Comparative studies of low-temperature water–gas shift reaction over Pt=CeO 2 , Au=CeO 2 , and Au=Fe 2 O 3 catalysts Apanee Luengnaruemitchai a , Somchai Osuwan a, * , Erdogan Gulari b a ThePetroleumandPetrochemicalCollege,ChulalongkornUniversity,Bangkok10330,Thailand b DepartmentofChemicalEngineering,UniversityofMichigan,AnnArbor,MI,USA Received 27 September 2002; received in revised form 3 March 2003; accepted 13 March 2003 Abstract We studied catalytic low-temperature water–gas shift (WGS) reaction over the Pt=CeO 2 , Au=CeO 2 and Au=Fe 2 O 3 catalysts. The activity of these catalysts was tested in the composition of 4% CO, 2.6–20% H 2 O and helium in the range of 120–360 °C. It was found that CO and H 2 O concentrations have significant effects on the catalytic activity. The 1% Pt=CeO 2 was substantially more active than other catalysts in the presence of 20% H 2 O. The catalytic activity of these catalysts was compared in the presence of H 2 and deactivation test was also performed. BET, XRD, SEM and TEM analyses give additional information on the morphological structure of investigated samples. Ó 2003 Elsevier Science B.V. All rights reserved. Keywords: Water–gas shift reaction; Platinum; Gold; Ceria; Ferric oxide 1. Introduction Polymer electrolyte fuel cells (PEFC) are at- tractive for use in transportation applications. H 2 produced from on board steam reforming of gas- oline and diesel fuel is the most logical means powering the PEFCs. However, the H 2 produced from reformed gas contains  10% CO. In general, water–gas shift (WGS) reaction is the preferred reaction for CO removal. Conversion of CO by the water gas shift (Eq. (1)) increases the hydrogen yield as well as getting reducing the CO concen- tration from  10% to  0:5–1% [1]. CO þ H 2 O ! CO 2 þ H 2 ; DH ¼41:1 kJ mol 1 ð1Þ There are two types of WGS catalysts which are commercially used. One is a high temperature shift catalyst, which consists of oxides of iron and chromium and is used at 400–500 °C to reduce the carbon monoxide to around 2–5%. The second one is a low temperature shift catalyst composed of copper, zinc oxide and alumina normally used between 200 and 400 °C to reduce the CO con- centration to  1%. The thermodynamics of the Catalysis Communications 4 (2003) 215–221 www.elsevier.com/locate/catcom * Corresponding author. Tel.: +662-2184141-2; fax: +662- 2154459. E-mailaddress: somchai.o@chula.ac.th (S. Osuwan). 1566-7367/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S1566-7367(03)00036-0