CO Oxidation on Inverse CeOx/Cu(111) Catalysts: High Catalytic Activity and Ceria-Promoted Dissociation of O2

Journal Article · Sat Dec 31 04:00:00 EST 2011 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja1087979· OSTI ID:1041905

Yang, F; Graciani, J; Evans, J; Liu, P; Hrbek, J; Sanz, J Fdez; Rodriguez, J

A Cu(111) surface displays a low activity for the oxidation of carbon monoxide (2CO + O{sub 2} {yields} 2CO{sub 2}). Depending on the temperature, background pressure of O{sub 2}, and the exposure time, one can get chemisorbed O on Cu(111) or a layer of Cu{sub 2}O that may be deficient in oxygen. The addition of ceria nanoparticles (NPs) to Cu(111) substantially enhances interactions with the O{sub 2} molecule and facilitates the oxidation of the copper substrate. In images of scanning tunneling microscopy, ceria NPs exhibit two overlapping honeycomb-type moire structures, with the larger ones (H{sub 1}) having a periodicity of 4.2 nm and the smaller ones (H{sub 2}) having a periodicity of 1.20 nm. After annealing CeO{sub 2}/Cu(111) in O{sub 2} at elevated temperatures (600-700 K), a new phase of a Cu{sub 2}O{sub 1+x} surface oxide appears and propagates from the ceria NPs. The ceria is not only active for O{sub 2} dissociation, but provides a much faster channel for oxidation than the step edges of Cu(111). Exposure to CO at 550-750 K led to a partial reduction of the ceria NPs and the removal of the copper oxide layer. The CeO{sub x}/Cu(111) systems have activities for the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction that are comparable or larger than those reported for surfaces of expensive noble metals such as Rh(111), Pd(110), and Pt(100). Density-functional calculations show that the supported ceria NPs are able to catalyze the oxidation of CO due to their special electronic and chemical properties. The configuration of the inverse oxide/metal catalyst opens new interesting routes for applications in catalysis.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1041905
• Report Number(s): BNL--97583-2012-JA
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 10 Vol. 133; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ANNEALING
CARBON MONOXIDE
CATALYSIS
CATALYSTS
CHEMICAL PROPERTIES
CONFIGURATION
COPPER
COPPER OXIDES
DISSOCIATION
OXIDATION
OXIDES
OXYGEN
PERIODICITY
REMOVAL
SCANNING TUNNELING MICROSCOPY