BASIC STUDY OF GAS-SOLID INTERACTIONS: I. INTERACTION OF HYDROGEN WITH PLATINIZED CARBON.
LOCKHEED MISSILES AND SPACE CO SUNNYVALE CALIF
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It has been confirmed that the dispersion of platinum on the surface of Spheron-6 carbon increases the adsorption of hydrogen, both in rate and in amount. This excess adsorption, which is too great to be accounted for by the platinum alone, has been measured at 300 to 392 degrees C, at pressures from 30 to 60 cm Hg, and at Pt contents of 0.2 percent and 1.0 percent by weight. The observed dependence of the excess adsorption on these variables and the results of deuterium adsorptions point to a mechanism pictured as follows Hydrogen adsorbs and dissociates quickly on the Pt. Around the Pt a zone is established which is in equilibrium with the gas phase. This zone acts as a source for surface diffusion of H atoms along the carbon surface. Alternate mechanisms are discussed and rejected. The proposed model is described quantitatively and adequate agreement is obtained with experiment. Within the framework of the model, the activation energy for surface diffusion is 39.2 kcalg-atom H, and the surface diffusion coefficient at 392C is 5.77 times 10 to the -17th power sq cmsec. Author