1H and 129Xe nuclear magnetic resonance studies of hydrogen chemisorption on supported platinum. Application to the metal dispersion and spillover.
Chemisorption of hydrogen, electron microscopy and 1H nuclear magnetic resonance (NMR) have confirmed that the chemical shift of hydrogen chemisorbed on platinum is directly related to the size of the metal particles. The influence of the hydrogen adsorbate concentration and the chemisorption temperature on the chemical shift delta H and the distribution of the hydrogen chemisorbed on these particles have been determined. This study also shows how the dispersion can be deduced from the variation of delta H with the H2 concentration and clarifies the effect of temperature on the concentration of spillover H2. 129Xe NMR of adsorbed xenon used as a probe confirmed most of the previous results.
Rouabah
D
D
Laboratoire de Chimie des Surfaces, Associé au CNRS URA 1428, Université Pierre et Marie Curie, Paris, France.
Fraissard
J
J
D000327:Adsorption; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D010316:Particle Size; D010984:Platinum; D013696:Temperature; D014978:Xenon
D014978:Xenon; D010984:Platinum; D006859:Hydrogen