Interaction of hydrogen with supported Ru catalysts: High pressure in situ NMR studies

Journal Article · Wed Jun 01 04:00:00 EDT 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1162· OSTI ID:7275832

Bhatia, S; Engelke, F; Pruski, M; Gerstein, B C; King, T S ^[1]

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1. Iowa State Univ., Ames, IA (United States)

An in situ H nuclear magnetic resonance (NMR) technique has been employed to study the interaction of hydrogen with silica-supported ruthenium catalysts in the temperature range 300-473 K and at pressures of 10[sup [minus]5]-760 Torr. In addition to an upfield NMR peak (called [alpha]) occurring at [approximately] [minus]60 ppm and observed at low pressures (P < 100 Torr), the authors have noted the emergence of a second peak (called [beta]) occurring at [approximately] [minus]30 ppm at elevated pressures (P > 100 Torr). These two hydrogen populations represent adsorbed hydrogen interacting with Ru metal particles, as indicated by the observed Knight shifts. The [alpha] hydrogen species exists in the form of less mobile hydrogen species [alpha][sub 1], or a mobile hydrogen species [alpha][sub M] with heats of adsorption determined by microcalorimetry to be about 70 kJ/mol and 40 kJ/mol, respectively. The heat of adsorption of the [beta] species was determined to be approximately 10 kJ/mol. Hydrogen adsorption isotherms were obtained from the NMR peak intensities calibrated by a gadolinium-doped lanthanum hydride internal reference. A higher dispersion of metal particles correlated with a larger amount of the weakly adsorbed [beta] hydrogen species. The H/Ru[sub surface] ratio was observed to be in excess of 5 at elevated pressures (>500 Torr). The high H/Ru[sub surface] was due to the adsorption of large amounts of [beta] hydrogen. 53 refs., 9 figs., 1 tab.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7275832
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 147:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ADSORPTION HEAT
ADSORPTION ISOTHERMS
CALORIMETRY
CATALYST SUPPORTS
CHALCOGENIDES
ELEMENTS
ENTHALPY
HIGH VACUUM
HYDROGEN
ISOTHERMS
LOW PRESSURE
MAGNETIC RESONANCE
METALS
MINERALS
NONMETALS
NUCLEAR MAGNETIC RESONANCE
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
PRESSURE DEPENDENCE
RESONANCE
RUTHENIUM
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS