Theoretical insights into acetylene adsorption on nanoporous gold surfaces: Role of residual silver

Abstract Unveiling the acetylene adsorption is crucial for designing novel and highly active catalyst for the semihydrogenation of alkyne. In order to achieve this goal, we have studied C 2 H 2 adsorption on the various nanoporous gold models in detail, including the Au(100), Au(111) and Au(321) slab models. The calculated results indicate that the C atoms of C 2 H 2 experience rehybridization from sp toward sp 2 /sp 3 when the adsorption occurs on bridge and hollow sites, which can be illustrated via the projected density of state (PDOS) and crystal orbital Hamilton population (COHP). Meanwhile, the formation of σ(Au C) bond is beneficial for facilitating acetylene adsorption and the kink Au atom plays an important role for the C 2 H 2 adsorption. In addition, for C 2 H 2 adsorption on the Ag doped nanoporous gold, the configurations strongly depend on the position of superficial unsubstituted Au atoms. Further, the inversely relationship has been found between the adsorption energies and number of the Ag substituents, demonstrating that the superficial Ag substituents are harmful for C 2 H 2 adsorption and activation.