CO chemisorption over MnO/sub x/-modified Ni(111): importance of perimeter sites in strong metal-support interaction

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · J. Catal.; (United States)

OSTI ID:5206148

Zhao, Y B; Chung, Y W

CO chemisorption on both clean Ni(111) and MnO/sub x/ (x is between 0.2 and 0.5)-modified Ni(111) surfaces at 200/sup 0/K have been studied by Auger electron spectroscopy (AES), thermal desorption spectroscopy (TDS), and high-resolution electron energy loss spectroscopy (HREELS). The MnO/sub x/Ni specimen was prepared by evaporating MnO/sub 2/ powder to the Ni surface and then reducing the specimen at 700/sup 0/K. TDS results showed that the presence of surface MnO/sub x/ species suppresses CO chemisorption and that the suppression is almost a linear function of the MnO/sub x/ coverage. The most prominent CO desorption peak on Ni occurs at 415/sup 0/K. This peak intensity decreased with increasing MnO/sub x/ coverage, indicating a site-blocking effect. An additional CO desorption peak at 305/sup 0/K was found on the MnO/sub x/-modified Ni surface. This 305/sup 0/K peak intensity attains a maximum at some intermediate MnO/sub x/ coverage. HREELS showed a new C-O stretching frequency of 1620 cm/sup -1/ for CO adsorbed on the MnO/sub x/Ni surface. The disappearance of this 1620-cm/sup -1/ energy loss peak upon heating the surface to 325/sup 0/K suggests that both the 305/sup 0/K TDS peak and 1620-cm/sup -1/ energy loss peak represent the same adsorbed CO state, which is attributed to CO adsorbed on MnO/sub x/Ni perimeter sites. Surface morphology of the oxide islands and significance of the perimeter sites are discussed along with experimental results. 42 references

• Research Organization: Northwestern Univ., Evanston, IL (USA)
• OSTI ID: 5206148
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 106:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010408* -- Coal
Lignite
& Peat-- C1 Processes-- (1987-)
ADSORPTION
AUGER ELECTRON SPECTROSCOPY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DESORPTION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY-LOSS SPECTROSCOPY
HYDROGENATION
KINETICS
MANGANESE COMPOUNDS
MANGANESE OXIDES
METALS
METHANATION
NICKEL
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
SURFACE PROPERTIES
SYNTHESIS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS