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SuperESCA Highlights

The power of surfaces: meta-polyaniline from para-aminophenol

The catalytic properties of the Pt (111) surface allow adsorbed para-aminophenol molecules, upon thermal stimulus, to covalently react each other forming oligomers coupled in a metaconfiguration. The behaviour of the system has been characterized by multiple experimental techniques, including STM, nc-AFM, STS and fast-XPS, and DFT calculations.

Nerea Ruiz del Árbol et al., Angew. Chem. Int. Ed. 59, 23220 (2020).

NO2 desorption from Carbon nanotubes filled with Ni nanoclusters

High-resolution fast XPS allowed verifying that the interaction of nitrogen dioxide with metallicity sorted Single Walled Carbon Nanotubes can be tuned by filling the tubes either with nickel(II) acetylacetonate molecules or with Ni clusters, achieving desorption of NO2 at ambient temperature.

F. Fedi et al., J. Mater. Chem. A 8, 9753 (2020).

Carbon-carbon bond formation on cobalt

High-resolution fast XPS allowed determining the concentration and chemical identity of the surface intermediates that form when the ethylene precursor reacts on the CO pre-covered Co(0001) surface. The results provide insights on C-C bond formation on a cobalt catalyst, an important step in the formation of long chain hydrocarbons in the Fischer-Tropsch process.
C.J. Weststrate et al., Nat. Commun. 11, 750 (2020).

Dual-route hydrogenation of epitaxial graphene

In this study it is investigated the room temperature hydrogenarion of the graphene/Ni(111) system. It is found that at the beginning of hydrogenation H atoms chemisorb on graphene, while at higher H doses intercalation below the graphene layer takes place. Data point out that the amount of intercalated hydrogen can be more than twice larger than the quantity of H that can be adsorbed on the bare Ni(111) surface.
D. Lizzit et al., ACS Nano. 13, 1828 (2019).

Low-dimensional benzotriazole-copper assemblies

A combination of several surface sensitive techniques (NEXAFS, XPS, HREELS and STM) and DFT modelling allowed investigating the interaction of Cu atoms (supported on a less reactive Au(111) surface) with benzotriazole (C6H5N3) which is known to enhance the corrosion resistance of copper.

F. Grillo et al., Nanoscale 11, 13017 (2019).

Tungsten disulfide on Au(111)

In this work, we combined several techniques to provide a characterization of single-layer (SL) WS2 grown on Au(111). In particular, we used x-ray photoelectron diffraction (XPD) to determine the structural properties of the interface, proving that we have a WS2 layer with a single orientation.
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L. Bignardi et al.,  Phys. Rev. Materials 3, 014003 (2019).

Single-oriented epitaxial MoS2

Using a combination of surface science techniques, including XPS, XPD, STM and ARPES we succesfully demonstrate a protocol for the synthesis through physical vapor deposition of SL MoS2 on Au(111) with a single domain orientation featuring large area and a low concentration of defects. The observed complete spin reversal of the states near K and –K points of the Brillouin zone makes this layer ideal for spin-valleytronics applications.
H. Bana et al., 2D Mater. 5, 035012 (2018).

Silicon on Ir(111)

Fast X-ray photoelectron spectroscopy measurements and density functional theory calculations were used to establish whether at low coverage, Si adatoms float on the Ir surface or displace substrate atoms and are incorporated into the metal. The results show that the interface is unstable with respect to the formation of Si–Ir alloys, a behavior that excludes the formation of a silicene layer on the Ir(111) substrate.
M. Satta et al., Nanoscale 10, 7085 (2018).

Stable self-assembled monolayers on ferromagnetic 3d metals

The carboxylic group of prototypical benzoate molecules is found to ensure a thermally robust anchoring and strong electronic coupling of organic monolayers to 3d transition metals such as Ni, Co and Fe, at the same time hindering facile dissociation on these reactive surfaces.
R. Han et al., Chem. Commun. 52, 9805 (2016).

Graphene nanoblisters on nickel

Argon intercalation below a graphene layer grown epitaxially on Ni(111), followed by annealing at 940 K results in the formation of Ar-filled graphene nanoblisters sealed directly to the bare Ni surface. The process was monitored with real-time High-Resolution Photoemission Spectroscopy (HR-XPS) and the atomic structure of the blisters was studied with Scanning Tunneling Microscopy (STM).
R. Larciprete et al., Nano Letters 16, 1808 (2016).

Two-dimensional self-assembly of benzotriazole

Often the physicochemical properties of a material depend on its dimensionality; for organic molecules intermolecular interactions present in the 3D solid may differ from those of 2D or 1D systems. NEXAFS, XPS, HREELS, and LT-STM measurements, combined with DFT modelling, reveal a subtle balance of interactions governing the adsorption of Benzotriazole (BTAH, C6H5N3) on Au(111).
F. Grillo et al., Nanoscale 8, 9167 (2016).

Molecular twisting, lifting and curling

Coronene molecules undergo major conformational changes during surface-assisted dissociation on Ir(111): they tilt upward, then they undergo  a rotation and they settle to form a dome-shaped nanographene.
D. Curcio et al., J. Am. Chem. Soc. 138, 3395 (2016).

Single-oriented domains of h-BN on Ir(111)

Using X-ray Photoelectron Diffraction (XPD) we show that, on the Ir(111) surface, ordinary high-temperature borazine deposition gives rise to an h-BN monolayer formed by fcc and hcp antiparallel domains, while h-BN monolayer with single fcc orientation can be synthesized by dosing borazine at room temperature followed by annealing.
F. Orlando et al., ACS Nano 8, 12063 (2014).

