First-principles study of sulfur overlayers on Pd(111) surface

The effect of H2S on the performance of Pd and Pd/Au composite membrane

“…The possible reason for the variation of the desorption rate of the adsorbed sulfur was that the adsorbed sulfur was bonded to the Pd/Au alloy surface with different binding energies. It has been shown by theoretical calculations that the binding energy of sulfur to Pd decreased as the sulfur coverage was increased (from 5.07 ev/S atom at 0.11 ML to 3.29 ev/S atom at 1 ML) due to the increase of the repulsive force between sulfur atoms with increasing sulfur coverage [42]. As the sulfur coverage decreased during the recovery, the binding energy between sulfur and Pd increased, resulting in the lower desorption and permeance recovery rate.…”

Hydrogen oxidation reaction on Pd(111) electrode in alkaline media: Ab-initio DFT study of OH effects

“…Recent developments in the abinitio density functional theory (DFT) calculations have allowed us to probe the adsorption phenomenon practically on any type of the electrode surface [6,18,19]. Many novel metallic surface properties such as nanoelectrode activity, quantum conductivity, docking molecule's orientation on the electrode surface, and collective behavior of various types of surface adsorbents can also be calculated with a high precision value by the DFT based atomistic simulations [20][21][22]. Besides, the DFT is also competent enough to effectively predict many diverse parameters of the electrolysis; the exact nature and role of the electrode material, role of electrolytic bath, reaction pathways, involved intermediates, etc.…”

Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration

“…According to previous theoretical work [41], the binding energy of sulfur to the FCC sites of the Pd (1 1 1) surface decreased from 5.07 to 3.29 eV/atom at 0.11 and 1.0 ML (monolayers) respectively, meaning that the strength of the bond decreased as the surface coverage increased. A similar trend was seen with the HCP (hexagonal close packed) surface adsorption sites and with the tetragonal and octahedral subsurface adsorption sites as the sulfur coverage increased [41,42]. This phenomenon was also seen with sulfur adsorption on Ni and Pt where the heat of adsorption increased with increasing sulfur coverage.…”

“…Since increasing the amount of sulfur on the surface decreased the bond strength of the adsorbed sulfur [41], it would appear that it was the amount of subsurface adsorbed sulfur which increased with exposure time, thereby increasing the irreversibility of the membrane poisoning. …”