Hydrogen absorption of LaNi5 powders precovered with O2, CO, H2S, CO2 or N2

Passivation and reactivation of Ti25V35Cr40 hydrides by cycling with impure hydrogen gas

“…The decline of its baseline at above 300 C might be a result of the accumulation of all gas species. Although the concentration of H 2 S was relatively low, its effect on passivation of the alloy should not be overlooked because it is one of the strongest poisons for LaNi 5 eH, TiFeeH, and other metal catalyst systems [11,12,31]. Therefore, the decomposition of the b-hydride in the as-cycled specimen was apparently inhibited by the presence of H 2 S, O 2 , CO, and CH 4 impurities below 170 C.…”

“…For example, Sakaguchi et al found that hydrogen present in LaNi 5 particles was confined by a monolayer of CO molecules chemisorbed across the particle surface [10]. The catalytic Ni site in the poisoned LaNi 5 hydride was passivated due to the formation of a nickel [11,12,31].…”

Hydrogen purification methods

“…The correlation between surface coverage of the sample, because of the presence of CO, O 2 , H 2 S, N 2 , and CO 2 , and the reaction rate reduction was analyzed by Schweppe, Martin, and Fromm (1997). They first exposed the samples to the gases and then the hydrogen adsorption rate was measured with pure hydrogen.…”

Cycling performance for storage and purification of lanthanum‐rich mischmetal alloy in the presence of hydrogen sulfide

“…26 F. Schweppe et al describe the absorption kinetics of various impurities on the HSA, and the results show that H 2 S and CO have similar poisoning phenomena with the 1 ppm impurity concentration. 27 Cristina et al show that 50 ppm H2S has a nonnegligible effect on the HSA containing Lanthanum element. 28 Research on the impact of H2S on the HSA is still in the exploratory stage.…”