Marco Smerieri | Consiglio Nazionale delle Ricerche (CNR) (original) (raw)

Papers by Marco Smerieri

Toxics

The aim of this study was to investigate the ecotoxicity of polyvinylidene difluoride (PVDF) and ... more The aim of this study was to investigate the ecotoxicity of polyvinylidene difluoride (PVDF) and polylactic acid (PLA) microplastics (MPs) in two marine zooplankton: the crustacean Artemia franciscana and the cnidarian Aurelia sp. (common jellyfish). To achieve this goal, (i) MP uptake, (ii) immobility, and (iii) behavior (swimming speed, pulsation mode) of crustacean larval stages and jellyfish ephyrae exposed to MPs concentrations (1, 10, 100 mg/L) were assessed for 24 h. Using traditional and novel techniques, i.e., epifluorescence microscopy and 3D holotomography (HT), PVDF and PLA MPs were found in the digestive systems of the crustaceans and in the gelatinous tissue of jellyfish. Immobility was not affected in either organism, while a significant behavioral alteration in terms of pulsation mode was found in jellyfish after exposure to both PVDF and PLA MPs. Moreover, PLA MPs exposure in jellyfish induced a toxic effect (EC50: 77.43 mg/L) on the behavioral response. This study ...

Physical Chemistry Chemical Physics

Graphene nanoribbons (GNRs) are at the frontier of research on graphene materials since the 1D qu... more Graphene nanoribbons (GNRs) are at the frontier of research on graphene materials since the 1D quantum confinement of electrons allows for the opening of an energy gap.

Quantum anomalous Hall effect, with a trademark of dissipationless chiral edge states for electro... more Quantum anomalous Hall effect, with a trademark of dissipationless chiral edge states for electronics/spintronics transport applications, can be realized in materials with large spin-orbit coupling and strong intrinsic magnetization. After Haldane's seminal proposal, several models have been presented to control/enhance the spin-orbit coupling and intrinsic magnetic exchange interaction. After brief introduction of Haldane model for spineless fermions, following three fundamental quantum anomalous Hall models are discussed in this perspective review: (i) lowenergy effective four band model for magnetic-doped topological insulator (Bi,Sb)2Te3 thin films, (ii) four band tight-binding model for graphene with magnetic adatoms, and (iii) two (three) band spinfull tight-binding model for ferromagnetic spin-gapless semiconductors with honeycomb (kagome) lattice where ground state is intrinsically ferromagnetic. These models cover two-dimensional Dirac materials hosting spinless, spinful and spin-degenerate Dirac points where various mass terms open a band gap and lead to quantum anomalous Hall effect. With emphasize on the topological phase transition driven by ferromagnetic exchange interaction and its interplay with spin-orbit-coupling, we discuss various symmetry constraints on the nature of mass term and the materialization of these models. We hope this study will shed light on the fundamental theoretical perspectives of quantum anomalous Hall materials.

POLYMER CRYSTALLIZATION, 2021

Fused filament fabrication (FFF) is among the most accessible and rapidly developing additive man... more Fused filament fabrication (FFF) is among the most accessible and rapidly developing additive manufacturing (AM) technologies. Even though amorphous thermoplastic polymers are the elected materials in FFF, semicrystalline polymers would enhance the strength and durability of 3D printed parts. The properties of the

Applied Surface Science, 2021

Highly hydrophobic aluminium surfaces fabricated by chemical etching are investigated by Contact ... more Highly hydrophobic aluminium surfaces fabricated by chemical etching are investigated by Contact Angle Goniometry, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy in order to correlate the wettability of our samples with their morphology at the sub-micrometer scale and with the chemical composition of the very first surface layers. We find that the etched aluminium surfaces have binary structures with nanoscale block-like convexities and hollows, which provide more space for air trapping. We also demonstrate that both hierarchical micro/nanostructures and surface composition endow these surfaces with excellent hydrophobic properties. XPS analysis shows indeed that the contact angle anti-correlates with the amount of metallic aluminium present at the surface, but also confirms the essential role of the adsorption of airborne carbon compounds. The hydrophobic behaviour depends therefore on the combined effects of surface morphology and surface chemistry.

