Adsorption of arsenic trihydride ([formula omitted]) on palladium oxide (PdO) surface (001): ab initio study

Abstract

Adsorption and decomposition thermochemistry of AsH3 on the surface (001) of PdO(PdO–O and PdO–Pd) were performed using the Density Functional Theory (GGA-PBE and vdW-DF2-C09). The bridge-oy (B2) site is the most energetically stable with an adsorption energy of 2.834 eV for the work performed with the GGA-PBE functional, while the bridge-ox (B1) site is the most energetically stable with an energy of 2.394 eV with the vdW-DF2-C09 functional for the PdO–O surface. The adsorbate undergoes chemisorption on the PdO(001) surface, the coverage rate has an influence on the adsorption energy. The results of the isosurfaces and LDOS show, on one hand, for the PdO–O surface, a phenomenon of charge transfer from the molecule to the surface in the case of an As–O bond formation; and on the other hand, for the PdO–Pd surface, a charge distribution. The thermochemistry of AsH3 is very favourable on the PdO surface with the GGA-PBE functional group, then with the vdW-DF2-C09 functional group the first two reaction paths of the PdO–O surface are very favourable, while the last reaction path is unfavourable to total decomposition; similarly on the PdO–Pd surface with the vdW-DF2-C09 functional group the thermochemistry of the first reaction path is unfavourable, while the last two reaction paths are favourable.