Insights into the hydrogen adsorption and diffusion on α-Fe (110) surface with the Al doping: First-principles study

First-principles calculations were adopted to investigate the adsorption and diffusion of hydrogen on Al-doped α-Fe (110). The main research results show that: (1) Al doping reduces the adsorption stability of hydrogen. Compared with the undoped surface, the adsorption energy of the first layer of doping increases by 1.12 eV, and that of the second layer of doping increases by 0.51 eV. (2) The second layer of doping alters the electronic environment of surface Fe atoms through interfacial electronic recombination, thereby weakening the Fe–H interaction and showing a better inhibitory effect. (3) Bulk Al doping increased the hydrogen diffusion barrier by 3.3 kJ/mol, hindering the infiltration of hydrogen underground. Crucially, the doping of Al at different positions reduces the adsorption stability of hydrogen atoms. These results indicate that adding Al atoms and changing the doping position can enhance the hydrogen brittleness resistance of the material. • Molecular simulation was adapted using first-principles. • Micro-process of hydrogen adsorption and diffusion after Al doping was studied. • The influence of different Al doping points on the hydrogen behavior was revealed. • Influence mechanism of hydrogen behavior inhibition by Al doping was proposed.