Activation of oxygen on (NH3–Cu–NH3)+ in NH3-SCR over Cu-CHA
Journal article, 2018

Cu-CHA materials are efficient catalysts for NH 3 –SCR of NO x in oxygen excess. A crucial step in the reaction is oxygen (O 2 ) activation, which still is not well understood. Density functional theory calculations in combination with ab initio thermodynamics and molecular dynamics are here used to study O 2 dissociation on Cu(NH 3 ) 2 + species, which are present under NH 3 –SCR conditions. Direct dissociation of O 2 is found to be facile over a pair of Cu(NH 3 ) 2 + complexes whereas dissociation on a single Cu(NH 3 ) 2 + species is unlikely due to a high activation energy. The presence of NO promotes oxygen dissociation on both single and pairs of Cu(NH 3 ) 2 + complexes. Nitrites and nitrates are easily formed as O 2 dissociates, and NO adsorption over nitrates leads to facile formation of NO 2 . The results stress the importance of ligand-stabilized Cu species in Cu-CHA catalysts for NH 3 –SCR.

O2-activation

DFT

Cu diamine complex

Chabazite

NH3–SCR

Author

Lin Chen

Hanne Falsig

Haldor Topsoe

Ton Janssens

Haldor Topsoe

Henrik Grönbeck

Chalmers, Physics, Chemical Physics

Competence Centre for Catalysis (KCK)

Journal of Catalysis

0021-9517 (ISSN) 1090-2694 (eISSN)

Vol. 358 179-186

Subject Categories

Inorganic Chemistry

Other Chemistry Topics

Organic Chemistry

DOI

10.1016/j.jcat.2017.12.009

More information

Latest update

3/29/2018