Nuclear magnetic resonance of hydrogen sorbed by powdered palladium metal and alumina-supported palladium.
Hydrogen in 0.2 micron beta-palladium powder and in an alumina-supported palladium catalyst was investigated by NMR spectroscopy. The dependence of the shift on hydrogen pressure and the hydrogen-to-palladium (H/Pd) ratio in beta-palladium hydride was determined for 273 K < T < 368 K. The activation energy for the process affecting the hydrogen shift is 9.4(+/- 0.5) kcal mol-1, similar to the enthalpy of transition from the alpha- to beta-phase. NMR measurements of hydrogen in alumina-supported palladium show a similar behavior, which may allow one to use NMR shifts as a barometer of the state of the hydrogen in the metal.
Department of Chemistry and Biochemistry, University of Delaware, Newark 19716.
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Barabino
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Dybowski
D000327:Adsorption; D000537:Aluminum Oxide; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010165:Palladium / Q000737:chemistry*; D011208:Powders; D011312:Pressure; D011522:Protons; D013696:Temperature; D013816:Thermodynamics
D011208:Powders; D011522:Protons; D010165:Palladium; D006859:Hydrogen; D000537:Aluminum Oxide