First-principles study of the structure of water layers on flat and stepped Pb electrodes

Abstract

SummaryOn the basis of perodic density functional theory (DFT) calculations, we have addressed the geometric structures and electronic properties of water layers on flat and stepped Pb surfaces. In contrast to late d-band metals, on Pb(111) the energy minimum structure does not correspond to an ice-like hexagonal arrangement at a coverage of 2/3, but rather to a distorted structure at a coverage of 1 due to the larger lattice constant of Pb. At stepped Pb surfaces, the water layers are pinned at the step edge and form a complex network consisting of rectangles, pentagons and hexagons. The thermal stability of the water layers has been studied by using ab initio molecular dynamics simulations (AIMD) at a temperature of 140 K. Whereas the water layer on Pb(111) is already unstable at this temperature, the water layers on Pb(100), Pb(311), Pb(511) and Pb(711) exhibit a higher stability because of stronger water–water interactions. The vibrational spectra of the water layers at the stepped surfaces show a characteristic splitting into three modes in the O–H stretch region.

Surface configuration and wettability of nickel(oxy)hydroxides: a first-principles investigation

“…Ab initio molecular dynamics (AIMD) simulations were performed to account for thermal fluctuations in ordering of surficial water at Ni (oxy)hydroxides (001). This computational study expands the scope of similar studies on water/transition metal interfaces [29,39,40,41,42,43,44,45] towards water/oxides surfaces.…”

“…Among various examined orientations shown in Table 1, it was found that on β-NiOOH 25/75 (001) a water monomer binds via its oxygen atom to OH ad with d H2O-OH = 2.70 Å, as can be seen in In order to separate water-NiO x from water-water interactions, we performed an energy calculation for an isolated hexagonal water layer with all water molecules fixed in positions as in the configuration of the water layer when adsorbed on β-Ni(OH) 2 (001) or β-NiOOH 75/25 (001). The strength of water-water interactions can be calculated as [41],…”

Water adsorption on bimetallic PtRu/Pt(111) surface alloys

“…Single water molecules adsorb on close-packed metal surfaces typically through their oxygen atom at a top position in a flat configuration with the hydrogen atoms almost at the same height as the oxygen atom [17,44]. This is also the case for isolated water molecules at a coverage of 1 3 adsorbed on PtRu/Pt(111) surface alloys, as illustrated for a Pt 2 Ru 1 /Pt(111) surface alloy in figure 1.…”

Studi Dinamika Molekular dan Kinetika Reaksi pada Pembelahan Molekul Air untuk Produksi Gas Hidrogen

“…Pemodelan dari aspek interaksi antara permukaan elektroda dan sisi dinamika molecular molekul H2O yang bertabrakan atau bersentuhan dengan permukaan elektroda sehingga proses splitting bisa dijelaskan. Permukaan elektroda menjadi kajian yang menarik diteliti seperti dilaporkan Xu et al (2017) tentang factor roughness pada permukaan padatan berpori terhadap evolusi gas yang dihasilkan (11)(12)(13)(14). Dalam paper ini ditelaah kemungkinan pola interaksi molecular H2O dan permukaan padatan elektroda melalui pemodelan.…”