The structures of sulphur on Pd(111) studied by X-ray standing wavefield absorption and surface EXAFS

Adsorption and dissociation of H2S on Mo2C(001) surface-A first-principle study

“…The adsorption energy of sulfur atom on Mo 2 C(001) surface is weaker than that on Mo(100) of 185.85 kcal/mol, while much stronger than that on Fe(100) of 66.74 kcal/mol [14]. These results are also consistent with the experiment observations that S atoms remain on the surface even for the temperatures in excess of 800 K [55][56][57]. The binding energy between S and Mo 2 C(001) surface is much stronger than that SH/Mo 2 C(001) and H 2 S/Mo 2 C(001) (77.20 kcal/mol, 26.12 kcal/mol, respectively) at their most stable adsorption sites, indicating that the thermodymic driving force is large for H 2 S dissociation on Mo 2 C(001) surface.…”

“…Sulfuhydryl (SH): There are a number of experimental studies of H 2 S decomposition on sulfided Pd(111) [56][57][58], and Mo(100) [7,8]. It was found that at room temperature, H 2 S dissociates quickly on Pd(111) surface giving rise to absorbed S species [59].…”

Ab initiostudies of stepped Pd surfaces with and without S

“…51,52 The search of such structures would require addressing much lower coverages than in the present work, which using the method at hand would need prohibitively large supercells. Nevertheless, the fact that the S atoms prefer positions close to the steps suggests the possible formation of S stripes along the step edges.…”

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

“…Thus, the study of the structure of the adsorbed S is of crucial importance. The key model system, S adsorption on the Pd(1 1 1) surface, has been the subject of numerous experimental studies [13,[18][19][20][21][22][23][24][25][26][27]. The picture arising from these investigations is that the behavior of S on the surface is quite varied and depends markedly on the coverage and temperature.…”

“…Additionally, few areas of S islands with local ( p 7 · p 7) and (2 · 2) structures were also identified [26,27]. LEED analysis and normal incidence X-ray standing wave (NIXSW) measurements show that S atoms in the ( p 3 · p 3) structure occupy threefold fcc hollow sites [22,23,25]. At elevated temperatures (400-700 K), a predominantly ( p 7 · p 7) pattern emerges [20,26,27].…”