Utilizing the Surface Electrostatic Potential to Predict the Interactions of Pt and Ni Nanoparticles with Lewis Acids and Bases - σ-Lumps and σ-Holes Govern the Catalytic Activities

Abstract

An improved understanding of the interactions of transition-metal (TM) nanoparticles with Lewis acids/bases will facilitate the design of more efficient catalysts. Therefore, Pt14, Pt13, Pt12, and Ni12 nanoparticles have been studied at the TPSSh/Def2-TZVP level of density functional theory (DFT). Surface electrostatic potential [VS(r)] maps are used to analyze the Lewis acidic and basic properties of all nanoparticles and indicate that the interactions of Pt and Ni nanoparticles are governed by σd-holes and σs-holes, respectively. Lewis acids (Na+, HF) and a Lewis base (H2O) have been tested as ligands to probe the local interaction proficiencies. The comparison between binding energies and VS(r) shows that the lowest minimum (VS,min) and highest maximum (VS,max) of VS(r) on each particle can predict the most favorable binding site for the Lewis acids and base, respectively. VS,min can also rank the different binding strengths of Na+ and HF with the nanoparticles. For H2O, the binding strength versus VS,max correlation is better for Ni12 than for the Pt nanoparticles. This observation is discussed in relation to charge transfer/polarization and structural deformation upon interaction. In light of our findings, we compare the catalytic potential of Ni to the less abundant but more commonly used Pt.