244-016-0560-8

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