Water adlayers on noble metal surfaces: Insights from energy decomposition analysis

Abstract

Water molecules adsorbed on noble metal surfaces are of fundamental interest in surface science, heterogeneous catalysis and as a model for the metal/water interface. Herein, we analyse 27 water structures adsorbed on five noble metal surfaces (Cu, Ag, Au, Pd, Pt) via density functional theory and energy decomposition analysis based on the block localized wave function technique. The structures, ranging from the monomers to ice adlayers, reveal that the charge-transfer from water to the surface is nearly independent from the charge-transfer between the water molecules, while the polarization energies are cooperative. Dense water-water networks with small surface dipoles, such as the sqrt(39) x sqrt(39) unit cell (experimentally observed on Pt(111)) are favored compared to the highly ordered and popular H up and H down phases. The second main result of our study is that the many-body interactions, which stabilize the water assemblies on the metal surfaces, are dominated by the polarization energies, with the charge-transfer scaling with the polarization energies. Hence, if an empirical model could be found that reproduces the polarization energies, the charge-transfer could be predicted as well, opening exciting perspectives for force field development. File list (3) download file view on ChemRxiv WaterLayers_Main.pdf (749.93 KiB) download file view on ChemRxiv WaterLayers_SI.pdf (282.38 KiB) download file view on ChemRxiv imecs.tar.gz (14.15 KiB) Water Layers On Noble Metals

Highly Heterogeneous Polarization and Solvation of Gold Nanoparticles in Aqueous Electrolytes

“…For the design of improved polarizable force fields, one could benchmark classical approaches to ab initio MD (AIMD) approaches and compare water oxygen and hydrogen profiles as well as the total charge contribution across the interface. − AIMD studies suggest, for instance, that the interface dipole has significant contributions from partial charge transfer from the water layer to the metal, given that there is no preferential orientation of the solvating water molecules in metal–water interfaces . Effects of charge transfer at the gold–water interface are smaller than at other metal surfaces, but a complete quantitative understanding (including the presence of ions) is still not achieved. Therefore, a consistent convergence of AIMD and classical polarizable models in that matter is highly desirable.…”

Ab Initio Simulations of Water/Metal Interfaces

“…For example, on Pt(111), they differ only by 0.03 eV per water molecule . Still, there is one property that differs very strongly between these two orientations of the water bilayer, namely, the work function change of the metal surface upon depositing the icelike bilayers. , On Pt(111), the H-up layer lowers the work function by ΔΦ = −2.34 eV, whereas the H-down only lowers it by ΔΦ = −0.22 eV . Note that the electrode potential of an electrochemical cell can be related to the work function of the water-covered metal surface .…”

“…Unfortunately, the modeling of liquid water requires taking the statistical nature of liquids into account through, e.g., appropriate averaging along sufficiently long molecular dynamics trajectories. In spite of the ever-increasing computer power and the development of more efficient first-principles codes, ab initio molecular dynamics (AIMD) simulations are still computationally rather demanding. − Still, computationally less expensive methods typically cannot faithfully capture important aspects of the water–metal interaction such as, e.g., the strong polarization effects occurring at these interfaces. − Hence, ab initio simulations are compulsory for a true fundamental understanding of the scientifically interesting and technologically important structures and processes at water/metal interfaces. ,, At the same time, they are essential to benchmark more approximate but numerically less demanding theoretical approaches. , …”

In-depth theoretical understanding of the chemical interaction of aromatic compounds with a gold nanoparticle

“…Note that this setup closely follows a previous publication, where it has been shown to yield analogous results to plane-wave basis set computations using VASP. 56 SAPT, on the other hand, treats the interaction energy as the perturbation introduced to the Hamiltonian of the isolated monomer, as it interacts in a dimer. The simplest SAPT method, is SAPT0, whose interaction energy can be defined as: (1) elec + E (1) exch + E (2) ind + E (2) disp (3) This interaction can be decomposed into meaningful physical components, which are electrostatic (E elec ), exchange (E exch ), induction (E ind ) and dispersion (E disp ).…”