First-principles study on the hydrogen storage properties of MgH2(1 0 1) surface by CuNi co-doping

• Pure, Cu doped, Ni doped and CuNi co-doped MgH 2 (101) are studied by DFT method. • The MgH 2 (101) systems after doping metal (Cu or/and Ni) atoms are stable. • The surface of CuNi co-doped MgH 2 (101) exhibits obvious hydrogen adsorption capacity. • Temperature can strongly control hydrogen desorption in CuNi co-doped system. 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 (101) surface. The most stable energy adsorption site for hydrogen on the surface of CuNi co-doped MgH 2 (101) 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 (101) surface of CuNi co-doped MgH 2 can be well matched with itself to obtain the additional hydrogen storage region.