Regeneration of Cu/SAPO-34(MO) with H2O only: Too good to be true?
Journal article, 2020

The performance failure of Cu/SAPO-34 material used as an NH3-SCR catalyst at low temperature in the presence of water has caused a gradual withdrawal of its usage from the market. There is an urgent need to clearly understand its deactivation mechanism and to find a way to regenerate the Cu/SAPO-34 catalyst material. Interestingly and surprisingly, we have discovered that, under certain conditions, 10% H2O can regenerate a previously deactivated Cu/SAPO-34(MO), as long as its zeolite structure is maintained. By using experimental observations of NH3-SCR reaction, solid state NMR, NO-DRIFTS, and in situ H2-TPR, a mechanism is proposed which can explain both the deactivation and regeneration of Cu/SAPO-34(MO). We propose that the transformation of Si(4OAl) and Si(3OAl) to (2Al)Si(2OH) and (3Al)Si(OH) and the Si condensation in the pores of the framework, which result from H2O exposure, are responsible for the deactivation of Cu/SAPO-34(MO). We suggest that the formation of condensed Si which results in Si clusters, hinders the mobility of the linear complex, [Cu-(NH3)2]+, which is the active species during the low temperature NH3-SCR reaction. Moreover, we propose a regeneration mechanism when Cu/SAPO-34(MO) is exposed to 10% H2O, where the Si clusters are transformed back to Si-O-H bonds, and thereafter transferred back to the framework. This can explain the regeneration of deactivated Cu/SAPO-34(MO).

Author

Jung Won Woo

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Engineering Design

Diana Bernin

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Engineering Design

Homayoun Ahari

FCA US LLC

Mark Shost

FCA US LLC

Michael Zammit

FCA US LLC

Louise Olsson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology

Catalysis Science and Technology

2044-4753 (ISSN) 2044-4761 (eISSN)

Vol. 10 5 1529-1538

New methodology for fundamental kinetic models in heterogeneous catalysis using inter-disciplinary experiments

Swedish Research Council (VR), 2014-01-01 -- 2019-12-31.

Subject Categories

Inorganic Chemistry

Materials Chemistry

Organic Chemistry

DOI

10.1039/c9cy01981b

More information

Latest update

4/22/2020