Characterization of silica-supported Cu monometallic and Ru-Cu bimetallic catalysts by hydrogen chemisorption and NMR of adsorbed hydrogen

Journal Article · Thu Feb 01 00:00:00 EST 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(90)90237-E· OSTI ID:6437759

Wu, X; Gerstein, B C; King, T S ^[1]

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1. Iowa State Univ., Ames (USA)

Monometallic Ru/SiO{sub 2} and Cu/SiO{sub 2} catalysts and a series of Ru-Cu/SiO{sub 2} bimetallic catalysts were investigated in detail by hydrogen chemisorption and nuclear magnetic resonance (NMR) of adsorbed hydrogen. NMR indicates that adsorption of hydrogen on pure Cu/SiO{sub 2} at room temperature results in formation of a mobile, atom-like adsorbed species. Hydrogen spillover from Ru to Cu in the Ru-Cu/SiO{sub 2} bimetallic catalysts was clearly shown by the two techniques. Two distinct adsorbed states of hydrogen were observed on surfaces of the Ru-Cu bimetallic particles. One state is reversibly adsorbed at room temperature while the other is irreversibly adsorbed. The reversible hydrogen exhibits rapid motion at the surface; the irreversible hydrogen is less mobile. Surface compositions for all the Ru-Cu/SiO{sub 2} bimetallic catalysts were obtained from the NMR resonance lineshifts of the reversible hydrogen. The results show a preferential segregation of Cu to surfaces of Ru particles and indicate formation of large Cu islands on ruthenium and separate pure Cu particles at very high copper loadings. 55 refs.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6437759
• Journal Information: Journal of Catalysis; (USA), Vol. 121:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BIMETALS
SURFACE PROPERTIES
COPPER
HYDROGEN
CHEMISORPTION
RUTHENIUM
AMBIENT TEMPERATURE
CATALYSIS
CATALYST SUPPORTS
NUCLEAR MAGNETIC RESONANCE
SILICON OXIDES
SORPTIVE PROPERTIES
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
MAGNETIC RESONANCE
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RESONANCE
SEPARATION PROCESSES
SILICON COMPOUNDS
SORPTION
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties