XPS

OSSIDO DI GRAFENE E DERIVATI: CARATTERIZZAZIONE E APPLICAZIONI

OSSIDO DI GRAFENE E DERIVATI: CARATTERIZZAZIONE E APPLICAZIONI

A partire dall’ossido di grafene (GO) vengono sintetizzati suoi derivati variabilmente “ridotti” con metodi chimici, termici ed elettrochimici. Vengono anche preparati materiali ibridi nanostrutturati attraverso reazioni di funzionalizzazione del GO con molecole con funzionalità specifiche (redox, chelanti, sensibilizzanti). Questi materiali vengono investigati mediante spettroscopia di fotoemissione (XPS), UV-vis, Raman, FTIR, elettrochimica, microscopia e calcoli teorici. Le possibili applicazioni sono in ambito biomedico, energetico, ambientale.

Designing cascades of electron transfer processes in multicomponent graphene conjugate

A novel family of nanocarbon‐based materials were designed, synthesized, and probed within the context of charge‐transfer cascades. In details, we implemented fine‐tuned chains of photo‐ and redox‐active constituents. For the first time, we integrated electron‐donating ferrocenes with light‐harvesting /electron‐donating (metallo)porphyrins and electron‐accepting graphene nanoplates (GNP) into multicomponent conjugates. To control the rate of charge flow between the individual building blocks, we bridged them via oligo‐ p ‐phenyleneethynylenes of variable lengths.

Understanding and controlling short- and long-range electron/charge transfer processes in electron donor-acceptor conjugates

We have probed a series of multicomponent electron donor2-donor1-acceptor1 conjugates, both experimentally and computationally. The conjugates are based on the light harvester and primary electron-donor zinc-porphyrin (ZnP, donor1), to whose β-positions a secondary electron-donor ferrocene (Fc, donor2) and the primary electron-acceptor C60-fullerene (C60, acceptor1) are linked via p-phenylene-acetylene bridges of different lengths. This modular approach makes full control over shuttling electrons and holes between C60, ZnP, and Fc possible.

Enhancement of the performance in Li-O2cells of a NiCo2O4based porous positive electrode by Cr(III) doping

Here we discuss the incorporation of Cr(III) as dopant in the spinel lattice of the NiCo2O4cubic phase and its beneficial effect on the electro-catalytic activity of this material in aprotic Li-O2cells. To this aim, we synthesized highly porous carbon-free self-standing electrodes constituted by nanostructured undoped and Cr-doped NiCo2O4grown on open nickel mesh. These materials were characterized by X-ray diffraction, field emission scanning electron microscopy coupled with energy dispersive spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy.

Integration of graphene onto silicon through electrochemical reduction of graphene oxide layers in non-aqueous medium

Wafer-scale integration of reduced graphene oxide with H-terminated Si(1 1 1) surfaces has been accomplished by electrochemical reduction of a thin film of graphene oxide deposited onto Si by drop casting. Two reduction methods have been assayed and carried out in an acetonitrile solution. The initial deposit was subjected either to potential cycling in a 0.1 M TBAPF 6 /CH 3 CN solution at scan rates values of 20 mV s −1 and 50 mV s −1 , or to a potentiostatic polarization at E λ,c = −3 V for 450 s.

Adsorption dynamics of redox active species onto polarized surfaces of sensitized NiO

Mesoporous NiO films were deposited by means of a screen printing technique onto fluorine-doped tin oxide transparent electrodes and consequently sensitized with Erythrosin B (EryB) dye. The obtained colored NiO material was used as a working electrode in a three-electrode cell to study the evolution of the triple semiconductor/dye/electrolyte interface upon electrochemical polarization in dark conditions. The electrolyte was a solution of I3 -/I- in acetonitrile, with the redox couple representing the typical redox shuttle of dye-sensitized solar cells (DSCs).

Core shell investigation of 2-nitroimidazole

Tunability and selectivity of synchrotron radiation have been used to study the excitation and ionization of 2-nitroimidazole at the C, N, and O K-edges. The combination of a set of different measurements (X-ray photoelectron spectroscopy, near-edge photoabsorption spectroscopy, Resonant Auger electron spectroscopy, and mass spectrometry) and computational modeling have successfully disclosed local effects due to the chemical environment on both excitation/ionization and fragmentation of the molecule.

Synthesis of gold and silver nanoparticles functionalized with organic dithiols

In this work commercially available bifunctional organic dithiols, 4,4?-dithiol-biphenyl (BI), 4,4?-dithiolterphenyl (TR) and the on purpose prepared precursor of 4,4?-dithiol-trans-stilbene (ST), have been used for the stabilization of gold and silver nanoparticles (AuNPs and AgNPs). The bifunctional thiols have been chosen with different conjugation length, to prepare interconnected system of nanoparticles in order to achieve a tuning of their optical properties.

X-ray photoelectron spectroscopy investigation of nanoporous NiO electrodes sensitized with Erythrosine B

Nanoporous NiO thin films were prepared onto FTO glass substrates by means of screen-printing and were sensitized with Erythrosine B (EryB) dye. The obtained material was electrochemically treated and characterized with ex-situ X-ray photoelectron spectroscopy in order to gain information beneficial to the application of sensitized NiO as photocathodes of p-type dye-sensitized solar cells (p-DSCs).

Surface properties of nanostructured NiO undergoing electrochemical oxidation in 3-methoxy-propionitrile

Nanostructured nickel oxide (NiO) was deposited in the configuration of thin film (thickness, l = 2–6 m)
onto fluorine-doped tin oxide (FTO) substrates via plasma-assisted rapid discharge sintering (RDS). Electrochemical
cycling of RDS NiO in 3-methoxy-propionitrile (3-MPN) revealed two characteristic peaks
of NiO oxidation which were associated to the surface-confined redox processes Ni(II) ? Ni(III) and

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