Electronic Anisotropy at Vicinal Ag(1 1 n) Surfaces: Energetics of Hydrogen Adsorption

M.F. JUAREZ; E. SANTOS *, K.PÖTTING, P. VÉLEZ, R. R. NAZMUTDINOV

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 120 p. 2109 - 2118

1932-7447

We have investigated the adsorption anddiffusion of hydrogen atoms at planar (1 0 0), (1 1 1), andstepped (1 1 n) silver surfaces by density functional theory. Atlow coverage, hydrogen atoms tend to adsorb on step sitesrather than on the terrace. The adsorption energy forhydrogen on steps stays almost the same for all (1 1 n)surfaces, showing the local character of the orbitals on thesesites. However, the situation is different on the terrace. Theadsorption depends on both the position and the length of theterrace. The stability of hydrogen is higher on the middle ofthe terrace. In contrast to the planar (1 0 0) surface, theadsorption energy decreases when the coverage on the stepsincreases. Small activation barriers for the up- or downward diffusion show that hydrogen atoms can reach the steps easily atroom temperature.