1,721,281 research outputs found
Oxocluster-reinforced organic-inorganic hybrid materials: effect of transition metal oxoclusters on structural and functional properties
No full textThe focus of this Highlight is on the structural and functional properties which organically modified transition oxoclusters can provide, once embedded into a polymer matrix, to the resulting hybrid materials. Some selected case studies are discussed to highlight the role of these polynuclear inorganic building blocks in determining appealing material properties.The focus of this Highlight is on the structural and functional properties which organically
modified transition oxoclusters can provide, once embedded into a polymer matrix, to the
resulting hybrid materials. Some selected case studies are discussed to highlight the role of
these polynuclear inorganic building blocks in determining appealing material properties
A Mature Tool to Address New Challenges: Harnessing Coordination Chemistry for The Sustainable Copper Recovery from Industrial and E‐Waste in The Age of Energy Transition
No full textCopper is arguably one of the most strategic metals for the energy transition, particularly in the shift from fossil fuel-based engines to sustainable and renewable energy sources, with related and broader electrification efforts. While global copper mineral resources are far from depleted, their uneven distribution poses significant supply risks, especially in regions like Europe. In 2023, the European Union (EU) recognized this risk by designating copper as a strategic raw material (SRM), highlighting the need for innovative copper recovery processes. Copper recovery from industrial and electronic waste has been approached through various methods, primarily categorized into pyrometallurgy and solvo- and hydrometallurgy. The latter offers greater tunability and potential for sustainability, particularly when leveraging coordination chemistry. This review focuses on the most promising hydrometallurgical processes for copper recovery from industrial and e-waste (i. e., electronic waste), with a special emphasis on the role of coordination chemistry in supporting these methods. We posed particular focus on the adaptability and versatility of the coordination chemistry-based processes to the highly heterogenous composition of the copper-containing wastes
XPS as a powerful tool to investigate the surface properties of simple and mixed metal oxides
No full textXPS is a well established surface sensitive method for the analysis of solid materials,
allowing the determination of surface composition and the assessment of oxidation state
and chemical environment of the different species. In fact, core level XPS is highly
sensitive to the chemical environment, i.e. the binding energy may be strongly dependent
on the oxidation state of the investigated ion, as well as on the neighbouring atoms.
Oxide-based materials (simple, multicomponent and composites), are a fascinating
and technologically appealing class of materials, exhibiting a huge variety of chemical,
structural, optical, magnetic, electric and electronic properties. Since in oxides the
functional properties are mainly related to the complex interplay among composition,
microstructure, shape, characteristic size, charge density, chemical environment, presence
of defects etc., the understanding of their actual chemical nature and electronic structure
is a primary concern to fully exploit their functionalities in different fields.
In this chapter, after a general overview on metal oxides and on their electronic
structure and peculiarities, the application of XPS to their investigation will be introduced
and discussed and some selected application fields will be considered.
The effect of ion sputtering in oxides will be moreover shortly examined.
Furthermore, in this contribution, the issues related to the determination of the actual
chemical state of metal species in mixed oxides will be also extensively addressed and
discussed. The possibility of XPS to evidence the presence of M-O-M’ mixed bonds will
be highlighted.
In the second part of the chapter, several different selected case studies will be
analysed in detail, which deal with different oxide systems: simple oxides, also in mixedvalence
state, (ZnO, WO3, CuxOy, VxOy), mixed oxides (e.g. SiO2-HfO2, SiO2-ZrO2, SiO2-TiO2, ZrO2-TiO2), doped oxides (FexOy:TiO2, M(Pt, Ag):TiO2, M (Au, Pt, Pd,
Rh):SiO2).
In particular, the use of this method for the investigation of the chemical composition
of different typologies of surfaces (thin films, powders) will be discussed.
A further aspect to be dealt with is the perspective combination of XPS, also at
variable pressure, with other site-specific spectroscopic methods (XAS, XEOL) and
theoretical tools (e.g. DFT), which represents a valuable tool to unravel and predict issues
related to the reactivity and to other functional properties of these materials
Sustainable and very-low-temperature wet-chemistry routes for the synthesis of crystalline inorganic nanostructures
No full textIn this chapter, selected low (T < 200 °C)-temperature wet-chemistry
routes for the synthesis of crystalline inorganic compounds are described and
reviewed, outlining their main features and application fi elds. In particular, the chosen
approaches are hydro/solvothermal synthesis, template-assisted approaches,
nucleation and growth in solution/suspension, microemulsion and miniemulsion.
The described synthetic strategies have been selected since all of them, once optimized
the experimental set-up and conditions, comply with the paradigms of green
chemistry, being based on low (or even room) temperature of processing, on low
chemical consumption (they are all bottom-up approach), in many cases having water
as solvent or dispersing medium. In this regard, environmentally friendly methodologies
for the controlled synthesis of inorganic nanostructures represent a stimulating
research playground, since the use of environmentally friendly, green, cost-effective
and technically sound approaches to inorganic crystalline nanostructures does not
necessarily imply to sacrifi ce the sample crystallinity, purity, and monodispersity
Dielectric investigation of inorganic-organic hybrid film based on zirconium oxocluster-crosslinked PMMA
No full textThrough photocopolymerisation of the cluster Zr4O2(OMc)12 bearing 12 polymerisable groups with methylmethacrylate in a monomer:cluster molar ratio of 50, a novel inorganic-organic hybrid thin film was obtained. The prepared thin film, having a thickness of about 70 mum, was characterised through dielectric spectroscopy. The dielectric spectra of the film were measured at different temperatures (20-73.4 °C) and in the frequency range 20 Hz-1 MHz. The alpha and beta relaxations typical of polyalkylmethacrylate polymers were detected and the electric response mechanisms were investigated by analysing the dielectric spectra in terms of the Davidson-Cole phenomenological equation. Finally, a dielectric constant of 1.93 at 25 °C and 1 kHz was determined. This value classifies this system as a promising dielectric material for the development of electronic devices, such as polymer based field effect transistors
Re-investigation of the thermal decomposition of Co(CO)4SiCl3 adsorbed on silica
No full textEvidence is provided that thermal decomposition of Co(CO)4SiCl3 adsorbed on silica in a hydrogen atmosphere results in the formation of metallic cobalt nanoparticles covered with a Co2SiO4/CoO shell instead of cobalt silicide nanoparticles, as had been reported previously
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