Influence of the Fe-doping on hydrogen behavior on the ZrCo surface. (1st October 2021)

• Record Type: Journal Article
• Authors: Wang, Qingqing; Kong, Xianggang; Yu, You; Song, Jiangfeng; Wu, Lu
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 68(2021)
• Page Start: 33877
• Page End: 33888
• Publication Date: 2021-10-01
• Subjects: First principles -- ZrCo -- Hydrogen storage -- Surface adsorption; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.07.198
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Ab initio calculations have been carried out to investigate the adsorption, dissociation, and diffusion of atomic and molecular hydrogen on the Fe-doped ZrCo (110) surface. It is found that the adsorption of H2 on doped surface seems thermodynamically more stable with more negative adsorption energy than that on the pure surface, and the dissociation energy of H2 on doped surface is much bigger therefore. However, compared with the pure system, there are fewer adsorption sites for spontaneous dissociation. After dissociation, the higher hydrogen adsorption strength sites would promote the H atom diffusion towards them where they can permeate into the bulk further. Furthermore, the ZrCo (110) surface possesses much higher hydrogen permeability and lower hydrogen diffusivity than its corresponding ZrCo bulk. Moreover, further comparison of the present results to analogous calculations for pure surface reveals that the Fe dopant facilitates the H2 molecule dissociation. Unfortunately, this does not improve the hydrogen storage performance of ZrCo alloy due to the H atom diffusion on the surface and into bulk are prevented with higher reaction energetic barriers by doping Fe. Consequently, ZrCo (110) surface modified with Fe atoms should not be preferred as a result of its terrible hydrogen permeability. A clear and deep comprehending of the inhibiting effect of Fe dopant on the hydrogen storage of ZrCo materials from the perspective of the surface adsorption of hydrogen are obtained from the present results. Highlights: H2 adsorption energies decrease due to the Fe atom decorating. The number of the sites for H2 spontaneous dissociation on is fewer. The number of the stable adsorption sites of the single H2 molecules is fewer. The diffusion and permeation into the subsurface of H atom are suppressed. The Fe doping is adverse to improving hydrogen storage performance of ZrCo alloy.