A5081957649- Advanced Chemical Physics Studies
- Catalytic Processes in Materials Science
- Electron and X-Ray Spectroscopy Techniques
- Graphene research and applications
- Surface and Thin Film Phenomena
- Semiconductor materials and devices
- nanoparticles nucleation surface interactions
- Catalysis and Oxidation Reactions
- Ammonia Synthesis and Nitrogen Reduction
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Machine Learning in Materials Science
- Magnetic properties of thin films
- X-ray Spectroscopy and Fluorescence Analysis
- Advancements in Battery Materials
- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- Boron and Carbon Nanomaterials Research
- X-ray Diffraction in Crystallography
- Diamond and Carbon-based Materials Research
- Spectroscopy and Quantum Chemical Studies
- Carbon Nanotubes in Composites
- Electronic and Structural Properties of Oxides
- Theoretical and Computational Physics
- Ion-surface interactions and analysis
Elettra-Sincrotrone Trieste S.C.p.A.
2016-2025
University of Trieste
2016-2025
Clínica Sagrada Esperança
2022
AREA Science Park
2012-2021
ALBA Synchrotron (Spain)
2019
Sapienza University of Rome
2019
Istituto Officina dei Materiali
2010-2017
Scuola Internazionale Superiore di Studi Avanzati
2007-2009
National Interuniversity Consortium of Materials Science and Technology
2008-2009
University College London
2009
Graphene is easily produced by thermally reducing graphene oxide. However, defect formation in the C network during deoxygenation compromises charge carrier mobility reduced material. Understanding mechanisms of thermal reactions essential for defining alternative routes able to limit density defects generated carbon evolution. Here, we identify a dual path mechanism reduction oxide driven oxygen coverage: at low surface density, O atoms adsorbed as epoxy groups evolve O2 leaving unmodified....
Using photoemission spectroscopy techniques, we show that oxygen intercalation is achieved on an extended layer of epitaxial graphene Ir(111), which results in the "lifting" and its decoupling from metal substrate. The adsorption below proceeds as clean giving only a slightly higher coverage. Upon lifting, C 1s signal shows downshift binding energy, due to charge transfer oxygen-covered surface. Moreover, characteristic spectral signatures graphene-substrate interaction valence band are...
By combining high-resolution photoelectron spectroscopy and ab initio calculations, we show that carbon nanoislands formed during the growth of a long-range ordered graphene layer on Ir(111) assume peculiar domelike shape. The understanding unusual mechanism these C clusters, which represent an intermediate phase between strongly coupled carbidic quasi-free-standing layer, can provide information for rational design graphenelike systems at nanoscale.
The chemisorption of O atoms on graphite and the thermal reduction oxidized surface were studied by means high energy resolution photoelectron spectroscopy with synchrotron radiation. C 1s core levels valence band spectra used to identify different oxidizing species evaluate extension sp2 conjugation as a function oxidation time annealing temperature. We found that epoxy groups are dominant only at low stage, ethers semiquinones form proceeds. evolution ether/epoxy ratio increasing oxygen...
By using ab initio molecular dynamics calculations, we show that even where the graphene lattice constant contracts, as previously reported for freestanding below room temperature, average carbon-carbon distance increases with in both free and supported graphene. This results a larger corrugation at higher which can affect interaction between supporting substrate. For weakly interacting system graphene/Ir(111), confirm an experimental approach gives direct access to interatomic distances.
We demonstrate that the key step for reaction of CO 2 with hydrogen on Ni(110) is a change activated molecule coordination to metal surface. At 90 K, negatively charged and chemically bonded via carbon atom. When temperature increased H approaches, H-CO complex flips binds surface through two oxygen atoms, while atom, thus yielding formate. provide atomic-level description this process by means conventional ultrahigh vacuum science techniques combined density functional theory calculations...
Metal-organic coordination interactions are prime candidates for the formation of self-assembled, nanometer-scale periodic networks with room-temperature structural stability. We present X-ray photoelectron spectroscopy measurements such at Cu(100) surface which provide clear evidence genuine metal-organic coordination. This is evident as binding energy shifts in O 1s and Fe 3p peaks, corresponding to atoms involved Our results first charge-transfer surfaces demonstrate a well-defined...
High-quality, large-area epitaxial graphene can be grown on metal surfaces but its transport properties cannot exploited because the electrical conduction is dominated by substrate. Here we insulate Ru(0001) a step-wise intercalation of silicon and oxygen, eventual formation SiO$_2$ layer between metal. We follow reaction steps x-ray photoemission spectroscopy demonstrate insulation using nano-scale multipoint probe technique.
We have performed high resolution XPS experiments of the Ru(0001) surface, both clean and covered with well-defined amounts oxygen up to 1 ML coverage. For surface we detected two distinct components in Ru 3d_{5/2} core level spectra, for which a definite assignment was made using Angle-Scan Photoelectron Diffraction approach. p(2x2), p(2x1), (2x2)-3O (1x1)-O structures found peaks are shifted eV higher binding energies. Very good agreement density functional theory calculations these...
