Adsorption and diffusion behavior of hydrogen on the M-doped (M=Zr, Mo, Y, Cu, Pd, Ir, Mg, Al, Si) Ti(0001) surfaces: A first-principles study

The adsorption and diffusion behaviors of hydrogen on M-doped Ti(0001) surfaces are investigated by firstprinciples calculations. The surface energies of M-doped surfaces follow the ordering of Mo > Ti > Zr > Cu > Mg > Y > Al > Pd > Ir > Si. In all the M-doped systems, H atom adsorbed at the next nearest neighboring site is more stable than the nearest neighboring site. All involved M dopants prevent the H adsorption at the nearest neighboring site, and the Si dopant has a significant repulsive effect on it. Both the surface stability and H adsorption behavior are interpreted successfully by the doping effects of s-d hybridization (Al, Si), D-band contribution (Pd, Cu, Ir), and the relative electronegativity (Mo, Zr, Y, Mg). H prefers to penetrate from the surface hcp site to the subtet site and finally to the suboct site, except for the Mo-doped and clean Ti surfaces with the path from the surface fcc site directly to the suboct site. Among these dopants, Mo promotes the H in-plane surface diffusion and Pd promotes the H penetration process most significantly.

Automated summary

The adsorption and diffusion behaviors of hydrogen on M-doped Ti(0001) surfaces were studied using first-principles calculations. The results show that different M dopants affect the surface energy and the adsorption position of hydrogen, as well as the diffusion path of hydrogen on the surface. These findings are important for understanding the effect of M doping on the surface properties of Ti and the behavior of hydrogen on Ti surfaces.