Nitroxides adsorption on carbon nanotubes

XPS and XAS experiments, combined with DFT calculations, revealed that the reactivity of single-walled CNTs towards NOx depends on their metallicity. Ultrapure metallic CNTs are twice more prone to NO2 physisorption than their semiconducting counterparts, while the latter induce more dissociation on the adsorbed NO2.
G. Ruiz-Soria et al., ACS Nano 8, 1375 (2014).

Ultrafast charge transfer to graphene monolayers

The charge transfer (CT) rates of a localized excited electron to graphene monolayers with variable substrate coupling were investigated by the core hole clock (CHC) method with adsorbed argon. CT time (τCT) to Gr depends strongly on Gr-substrate coupling and varies from ~16 fs, for decoupled Gr, to ~2.5 ns for strong coupling.
S. Lizzit et al., ACS Nano 7, 4359 (2013).

Patterning graphene with hydrogen clusters

Combined fast XPS and DFT calculations revealed the presence of two types of hydrogen adsorbate structures at the graphene/Ir(111) interface: graphane-like islands, giving rise to a periodic pattern, and dimers, which tend to destroy the periodicity. Distinctive growth rates and stability of the two types of structures allow well-defined patterns of clusters.
R. Balog et al., ACS Nano 7, 3823 (2013).

Oxygen intercalation below epitaxial graphene

Oxygen intercalation below an extended layer of epitaxial graphene on Ir(111) is demonstrated using  real-time High-Resolution Photoemission Spectroscopy (HR-XPS). The resulting “lifted” graphene is decoupled from the Ir substrate and slightly p-doped as indicated by Angular Resolved Photoemission Spectroscopy (ARPES).
R. Larciprete et al., ACS Nano 6, 9551 (2012).

Tailoring bimetallic alloy surface properties

Complex self-diffusion mechanisms determining key properties of binary alloys can be mostly defined by kinetic rather than energetic effects. In the Ni−Cu system, nanoscale control of these processes close to the surface yields tuning of the material functionality.
M. Rizzi et al., J. Am. Chem. Soc. 134, 16827 (2012).

Transfer-Free Electrical Insulation of Epitaxial Graphene

Stepwise intercalation of silicon and oxygen, allows the synthesis of a SiO2 film below a graphene layer epitaxially grown on Ru(0001). We used photoemission spectroscopy to follow the reaction steps, which lead to a graphene layer electrically insulated from the substrate, as demonstrated by surface resistance data.
S. Lizzit et al., Nano Lett. 12, 4503 (2012).

Rh nanoclusters on graphene template

Graphene-supported Rh nanocluster assemblies and their geometry dependent electronic structure have been studied  by combining high-energy resolution core level photoelectron spectroscopy, scanning tunneling microscopy, and density functional theory.
A.. Cavallin et al., ACS Nano 6, 3034 (2012).

H-bond mediated dissociation of ammonia on Si(001)

By combining DFT calculation and fast XPS measurements we demonstrate that the low temperature dissociation of NH3 molecules chemisorbed on Si(001)-2x1 is driven by the continuous flux of ammonia molecules from the gas phase.
M. Satta et al., Phys. Rev. Lett. 109, 036102 (2012).

Thermal reduction of graphene oxide

By combining time-resolved photoemission spectroscopy and ab initio calculations we identified a dual path mechanism in the thermal reduction of graphene oxide: at low O coverage, epoxy groups evolve as O2 leaving the C network unmodified, while at higher coverage, other O-containing species form opens competing reaction channels, which consume the C backbone.
R. Larciprete et al., J. Am. Chem. Soc. 133, 17315 (2011).

Thermal expansion of graphene

We have studied the thermal expansion of graphene by using a combination of ab initio molecular dynamics calculations and high-resolution core level photoelectron spectroscopy measurements.
M. Pozzo et al., Phys. Rev. Lett. 106, 135501 (2011)

Chemical reactivity of undercoordinated Rh atoms

A remarkable linear relationship between the surface core level shifts (SCLS) and the corresponding induced d-band center shifts of highly undercoordinated Rh atoms on a Pt surface indicates SCLS as reliable experimental descriptors of chemical reactivity.
A. Baraldi et al., J. Phys. Chem. C 115, 3378 (2011).

Band dispersion in the deep 1s core level of graphene

The observed emission-angle-dependent binding energy modulation in graphene C 1s photoemission spectra indicates band formation even for deep core levels.

S. Lizzit et al., Nature Physics 6, 345 (2010).

The surface structure of Rh oxide

The surface and interface structure of the RhO2 ultra-thin film grown on Rh(100) has been investigated by means of x-ray photoelectron diffraction. Analysis of 2D angular distribution intensities of the O1s and Rh3d5/2 chemically shifted core levels allowed us to reveal a rippled buckling of the metal surface.
R. R. Zhan et al., J. Chem. Phys. 133, 214701 (2010).

Dome-shaped carbon nanoislands on Ir(111)

We studied the first stages of graphene growth on Ir(111) with high-resolution XPS combined with DFT calculations. We demonstrate that the geodesic-like carbon nanoislands which form at low C coverage interact with the substrate only at the periphery.
P. Lacovig et al., Phys. Rev. Lett. 103, 166101 (2009).

Ultima modifica il Venerdì, 22 Gennaio 2021 16:30