The Journal of Physical Chemistry C, 2020

When imaged by scanning tunneling microscopy (STM) at constant current under nontopographic condi... more When imaged by scanning tunneling microscopy (STM) at constant current under nontopographic conditions, nanosized MgO islands grown on Ag(100) may show a fractal dark internal structure and/or appear embedded in the surface. On the contrary, when imaged under topographic conditions, the same islands appear as nearly flat plateaus. Islands showing different contrast and a different contrast dependence on sample bias have been often reported in the literature, but a thorough explanation is still missing. Here we demonstrate, on the basis of of experimental data and computational results, that such structure is due to the accumulation of oxygen at the MgO islands− substrate interface. Interestingly, interfacial oxygen concentrates at the center of the islands.

Physical Chemistry Chemical Physics, 2018

The structure and electronic properties of carbon-based nanostructures obtained by metal surface ... more The structure and electronic properties of carbon-based nanostructures obtained by metal surface assisted synthesis is highly dependent on the nature of the precursor molecule.

Applied Surface Science, 2020

We report here on the oxidation of monolayer FeO islands on Pt(1 1 1) into the highly-reactive Fe... more We report here on the oxidation of monolayer FeO islands on Pt(1 1 1) into the highly-reactive FeO 2-x phase by high-temperature oxidation under Ultra High Vacuum (UHV) conditions. The chemical composition and characteristic phonon modes of both FeO and FeO 2-x films were investigated by X-ray photoemission Spectroscopy (XPS) and High Resolution Electron Energy Loss Spectroscopy (HREELS). The reactivity and thermal stability of the "oxygen-rich" FeO 2-x phase were studied with respect to the CO oxidation reaction at 450 K and to annealing in UHV at 563 K, respectively. By performing repeated oxidation/reduction cycles, we have identified the vibrational mode at 76 meV as the unique signature of the FeO 2-x phase and confirmed the already reported ability of CO to reduce such oxide at 450 K. The latter process is not fully reversible, suggesting a modification of the active sites upon CO adsorption.

The Journal of Physical Chemistry C, 2019

Ni nanoclusters up to 30 Å in diameter are grown by Ni deposition on ultrathin MgO/Ag(100) films ... more Ni nanoclusters up to 30 Å in diameter are grown by Ni deposition on ultrathin MgO/Ag(100) films at different temperature and characterized by combining low temperature scanning tunnelling microscopy with photoemission and vibrational spectroscopies. At 200 K both small Ni x O y aggregates and 2D Ni nanoparticles of average size close to 12 Å form. The latter have a metallic nature and efficiently catalyze CO dissociation at 200 K. When Ni is deposited at 300 K, only larger 3D Ni clusters are observed.

Physical Review B, 2018

Recently it was demonstrated that atomic oxygen can cause the extraction of substrate atoms off m... more Recently it was demonstrated that atomic oxygen can cause the extraction of substrate atoms off metal surfaces thus generating chemically different active sites. For Ag(110) this process occurs when O 2 is dosed at 175 K leading, at low coverage, to the formation of single Ag vacancies. Vacancy creation proceeds thereby via the formation of O-AgO complexes, which involve a local reconstruction of the surface and ignite the disruption of the Ag substrate. In this paper, we report on the details of such processes and on the isolated structures formed by the O adatoms in the limit of very low coverage. We employ scanning tunnelling microscopy and density functional theory to unravel the complex structures of O/Ag(110) which are transiently present under specific reaction conditions. A variety of features such as isolated grey dots, sombreros, shallow grey and white structures oriented along [001] and [11 0], grey stripes, and lozenges were identified and assigned to O adatoms in different configurations. The zigzag chains interact strongly with the STM tip and are easily disrupted, giving rise to highly mobile, sombrero shaped, isolated O adatoms also far away from the scanned area, i.e. from the current injection spot. Around 200 K, not only Ag vacancies, which are mobile with anisotropic migration, can merge together into rather complex features, but also the mobile Ag atoms are trapped by O adatoms, thus facilitating the formation of an oxygendecorated Ag chain along [001] which ultimately induces the well-known added row reconstruction.

Physical Review Letters, 2017

The reconstruction and modification of metal surfaces upon O 2 adsorption plays an important role... more The reconstruction and modification of metal surfaces upon O 2 adsorption plays an important role in oxidation processes and in gauging their catalytic activity. Here, we show by employing scanning tunneling microscopy and ab-initio density functional theory that Ag atoms are extracted from pristine (110) terraces upon O 2 dissociation, resulting in vacancies and in AgO complexes. The substrate roughening generates under-coordinated atoms and opens pathways to the Ag subsurface layer. With increasing O coverage, multiple vacancies give rise to remarkable structures. The mechanism is expected to be very general depending on the delicate interplay of energy and entropy, so that it may be active for other materials at different temperatures.

