Kinetics of the Isothermal Decomposition of Lanthanum Nickel Hydride*

Kinetics of hydrogen absorption and desorption in LaNi5‐xAlx slurries

“…Apparently, the hydrogen atoms are not hindered by the solvent molecules when they recombine on the surface and desorb into the gas phase. The liquid molecules on the surface are bypassed, as was already suggested by Reilly et al (1989). During desorption no influence of the solvent is to be expected, which was confirmed by the experiments with LaNi, in ethanol and cyclohexane.…”

“…20 for only a narrow range of the hydrogen storage capacity F. This has also been reported by Reilly et al (1989) and can probably be attributed to the fact that at higher temperatures, the equilibrium between the a and @ phase exists in a narrow region for F. It appeared that the observed rate constant k i increases when the difference between the equilibrium desorption pressure and the reactor pressure becomes larger. According to Flanagan (1978) and Reilly et al (1989) the driving force for this phase boundary controlled process is ln(Peq,d/PH2). The rate constant k& has been divided by ln(PeQqd/PHJ in order to obtain the kd.…”

“…Subsequently, the precise mechanism can be obtained by plotting some selected rate equations (based on the value of q) over a wider range for X . According to Reilly et al (1989), hydrogen bubbles are formed on the metal surface during hydrogen desorption from a hydride slurry. The metal hydride is then in equilibrium with the gas phase and concentration gradients in the liquid phase are absent during desorption, as shown in Figure 1 .…”

“…The desorption experiments have been carried out according to the procedure as presented by Reilly et al (1989). First the hydride slurry was saturated at 0.5 to 1 bar above the absorption equilibrium pressure.…”

Absorption of Hydrogen in LaNi4.75Al0.25/n-Octane Slurries

“…Reilly and Johnson, 1988 Summarized metal hydride slury systems. Reilly et al, 1989 The isothermal kinetics of the desorption of the hydrogen ( f R phase) from LaNi 5Hx were investigated for both n-undecane and n-octane systems.…”