First-principles study on the hydrogen storage properties of MgH 2 (1 0 1) surface by CuNi co-doping

Exploring the hydrogen storage properties on the surface of transition metal-modified MgH 2 systems is beneficial to develop new hydrogen storage regions. The first-principles approach was used to study the hydrogen storage mechanism on the CuNi co-doped MgH 2 (1 0 1) surface. The most stable energy adsorption site for hydrogen on the surface of CuNi co-doped MgH 2 (1 0 1) is above the Ni atom, and the corresponding chemisorption energy is −0.51 eV. The distribution of charge densities indicates substantial charge exchange occurs between the hydrogen molecule and Ni atom, while partial density of state analysis reveals orbital hybridization between the H-s (H 2 ) and Ni-d orbits. Furthermore, molecular dynamics simulations indicate that the temperature range (473 to 573 K) of hydrogen desorption on the surface is similar to previous experimental results. Therefore, the (1 0 1) surface of CuNi co-doped MgH 2 can be well matched with itself to obtain the additional hydrogen storage region.