Carbon, 2017

We present here a novel approach to achieve the selective formation of different in-plane boron-n... more We present here a novel approach to achieve the selective formation of different in-plane boron-nitrogen-carbon heterostructures on Pt(111) using a single molecular precursor, namely dimethylamine borane (DMAB). Through thermally activated decomposition and sequential bond activation it is possible to control intermolecular coupling and obtain alternatively a quasi-freestanding continuous monolayer formed by complementary hexagonal boron nitride and graphene (G)

The Journal of Chemical Physics, 2017

Free standing graphene is chemically inert but, as recently demonstrated, CO chemisorption occurs... more Free standing graphene is chemically inert but, as recently demonstrated, CO chemisorption occurs at low crystal temperature on the single layer grown by ethene dehydrogenation on Ni(111). Such layer is inhomogeneous since different phases coexist, the relative abundance of which depends on the growth conditions. Here we show by X ray photoemission and high resolution electron energy loss spectroscopies that the attained CO coverage depends strongly on the relative weight of the different phases as well as on the concentration of carbon in the Ni subsurface region. Our data show that the chemical reactivity is hampered by the carbon content in the substrate. The correlation between the amount of adsorbed CO and the weight of the different graphene phases indicates that the top-fcc configuration is the most reactive.

Physical Chemistry Chemical Physics, 2016

We investigate CO adsorption at single vacancies of graphene supported on Ni(111) and polycrystal... more We investigate CO adsorption at single vacancies of graphene supported on Ni(111) and polycrystalline Cu.

Nanoscale, 2016

High-resolution and temperature programmed synchrotron-excited XPS measurements were carried out ... more High-resolution and temperature programmed synchrotron-excited XPS measurements were carried out at the BACH beamline at Elettra synchrotron (Trieste, Italy), in an UHV chamber with the base pressure below 1×10-9 mbar and equipped with a hemispherical electron energy analyzer (VG Scienta model R3000). The sample normal, the X-ray beam and photoelectron emission direction were all in the same horizontal plane. The photoemission Electronic Supplementary Material (ESI) for Nanoscale.

Surface Science, 2010

The infrared spectra of MgO smoke exposed to water are compared to high-resolution electron energ... more The infrared spectra of MgO smoke exposed to water are compared to high-resolution electron energy loss spectra (HREELS) of hydroxylated ultrathin MgO(1 0 0)/Ag(1 0 0) films. Very similar bands are observed at 3458-3480 cm À1 and 3710-3714 cm À1. On the basis of first principle calculations, these bands are interpreted as the stretching modes of the two distinct OH groups that are formed at monatomic steps parallel to h1 0 0i crystallographic directions. The lower frequency band is due to H adsorbed on O at the step edge, while the higher frequency one originates from OH groups that are twofold coordinated with Mg. Consistently, scanning tunnelling microscopy images of MgO films, prepared in similar conditions as during the HREELS experiments, show that the MgO/Ag(1 0 0) island edges are mainly nonpolar, i.e. oriented along the h1 0 0i direction. In spite of that, a minor contribution to the OH-stretch intensity from hydroxylated polar h1 1 0i steps cannot be excluded; for such geometry density functional theory predicts indeed a single OH species with a vibrational frequency very close to the high-frequency band of OH adsorbed at h1 0 0i steps.

Langmuir, 2010

Self-assembly of organic molecules at metal surfaces is of greatest importance in nanoscience; in... more Self-assembly of organic molecules at metal surfaces is of greatest importance in nanoscience; in fact, it opens new perspectives in the field of molecular electronics and in the study of biocompatible materials. Combining an experimental low-temperature scanning tunneling microscopy investigation with ab initio calculations, we succeeded to describe in detail (S)-glutamic acid adsorption on Ag(100) at T = 350 K. We find that (S)-glutamic acid organizes in a squared structure and, at variance with the majority of cases reported in literature, it adsorbs in the neutral form, 4.6 Å above the surface plane. The interaction with the poorly reactive Ag substrate is only due to weak van der Waals forces, while H-bonds between carboxyl groups and the formation of a OCOH-OCOH-OCOH-OCOH cycle at the vertex of the squares are the main responsible for the self-assembly.