Electronic structure regulation toward the improvement of the hydrogenation properties of TiZrHfMoNb high-entropy alloy

Active metals, such as platinum and palladium, were doped in TiZrHfMoNb high-entropy alloy to tune its electronic structure. The electronic structure, activation, and kinetic properties were experimentally investigated. The results indicate that electron transfer occurred between the active metal atoms and other metal atoms after platinum or palladium doping, and that the oxide on the surface was destabilized by active metal doping due to improved activation performance. Therefore, TiZrHfMoNbPt0.0025 could reach a maximum hydrogen storage capacity of 1.749 wt% (1.80 H/M) at around 100 s on the first absorption curve. The electron transfer process is believed to aid in optimizing the electron density of interstitial sites, allowing additional interstitial sites to accommodate additional hydrogen atoms. The presented results provide new insights into the hydrogen storage properties of high-entropy alloys, and it is expected that hydrogen storage capacity can be increased by tuning the concentration and type of doping elements.