The rare earth doped Mg2Ni (0 1 0) surface enhances hydrogen storage

Abstract

Rare earth doping has been proved to be an effective method to improve hydrogen storage properties of Mg-based alloys. In this work, the effect of rare earth (Y, Ce, La, Sc) doping on the thermal stability, electronic property and hydrogen adsorption/desorption behavior of Mg2Ni (010) surface are systematically investigated by first principles calculation. The results show that rare earth doping in Mg2Ni (010) surface are thermodynamic feasible. The calculated electronic structures shown that rare earth atoms weaken the binding strength between H and Mg2Ni (010) substrate, thus reduce the hydrogen diffusion and desorption energies barriers, and improve the hydrogen storage properties of Mg2Ni. Among the four rare earth elements, Ce shows the best potential. Notably, the substitution doping of Ce to Mg atom significantly reduces the H diffusion barrier by 0.32 eV and H2 desorption barrier by 1.0 eV. This discovery provides a direction for the preparation of rare earth doped Mg2Ni hydrogen storage materials.