Effect of Elemental Doping on the Adsorption Behavior and the Mechanism of Hydrogen Adsorption on the Zirconium Surface

This study used the Monte Carlo (MC) and density functional theory (DFT) methods to simulate the adsorption process of a H atom on element (vacancy, Cr, Sn, and Fe)-doped Zr(0001) surfaces and further analyzed the adsorption site distribution, adsorption energy, charge transfer, and electronic structure, etc. of the doped zirconium surface model. Simulated results indicated that (i) although the doping of vacancy, Cr, Sn, and Fe had a significant effect on the adsorption site distributions of the H atom on the Zr(0001) surface, they showed completely different distribution patterns. (ii) Vacancy doping promoted the adsorption of the H atom on the Zr(0001) surface. The H atom would penetrate the zirconium matrix along the vacancy and then occupy the octahedral gap stably. On the contrary, the doping of Cr, Sn, and Fe inhibited Zr(0001) surface hydrogen uptake in the order of Fe > Cr > Sn, where the effect of Sn could be negligible. (iii) Fe doping had the greatest effect on the chemical reaction mechanism of H adsorption on the Zr(0001) surface, which significantly converted the chemical reaction from Zr-H- to Fe-H-dominated, while Cr doping caused the formation of the Cr-H and Zr-H coaction mechanism, and Sn doping had almost no effect on the mechanism of H adsorption on the Zr(0001) surface.