Web Release Date: October 24,
Deactivation Mechanism of a Au/CeZrO4 Catalyst During a Low-Temperature Water Gas Shift Reaction
and
CenTACat and School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, Northern Ireland, United Kingdom, Advanced Light Source, Berkeley Lab, 1 Cyclotron Road, Berkeley, California 94720, and Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, United Kingdom
Received: June 7, 2007
In Final Form: September 4, 2007
Abstract:
On-stream deactivation during a water gas shift (WGS) reaction over gold supported on a ceria-zirconia
catalyst was examined. Although the fresh catalyst has very high low temperature (<200 
C) for WGS activity,
a significant loss of CO conversion is found under steady-state operations over hours. This has been shown
to be directly related to the concentration of water in the gas phase. The same catalyst also undergoes thermal
deactivation above 250 C, and using a combined experimental and theoretical approach, a common deactivation
mechanism is proposed. In both cases, the gold nanoparticles, which are found under reaction conditions, are
thought to detach from the oxide support either through hydrolysis, <250 C, or thermally, >250 C. This
process reduces the metal-support interaction, which is considered to be critical in determining the high
activity of the catalyst.
Download the full text: PDF | HTML
