Computational study of the adsorption of molecular hydrogen on PdAg, PdAu, PtAg, and PtAu dimers

Abstract

The adsorption and dissociation of the H 2 molecule on the PdAg, PdAu, PtAg, and PtAu heteronuclear dimers, both isolated and deposited on carbon, were investigated by means of density functional theory. It was found that the Pd and Pt ends of the isolated dimers adsorb H 2 more exoenergetically than the Ag and Au ends. The dimers were also deposited on a carbon support and it turned out that they prefer to adsorb on the support by their Pd and Pt ends rather than by the Ag and Au ends. The adsorption of H 2 on the carbon-supported dimers is somewhat less exoenergetic than that on the isolated dimers but, after the dissociation of H 2 , the binding of the H atoms to the dimers remains stronger in the presence of the support.

Density Functional Study of Molecular Hydrogen Adsorption on Small Gold–Copper Binary Clusters

“…The theoretical studies of the adsorption and reaction of H 2 on bimetallic clusters have also appeared [16][17][18][19][20]. The V site is the favored one for the adsorptions of Al n V (n = 1-13) clusters for a H 2 molecule [16].…”

Theoretical study of the interaction of simple molecules such as H2, C2H2, and C2H4 with Pd–Pb catalysts

“…First, the exoenergetic interaction in the H 2 -PdPb minimum suggests that the H 2 adsorption by the Pd end is energetically preferred. As a matter of fact, the energetic preference of the Pd end has also been observed for the interaction between the H 2 molecule and the PdCu, PdAg, and PdAu bimetallic dimers [51,64]. It obviously results from the fact that Pd exhibits higher activity toward H 2 than the second metals in these dimers.…”

“…It suggests that Pb poisons the H 2 adsorption ability of Pd and, therefore, reduces the catalytic activity of the PdPb dimer. The negative effect produced by Pb seems to be even stronger than that of Cu, Ag, and Au [51,64]. The existence of the barriers at the Pd and Pb ends, i.e., the TS1 and TS3, respectively, excludes spontaneous dissociation of H 2 , while the H 2 dissociation on Pd 2 can proceed without activation energy [65].…”

H2 INTERACTION WITH BIMETALLIC DIMERS SUPPORTED ON THE MgO(100) SURFACE: A DFT CLUSTER MODEL STUDY

“…Before undertaking the investigation of this interaction, we are going to analyze two issues. First, this work is the continuation of our previous study 30 devoted to the interaction between H 2 and the above-mentioned dimers, both isolated and deposited on carbon. For the sake of consistency, we apply here the same computational method, namely Becke's \half-and-half" (BH&H) hybrid density functional, as in Ref.…”

“…For the sake of consistency, we apply here the same computational method, namely Becke's \half-and-half" (BH&H) hybrid density functional, as in Ref. 30. With this in mind, we start with carrying out some test calculations for the adsorption of the Pd, Pt, Ag and Au atoms on MgO (100).…”