Characterization of silica-supported ruthenium catalysts by hydrogen chemisorption and nuclear magnetic resonance of adsorbed hydrogen

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90314-X· OSTI ID:7257737

Wu, X; Gerstein, B C; King, T S ^[1]

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1. Iowa State Univ., Ames (USA)

Adsorbed hydrogen on four silica-supported ruthenium catalysts was measured quantitatively by proton magnetic resonance (PMR). The PMR technique revealed two distinct adsorbed states of hydrogen on the metal: reversible and irreversible. The results from PMR and those from conventional hydrogen chemisorption measurements were compared directly. The observed discrepancy between the PMR and volumetric techniques in the case of total adsorption is attributed to spillover of reversibly adsorbed hydrogen from ruthenium onto the silica support. Good agreement was obtained between the two techniques in the case of irreversible adsorption. The relatively narrow line of PMR spectra on the reversibly adsorbed hydrogen indicates rapid motion for this state of hydrogen on ruthenium surfaces. The variation of spectral lineshift and of the spin-lattice relaxation times for the adsorbed hydrogen with ruthenium particle size suggests a stronger interaction between the adsorbed hydrogen and defect-like ruthenium adsorption sites. The results from PMR intensity measurements also suggest that the reversibly adsorbed hydrogen is at least in part associated with the defect-like ruthenium adsorption sites.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7257737
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 118:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CATALYST SUPPORTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
ELEMENTS
HYDROGEN
MAGNETIC RESONANCE
METALS
MINERALS
NONMETALS
NUCLEAR MAGNETIC RESONANCE
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PLATINUM METALS
RELAXATION
RESONANCE
RUTHENIUM
SEPARATION PROCESSES
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SIZE
SORPTION
SPIN-LATTICE RELAXATION
SURFACE PROPERTIES
TRANSITION ELEMENTS