Water confined at the nanoscale has been focus of numerous experimental and theoretical investigations in recent years, yet there is no consensus on such basic properties as diffusion nature hydrogen bonding (HB) under confinement. Unraveling these important to understand fluid flow transport nanoscale, shed light solvation biomolecules. Here we report a first principle, computational study focusing water between prototypical nonpolar substrates, i.e., single-wall carbon nanotubes graphene...

Although generally ascribed to the presence of defects, an ultimate assignment different contributions emission spectrum in terms surface states and deep levels ZnO nanostructures is still lacking. In this work we unambiguously give first evidence that zinc vacancies at (1010) nonpolar surfaces are responsible for green luminescence nanostructures. The result obtained by performing exhaustive comparison between spatially resolved cathodoluminescence spectroscopy imaging ab initio...

The development of efficient CO

In this work, ZnO thin films were investigated to sense NO2, a gas exhausted by the most common combustion systems polluting environment. To end, grown RF sputtering on properly designed and patterned substrates allow measurement of electrical response material when exposed different concentrations gas. X-ray diffraction was carried out correlate material's morphological microstructural features sensing materials. Electrical conductivity measurements showed that transducer fabricated in work...

The interaction of water with Si- and C- terminated $\ensuremath{\beta}\mathrm{\text{\ensuremath{-}}}\mathrm{S}\mathrm{i}\mathrm{C}(001)$ surfaces was investigated by means ab initio molecular dynamics simulations. Irrespective coverage, varied from $1/4$ to 1 monolayer, we found that dissociates on the Si-terminated surface, substantially modifying clean surface reconstruction, while C-terminated is nonreactive hydrophobic. Based our results, propose STM images photoemission experiments may...

Two-dimensional MoS2 is a promising material for nanoelectronics and catalysis, but its potential not fully exploited since proper control of multiple phases (H, T, ZT) electronic properties lacking. In this theoretical study, alloying proposed as method to stabilize the T-phase. particular, alloyed with another that known exist in monolayer MX2 T-structure, we show formation energy difference among decreases even low impurity concentrations MoS2, relationship between concentration alloy...

Desalination and water purification are among the most promising approaches to supply clean in context of a rapidly growing global shortage. Reverse osmosis (RO) is common approach that utilizes pressure-driven solvent diffusion across semi-permeable membrane remove small ions or molecules from feed-stream. Traditional polymeric RO membranes, e.g., based on polyamide as active layer, inexpensive have been shown perform well for variety salts effluents; however, these materials also number...

In this work, we report on the exciton radiative lifetimes of graphitic carbon nitride monolayers in triazine- (gC$_3$N$_4$-t) and heptazine-based (gC$_3$N$_4$-h) forms, as obtained by means ground- plus excited-state ab initio calculations. By analysing fine structure, highlight presence dark states show that photo-generated electron-hole pairs gC$_3$N$_4$-h are remarkably long-lived, with an effective lifetime 260 ns. This fosters employment photocatalysis makes it attractive for emerging...

Tin monoxide (SnO) undergoes a phase transition from litharge-like tetragonal (space group P4/nmm) to orthorhombic geometry (layer pmmn) in passing multilayer monolayer crystals. By means of ab initio ground and excited-state methods, we explore the impact reduced pmmn spatial symmetry on electronic optical properties SnO monolayers. As consequence in-plane anisotropy, states band edges show asymmetric projections onto px py atomic orbitals along orthogonal directions Brillouin zone. This...

We compare calculations of infrared (IR) spectra water confined between nonpolar surfaces, obtained by molecular dynamics simulations with forces either computed using density functional theory or modeled empirical potentials. Our study allows for the identification important electronic effects, contributing to IR signals, that are not included in based on force fields, and cannot be extracted from analysis vibrational states. These effects originate charge fluctuations involving both...

In this paper we present a microscopic picture of the interface between liquid water and Au(111) surface at room temperature conditions, as obtained from ab initio molecular dynamics simulations. We find that first wetting layer has peculiar structural electronic features can be revealed only by considering dynamical evolution system. Surface phonons vibrations lead to instantaneous charge density distortions are pivotal explain such an atypical layer, and, in turn, hydrophilicity.

Proteins able to recognize inorganic surfaces are of paramount importance for living organisms. Mimicking nature, surface-recognizing proteins and peptides have also been man-made by combinatorial biochemistry. However, date the recognition mechanisms remain elusive, underlying physicochemical principles still unknown. Selectivity gold-binding (cysteine-free rich in hydroxyl amino acids) is particularly puzzling, since most relevant gold surface, Au(111), known be chemically inert atomically...

Resistive switching memory operation is generally described in terms of formation and rupture a conductive filament connecting two metal electrodes. Although this model was reported for several device types, its applicability not guaranteed to all them. On the basis density functional theory calculations, we propose novel mechanism suitable nanowire-based resistive memories. For thick devices particular, current highly unlikely flow through metallic We demonstrate that case ZnO nanowires...

A ZnO nanowires memristor switching between multiple resistance states. The conductivity of is tuned by changes in surface states that are induced at ZnO/polymer interfaces redox reactions guided an external bias.

Abstract Nitrogen-doped reduced graphene oxide is successfully synthesized and functionalized with hydroxylated copper ions via one-pot microwave-assisted route. The presence of cationic Cu coordinated to the layer fully elucidated through a set experimental characterizations theoretical calculations. Thanks these hydroxyl-coordinated 2+ active sites, proposed material shows good electrocatalytic performance for oxygen reduction reaction, as evidenced by an electron transfer number almost 4...

Tin oxide (SnO2) is an efficient catalyst for the CO2 reduction reaction (CO2RR) to formic acid; however, understanding of SnO2 surface structure under working electrocatalytic conditions and nature catalytically active sites a current matter debate. Here, we employ ab initio density functional theory calculations investigate how selectivity reactivity surfaces toward CO2RR change at varying stoichiometry (i.e., degree). Our results show that SnO2(110) are not or hydrogen evolution reaction,...

We present a microscopic model of the interface between liquid water and hydrophilic, solid surface, as obtained from ab initio molecular dynamics simulations. In particular, we focused on (100) surface cubic SiC, leading semiconductor candidate for biocompatible devices. Our results show that in contact with clean substrate, dissociation occurs manner unexpectedly similar to observed gas phase. After full hydroxylation takes place, formation thin (∼3 Å) interfacial layer is observed, which...

Solid-state nanostructured gas sensors based on oxide materials play an important role in environmental monitoring, chemical process control, and personal safety. Yet, the underlying operating mechanism is still not well comprehended, while a deeper understanding would possibly lead to engineering of sensing elements with enhanced sensitivities. Here we present ab initio density functional theory calculations that provide comprehensive description ethanol for ZnO nanowires: our results...

Graphene oxide (GO) is a versatile 2D material whose properties can be tuned by changing the type and concentration of oxygen-containing functional groups attached to its surface. However, detailed knowledge dependence chemo/physical features this on chemical composition largely unknown. We combine classical molecular dynamics density theory simulations predict structural electronic GO at low degree oxidation suggest revision Lerf-Klinowski model. find that layer deformation larger for...