Development and Assessment of Regeneration Methods for Commercial Automotive Three-Way Catalysts

Car exhaust catalysts were introduced in the early
1980 s, to limit the release of pollutants such as
hydrocarbons, carbon monoxide and nitrogen oxides.
These catalysts contain noble metals such as
palladium (Pd), platinum (Pt) and rhodium (Rh) and
are able to simultaneously abate all three of the
above-mentioned pollutants, hence the name three-way
catalyst (TWC). The exposure to high temperatures
(800-1000 °C) during operation and the presence of
additives in gasoline and lubricants will, after a
certain time, lower the activity of the TWC. High
temperatures reduce the active area by causing the
noble metals to agglomerate and sinter, whereas the
additives alter the activity either by fouling the
pores of the support material or by interacting with
the metals.

The main objective of this work was to develop a
method which allows for the removal of contaminants
(additives) from the washcoat and enables the
redispersion of the active sites (noble metals), in
an effort to recover lost catalyst activity. For
this purpose, regeneration experiments were carried
out on a wide spectrum of different commercial car
exhaust catalysts.

Autorentext
Henrik Birgersson
b. 1976 in Stockholm, Sweden
M.Sc. (Chem. Eng.) 2001
Royal Institute of Technology, Stockholm
Ph.D. (Chem. Eng.) 2006 Department of Chemical Engineering
Royal Institute of Technology, Stockholm
Since 2006 working at Scania CV AB as a development engineer at
the Advanced Aftertreatment Engine Department

Klappentext
Car exhaust catalysts were introduced in the early 1980's, to limit the release of pollutants such as hydrocarbons, carbon monoxide and nitrogen oxides. These catalysts contain noble metals such as palladium (Pd), platinum (Pt) and rhodium (Rh) and are able to simultaneously abate all three of the above-mentioned pollutants, hence the name three-way catalyst (TWC). The exposure to high temperatures (800-1000 °C) during operation and the presence of additives in gasoline and lubricants will, after a certain time, lower the activity of the TWC. High temperatures reduce the active area by causing the noble metals to agglomerate and sinter, whereas the additives alter the activity either by fouling the pores of the support material or by interacting with the metals. The main objective of this work was to develop a method which allows for the removal of contaminants (additives) from the washcoat and enables the redispersion of the active sites (noble metals), in an effort to recover lost catalyst activity. For this purpose, regeneration experiments were carried out on a wide spectrum of different commercial car exhaust catalysts.