Comparison of S Poisoning Effects on CO Adsorption on Pd, Au, and Bimetallic PdAu (111) Surfaces

S and CO adsorption and coadsorption on Pd(111), Au(111), and PdAu(111) surfaces Were Studied, with the aim of providing insight into the poisoning effects of S and searching for novel sulfur-tolerant catalyst materials by first-principles Calculations. It was found that both neighboring and next-nearest-neighboring adsorption sites are poisoned by a single preadsorbed S atom for CO adsorption on Pd(111). On Au(111), E-ad of CO increases because of preadsorbed S, indicating that preadsorbed sulfur does not always act as a poison. The bimetallic PdAu(111) surface was found to have better S poison resistance than the Pd(111) and better activity than the Au(111) monometallic surfaces for CO adsorption. Meanwhile, the CO stretching frequencies oil each surface with and Without S were calculated to depict the effects of S preadsorption oil the C-O bond strength.