PMID- 16471552 OWN - NLM STAT- MEDLINE DCOM- 20060821 LR - 20131121 IS - 1520-6106 (Print) IS - 1520-5207 (Linking) VI - 110 IP - 1 DP - 2006 Jan 12 TI - In situ studies of the active sites for the water gas shift reaction over Cu-CeO2 catalysts: complex interaction between metallic copper and oxygen vacancies of ceria. PG - 428-34 AB - New information about the active sites for the water gas shift (WGS) reaction over Cu-CeO2 systems was obtained using in-situ, time-resolved X-ray diffraction (TR-XRD), X-ray absorption spectroscopy (TR-XAS, Cu K and Ce L3 edges), and infrared spectroscopy (DRIFTS). Cu-CeO2 nanoparticles prepared by a novel reversed microemulsion method (doped Ce1-xCuxO2 sample) and an impregnation method (impregnated CuOx/CeO2 sample) were studied. The results from all of the samples indicate that both metallic copper and oxygen vacancies in ceria were involved in the generation of active sites for the WGS reaction. Evidence was found for a synergistic Cu-Ovacancy interaction. This interaction enhances the chemical activity of Cu, and the presence of Cu facilitates the formation of O vacancies in ceria under reaction conditions. Water dissociation occurred on the Ovacancy sites or the Cu-Ovacancy interface. No significant amounts of formate were formed on the catalysts during the WGS reaction. The presence of strongly bound carbonates is an important factor for the deactivation of the catalysts at high temperatures. This work identifies for the first time the active sites for the WGS reaction on Cu-CeO2 catalysts and illustrates the importance of in situ structural studies for heterogeneous catalytic reactions. FAU - Wang, Xianqin AU - Wang X AD - Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA. FAU - Rodriguez, Jose A AU - Rodriguez JA FAU - Hanson, Jonathan C AU - Hanson JC FAU - Gamarra, Daniel AU - Gamarra D FAU - Martinez-Arias, Arturo AU - Martinez-Arias A FAU - Fernandez-Garcia, Marcos AU - Fernandez-Garcia M LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, Non-P.H.S. PL - United States TA - J Phys Chem B JT - The journal of physical chemistry. B JID - 101157530 RN - 059QF0KO0R (Water) RN - 30K4522N6T (Cerium) RN - 619G5K328Y (ceric oxide) RN - 789U1901C5 (Copper) RN - S88TT14065 (Oxygen) SB - IM MH - Catalysis MH - Cerium/*chemistry MH - Copper/*chemistry MH - Oxidation-Reduction MH - Oxygen/*chemistry MH - Sensitivity and Specificity MH - Spectroscopy, Fourier Transform Infrared/methods MH - Temperature MH - Time Factors MH - Water/*chemistry MH - X-Ray Diffraction EDAT- 2006/02/14 09:00 MHDA- 2006/08/22 09:00 CRDT- 2006/02/14 09:00 PHST- 2006/02/14 09:00 [pubmed] PHST- 2006/08/22 09:00 [medline] PHST- 2006/02/14 09:00 [entrez] AID - 10.1021/jp055467g [doi] PST - ppublish SO - J Phys Chem B. 2006 Jan 12;110(1):428-34. doi: 10.1021/jp055467g.