Xe Adsorption on Noble Metal Clusters: A Density Functional Theory Investigation

Abstract

The adsorption mechanism of xenon on three noble metal clusters (M = Ag, Au, and Cu) has been investigated in the framework of density functional theory (DFT) within generalized gradient approximation (GGA-PBE). The ab initio calculations were performed with the quantum molecular dynamics (QMD) package ABINIT using the projector augmented (PAW) formalism. The spin–orbit coupling (SOC) and dispersion effects (Van der Waals DFT-D3) have been taken into account. According to these calculations, the M–Xe bonds are partly covalent and electrostatic and their contribution depends on the cluster size and nature. This study underlines the importance of using the SOC and the Van der Waals (VdW) effects. Based on these results, copper nanoparticles have the highest affinity for interaction with xenon compared with silver and gold.

Investigating the Effects of Ag, Cu, and Pd Functionalized Chabazite on the Adsorption Affinities of Noble Gases Xe, Kr, and Ar

“…A combination of both a chemical and physical control on noble gas binding to metal cation clusters is expressly modeled in Monpezat et al as well. 25 From the evidence gathered here, it is not clear whether the Ag-CHA system could reach a limiting capacity for Xe affinity as a function of higher Ag functionalization as only one concentration of functionalized Ag-CHA was prepared. It is possible that a fully exchanged Ag-CHA may prove less efficient or have a lower capacity to adsorb Xe if the higher exchange results in significant pore blockage.…”

“…Taking both forms of evidence into account leads to the conclusion that there is both a physical and electronic component unique to the Ag-CHA system controlling its affinity for Xe. A combination of both a chemical and physical control on noble gas binding to metal cation clusters is expressly modeled in Monpezat et al as well . From the evidence gathered here, it is not clear whether the Ag-CHA system could reach a limiting capacity for Xe affinity as a function of higher Ag functionalization as only one concentration of functionalized Ag-CHA was prepared.…”

On the nature of noble gas – metal bond in silver aggregates

“…We neglected the effects of magnetism in our systems, in accordance with previous studies. 32 First, the bare silver cluster is placed in a cubic box and relaxed. The periodic nature of ABINIT requires an essentially empty DFT mesh to effectively isolate the system from its periodic images.…”