In situ Raman spectroscopy evidence of an accessible phase potentially involved in the enhanced activity of La -deficient lanthanum orthoferrite in 3-way catalysis (TWC)

We report here on an in situ Raman investigation of stoichiometric and La-deficient LaFeO3 solids along model treatments related to three-way catalysis. Whereas the Raman signature of the stoichiometric compound is only slightly modified by the sequence we have applied, the reversible formation of a new phase based on FeTO3 in the La-deficient solid was evidenced. This new phase was found to be stabilized under the same experimental conditions which also favor the volumetric expansion of the LFO unit cell. Eventually, this new iron oxide phase was found to be reduced under CO/He mixture and subsequently regenerated under NO. (C) 2016 Elsevier B.V. All rights reserved.