Micro-mechanism study on the effect of O2 poisoned ZrCo surface on hydrogen absorption performance.

Hydrogen storage alloys are usually susceptible to poisoning by O 2 , CO, CO 2 , etc., which decreases the hydrogen storage property sharply. In this paper, the adsorption characteristics of oxygen on the ZrCo(110) surface were investigated, and the effect of oxygen occupying an active site on the surface on the hydrogen adsorption behavior was discussed. The results show that the dissociation barrier of H 2 is increased by more than 26% after O occupies the active sites on the ZrCo(110) surface, and the probability of H 2 adsorption and dissociation decreases significantly. The adsorption energy of H atoms on the O–ZrCo(110) surface decreased by 18–56%, and the adsorption stability of H decreased. In addition, H atom diffusion on the surface and into bulk are prevented with higher reaction energetic barriers by O occupying active sites. Eventually, the ability of the ZrCo surface to adsorb hydrogen is seriously reduced. [Display omitted] • Oxygen molecules are easily adsorbed and dissociated on the ZrCo surface. • The O atoms stably occupy active sites on the ZrCo surface. • The O atoms reduce the adsorption and dissociation ability of H 2 on ZrCo surface. • The O atoms hinder that diffusion and inward penetration of H on ZrCo surface. [ABSTRACT FROM AUTHOR]