Deactivation and regeneration of spent three-way automotive exhaust gas catalysts (TWC)
2004 (English)In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 30-1, no 1-4, 433-437 p.Article in journal (Refereed) Published
The effect of oxidation, oxy-chlorination and reduction treatments at elevated temperatures on the dispersion of palladium (Pd) and rhodium (Rh) for commercially aged three-way automotive exhaust gas catalysts (TWC) has been investigated. The catalytic activity of treated samples was compared with a reference sample, which was taken from the corresponding aged TWC and tested using a 'mini-cuts' reactor simulating real driving conditions. In the case of oxygen, the improvement of the noble metal dispersion on the catalysts was dependent on the noble metal loading and the degree of metal sintering. Adding chlorine to the oxygen atmosphere facilitates the restructuring of the metals with an improved increase in the noble metal dispersion. The temperature and the composition of the gas used during these thermal treatments proved to be of importance not only to increase the metal dispersion, but also to prevent possible losses of noble metals, in the form of volatile MOxCly compounds. TEM-EDS techniques indicated changes in the size of the largest noble metal agglomerates of Lip to 100 nm in size after thermal gas treatment. BET porosity and XRD analyses were employed to investigate restructuring of the washcoat and showed a decrease in pore size distribution and an increase in surface area.
Place, publisher, year, edition, pages
2004. Vol. 30-1, no 1-4, 433-437 p.
automotive catalyst, thermal gas treatment, chlorine effects, regeneration, dispersion, chlorine-containing gases, metal-catalysts, redispersion, particles, platinum, sio2, crystallites, gamma-al2o3, oxidation
IdentifiersURN: urn:nbn:se:kth:diva-23566DOI: 10.1023/B:TOCA.0000029786.49989.aaISI: 000222595000068ScopusID: 2-s2.0-3042825288OAI: oai:DiVA.org:kth-23566DiVA: diva2:342264
QC 20100525 QC 20111018. 6th International Congress on Catalysis and Automotive Pollution Control (CAPoC6). Brussels, BELGIUM. OCT 22-24, 20032010-08-102010-08-102011-10-18Bibliographically approved