Coadsorption of H and Li on perfect and defective Ag(110) and Ag(111) surfaces: A DFT study with and without dispersion correction

Abstract

Adsorptions of H and Li, and the coadsorption of H and Li on perfect and defective Ag(110) and Ag(111) surfaces have been investigated using pure DFT+PBE and dispersion correction DFT+PBE+d3 calculations. Adsorption energies, coadsorption energies, structural parameters, work function change, dipole moments and projected density of states (PDOS) were calculated in order to elucidate preferential adsorption sites of hydrogen and lithium on each surface. Hydrogen diffusion on perfect Ag(110) and Ag(111) surfaces was studied in objective to obtain diffusion barrier. Our calculations showed that the adsorptions of H and Li as well as the coadsorption of H and Li are favourable on surfaces studied. The PDOS calculations showed a shift in the energy levels, the decrease or increase in the density of states peaks of Li, H and Ag atoms. We found a decrease or increase in the work function change when Li and H are coadsorbed on the Ag(110) and Ag(111) surfaces. Also, the change in the work function after Li–H coadsorption induces a surface dipole moment.