Influence of Hf Doping on the Oxygen Behaviors on ZrCo(110) Surface Using First-Principles Calculation.

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Zirconium-Cobalt (ZrCo) alloys are susceptible to poisoning by impurity gases like oxygen, degrading hydrogen storage capabilities.
• Hafnium (Hf) substitution can enhance ZrCo alloy's anti-disproportionation properties, but its effect on anti-poisoning remains uninvestigated.

Purpose of the Study:

• To investigate the adsorption, dissociation, and diffusion of oxygen on the ZrCo(110) surface.
• To examine the impact of Hafnium (Hf) doping on these oxygen interaction characteristics.
• To determine the viability of Hf doping as a strategy to improve ZrCo alloy's resistance to oxygen poisoning.

Main Methods:

• First-principles calculations were employed to simulate and analyze oxygen interactions on the ZrCo(110) surface.
• The study focused on adsorption sites, dissociation pathways, and diffusion barriers for oxygen atoms.

Main Results:

• Oxygen molecules readily dissociate and adsorb stably at hollow sites on the pure ZrCo(110) surface.
• Oxygen atoms preferentially occupy surface sites before diffusing inwards.
• Hf doping showed minimal effect on oxygen adsorption and dissociation but reduced the surface-to-subsurface diffusion barrier by 0.61 eV.

Conclusions:

• Hf doping enhances oxygen permeability into the ZrCo(110) subsurface.
• This increased oxygen diffusion suggests that Hf doping is not a suitable strategy for improving the alloy's resistance to oxygen poisoning.
• Further research may explore alternative doping elements or surface modifications to enhance anti-poisoning properties.