Hydriding/dehydriding kinetics

A. Karty, J. Grunzweig-Genossar, P.S. Rudman, Hydriding and dehydriding kinetics of Mg/ MgjCu eutectic alloy Pressure sweep method, J. Appl. Phys. 50 (1979) 7200-7209. 

A. Yonkeu, I.P. Swainson, J. Dufour, J. Huot, Kinetic investigation of the catalytic effect of a body centered cubic-aUoy TiV, Mn, (BCC) on hydriding/dehydriding properties of magnesium, J. Alloys Compd. 460 (2008) 559-564. 

Another effect is that confinement in pores might influence the phases formed for complex systems. Although not completely understood this is found experimentally, for instance, by Autrey ef al. for the confinement of ammonia borane in mesoporous Si02 and carbon (see Section 10.6.1) [74]. For complex materials often not only thermodynamic considerations but also kinetics have an import influence on which phases are formed upon hydriding or dehydriding. For instance, on decomposition of UBH4 the thermodynamically most favorable reaction is ... 

Determine the kinetics and mechanism of the fundamental dehydriding and rehydriding reactions occurring in the doped hydride. 

Figures 2 and 3, were found to corroborate the data in the literature. The dehydriding proceeds via a two-step mechanism and, without a catalyst, is not reversible. The TVA data, in addition to illustrating the kinetics of the hydride, allowed the calculation of the weight percent of hydrogen released from the material. The TVA data for the sodium aluminum hydride and the lithium aluminum hydride showed obvious release temperatures, while the corresponding borohydrides did not. It was also determined that the TVA and the DSC are complimentary techniques, providing data that match literature values while operating on significantly different sample sizes and theoretical principles.

Rapid absorption and desorption is clearly desirable from an application s point of view. Intrinsic isothermal rates of hydriding and dehydriding are not easy to determine experimentally. In the case of rapid reactions, heat transfer becomes a difficult variable to control and the surface structure is always a problem. It is a fortunate circumstance that the reaction kinetics of most... 

C. Langhammer, V.P. Zhdanov, L Ztnic, B. Kasemo, Size-dependent kinetics of hydriding and dehydriding of Pd nanoparticles. Phys. Rev. Lett. 104(13), 135502 (2010)... 

---