Influence of rare earth doping on hydrogen absorption properties of Zr7V5Fe alloy

Abstract

As a representative of non-evaporative getter, Zr–V–Fe has gained widespread attention due to its advantages including low activation temperatures and rapid hydrogen absorption rates. In this study, we investigated the impact of La and Ce doping on the thermodynamic, kinetic, and activation properties of Zr₇V₅Fe alloy. X-ray diffraction analysis shows that rare earth doping causes a decrease in the cell volume of both the ZrV₂ and α-Zr phases of Zr₇V₅Fe alloy, which results in an increase in the plateau pressure of the alloys. The kinetic curves illustrate that rare earth doping leads to a coarse α-Zr phases and a larger particle size after activation, resulting in a decrease in the hydrogen absorption kinetic properties. As for the activation process, the rare earth doped alloys exhibit excellent activation with shorter incubation periods. X-ray photoelectron spectroscopy investigations reveal that Zr and V are initially in a highly oxidized state. As the heating temperature increases, they undergo a transition from oxidation state to metal state. The content of metal Zr in rare earth doped alloys is higher than that in undoped alloys at 250 °C, primarily due to rare earth elements' affinity for oxygen.