Deuterium adsorption

STUDY OF ISOTOPIC EFFECT FOR HYDROGEN AND DEUTERIUM ADSORPTION ON NANOPOROUS CARBON (NPC) AT 67-78 K... 

Form of protium and deuterium adsorption isotherms on the sample of nanoporous carbon are similar to ones on activated carbon and zeolites. They comparison is shown in figure 3. You can see that adsorption capacity of the NPC samples is larger than one on common sorbents such as zeolites [10-11] and it is close to active carbon [12]. 

As the temperature of activation increases, the catalytic behavior in reactions between deuterium and olefins simplifies markedly. On amorphous catalysts activated at 400° or above, only simple cis addition and deuterium adsorption remain significant. Since processes which would put atoms of protium on the surface have become very slow, the relative rate of desorption of HD cannot be diagnosed directly. 

Fig. 1.30. Mass spectra of platinum clusters Ptn before and after reaction with O2 and D2. In the upper mass spectrum (a) no reaction gas was added to the collision gas cells (cf. Fig. 1.29). Spectrum (b) was obtained with 0.14Pa O2 in reaction cell 1 and no gas in reaction cell 2. Spectrum (c) was sampled after the metal cluster beam passed cell 1 with 0.14 Pa O2 and cell 2 with a deuterium pressure of 0.95 Pa. Note that the mass peaks in (c) are slightly broader and exhibit a small shift with respect to mass spectrum (a). This is due to multiple deuterium adsorption onto the platinum clusters which can, however, not be resolved in the mass spectrum [169]...

Belysheva et al. determined the equilibrium constants for the reactions CO + 2H2 MeOH (Kj) and CO + 2D2 CH3OD (K2). They found log (K2/K1) = 194/T + 0.4689. Belysheva et al. reported that the rate of synthesis of CD3OD from CO and D2 using a Zn0-Cr203 or Cu-Zn0-Cr203 catalyst exceeded that of the formation of CH3OH from CO and H2. They concluded that hydrogen (deuterium) adsorption is the RDS. 

Fig. 27. The site-blocking effect of sulfur on deuterium adsorption on Mo(lOO) as determined by deuterium thermal desorption. (0) = sulfur layer disordered, (x) = sulfur layer ordered. The broken line is a theoretical prediction of the site-blocking effect assuming that one sulfur atom blocks one deuterium atom adsorption site and that deuterium molecules chemisorb dissociatively in adjacent, unoccupied sites...

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