Operando Spectroscopic Studies of Cu-SSZ-13 for NH3-SCR deNOx Investigates the Role of NH3 in Observed Cu(II) Reduction at High NO Conversions

Alex G Greenaway; Ines Lezcano-Gonzalez; Miren Agote-Aran; Emma K Gibson; Yaroslav Odarchenko; Andrew M Beale

doi:10.1007/s11244-018-0888-3

Operando Spectroscopic Studies of Cu-SSZ-13 for NH₃-SCR deNOx Investigates the Role of NH₃ in Observed Cu(II) Reduction at High NO Conversions

Top Catal. 2018;61(3):175-182. doi: 10.1007/s11244-018-0888-3. Epub 2018 Jan 19.

Authors

Alex G Greenaway^{1

2}, Ines Lezcano-Gonzalez^{1

2}, Miren Agote-Aran^{1

2}, Emma K Gibson^{1

2}, Yaroslav Odarchenko^{1

2}, Andrew M Beale^{1

2}

Affiliations

¹ 1Department of Chemistry, UCL, 20 Gordon Street, London, WC1H 0AJ UK.
² 2Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell, Didcot, OX11 0FA UK.

Abstract

The small pore zeolite chabazite (SSZ-13) in the copper exchanged form is a very efficient material for the selective catalytic reduction by ammonia (NH₃) of nitrogen oxides (NOx) from the exhaust of lean burn engines, typically diesel powered vehicles. The full mechanism occurring during the NH₃-SCR process is currently debated with outstanding questions including the nature and role of the catalytically active sites. Time-resolved operando spectroscopic techniques have been used to provide new level of insights in to the mechanism of NH₃-SCR, to show that the origin of stable Cu(I) species under SCR conditions is potentially caused by an interaction between NH₃ and the Cu cations located in eight ring sites of the bulk of the zeolite and is independent of the NH₃-SCR of NOx occurring at Cu six ring sites within the zeolite.

Keywords: Catalysis; Cu–SSZ-13; Operando; XANES; Zeolite.