We report on a novel approach to determine the relationship between corrugation and thermal stability of epitaxial graphene grown strongly interacting substrate. According our density functional theory calculations, C single layer Re(0001) is corrugated, with buckling 1.6 Å, yielding simulated 1s core level spectrum which in excellent agreement experimental one. found that closely knit network: C-C bond breaking favored buckled regions moiré cell, though it requires presence diffusing vacancies.
The nanoscale description of the reaction pathways and role intermediate species involved in a chemical process is crucial milestone for tailoring more active, stable, cheaper catalysts, thus providing "reaction engineering" capabilities. This level insight has not been achieved yet catalytic hydrogenation CO2 on Ni enormous environmental relevance. We present thorough atomic-scale mechanisms this reaction, studied under controlled conditions model catalyst, clarifying long-standing debate...
The electron-phonon coupling in potassium-doped graphene on Ir(111) is studied via the renormalization of pi* band near Fermi level, using angle-resolved photoemission spectroscopy. found to be fairly weak and almost isotropic, with a mass enhancement parameter lambda= 0.28(6) for both K-M K-G direction. These results are agree well recent first principles calculations.
We present a study on the growth and characterization of high-quality single-layer MoS2 with single orientation, i.e. without presence mirror domains. This orientation layer is established by means x-ray photoelectron diffraction. The high quality evidenced combining scanning tunneling microscopy spectroscopy measurements. Spin- angle-resolved photoemission experiments performed sample revealed complete spin-polarization valence band states near K -K points Brillouin zone. These findings...
Combined fast X-ray photoelectron spectroscopy and density functional theory calculations reveal the presence of two types hydrogen adsorbate structures at graphene/Ir(111) interface, namely, graphane-like islands dimer structures. While former give rise to a periodic pattern, dimers tend destroy periodicity. Our data distinctive growth rates stability both structures, thereby allowing one obtain well-defined patterns clusters. The ability control manipulate formation size on graphene...
We investigate the structure of epitaxially grown hexagonal boron nitride (h-BN) on Ir(111) by chemical vapor deposition borazine. Using photoelectron diffraction spectroscopy, we unambiguously show that a single-domain h-BN monolayer can be synthesized cyclic dose high-purity borazine onto metal substrate at room temperature followed annealing T=1270 K, this method giving rise to pattern with 3-fold symmetry. In contrast, high-temperature (T=1070 K) results in formed domains opposite...
The nature of bonding in amorphous carbon nitride was studied by synchrotron-radiation photoemission spectroscopy and near-edge x-ray-absorption fine structure. experimental data are compared with theoretical calculations chemical shifts, the relative importance initial final state effects is discussed. Bond lengths determined from position ${\ensuremath{\sigma}}^{*}$ resonance obtained results suggest ${\mathrm{sp}}^{2}$ hybridization. evidence presented this paper supports another...
We show that dissociative oxygen adsorption on Ag(001) induces below room temperature a missing row $2\sqrt{2}\ifmmode\times\else\texttimes\fi{}\sqrt{2}$ reconstruction of the substrate. As demonstrated by analysis photoelectron diffraction patterns, atoms sit thereby in $c(2\ifmmode\times\else\texttimes\fi{}2)$ arrangement previous fourfold hollow sites nearly coplanar with Ag atoms, while rows substrate are removed along $[100]$ directions. Annealing crystal above 350 K restores...
We present a combined experimental and theoretical study of the $\mathrm{C}{\mathrm{O}}_{2}$ interaction with Ni(110) surface. Photoelectron spectroscopy, temperature-programmed desorption, high-resolution electron energy loss spectroscopy measurements are performed at different coverages for increasing surface temperature after adsorption $90\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ aim to competing processes dissociation desorption. Simulations within framework density functional theory using...
The formation of a hexagonal boron nitride (h-BN) layer through dissociation borazine (B3N3H6) molecules on Ir(111) has been investigated by combination X-ray photoelectron spectroscopy, near-edge absorption fine structure, temperature-programmed desorption, and low-energy electron diffraction. At low temperature (T = 170 K), molecular adsorption occurs with the plane benzene-like ring parallel to substrate. Dehydrogenation is observed at temperatures higher than 250 K extends up 900 K,...
Iron-phthalocyanine molecules self-assemble on the moiré pattern of graphene/Ir(111) as a flat and weakly interacting layer, determined by core-level photoemission absorption spectroscopy. The graphene buffer layer decouples FePc two-dimensional structure from underlying metal; electronic molecular macrocycles is preserved; Fe-L2,3 edges present narrower slightly modified resonances at single-layer coverage with respect to thin film. induces slight electron doping Ir-supported resulting in...
The interaction of submonolayer quantities size-selected and soft-landed Tan (n = 4, 5, 6, 8, 13) clusters with Pt(111) is investigated employing high-resolution X-ray photoelectron spectroscopy (HR-XPS), scanning tunneling microscopy (STM), density functional theory (DFT) simulations. deposited are monodispersed stable under ultrahigh vacuum (UHV) conditions at 40 K. They display a size-specific trend in photoemission spectra, which reasoned terms the distinct plane coordination Ta atoms...