Designed NiMoC@C and NiFeMo2C@C core-shell nanoparticles for oxygen evolution in alkaline media.

Electrochemical water splitting is one of the most promising and clean ways to produce hydrogen as a fuel. Herein, we present a facile and versatile strategy for synthesizing non-precious transition binary and ternary metal-based catalysts encapsulated in a graphitic carbon shell. NiMoC@C and NiFeMo2C@C were prepared via a simple sol-gel based method for application in the Oxygen Evolution Reaction (OER). The conductive carbon layer surrounding the metals was introduced to improve electron transport throughout the catalyst structure. This multifunctional structure showed synergistic effects, possess a larger number of active sites and enhanced electrochemical durability. Structural analysis indicated that the metallic phases were encapsulated in the graphitic shell. Experimental results demonstrated that the optimal core-shell material NiFeMo2C@C exhibited the best catalytic performance for the OER in 0.5 M KOH, reaching a current density of 10 mA cm-2 at low overpotential of 292 mV for the OER, superior to the benchmark IrO2 nanoparticles. The good performances and stability of these OER electrocatalysts, alongside an easily scalable procedure makes these systems ideal for industrial purposes.

Cutting-Edge Electrocatalysts for CO2RR.

A world-wide growing concern relates to the rising levels of CO2 in the atmosphere that leads to devastating consequences for our environment. In addition to reducing emissions, one alternative strategy is the conversion of CO2 (via the CO2 Reduction Reaction, or CO2RR) into added-value chemicals, such as CO, HCOOH, C2H5OH, CH4, and more. Although this strategy is currently not economically feasible due to the high stability of the CO2 molecule, significant progress has been made to optimize this electrochemical conversion, especially in terms of finding a performing catalyst. In fact, many noble and non-noble metal-based systems have been investigated but achieving CO2 conversion with high faradaic efficiency (FE), high selectivity towards specific products (e.g., hydrocarbons), and maintaining long-term stability is still challenging. The situation is also aggravated by a concomitant hydrogen production reaction (HER), together with the cost and/or scarcity of some catalysts. This review aims to present, among the most recent studies, some of the best-performing catalysts for CO2RR. By discussing the reasons behind their performances, and relating them to their composition and structural features, some key qualities for an "optimal catalyst" can be defined, which, in turn, will help render the conversion of CO2 a practical, as well as economically feasible process.

Bone Marrow Mesenchymal Stromal/Stem Cell-Derived Extracellular Vesicles Promote Corneal Wound Repair by Regulating Inflammation and Angiogenesis.

Severe corneal damage leads to complete vision loss, thereby affecting life quality and impinging heavily on the healthcare system. Current clinical approaches to manage corneal wounds suffer from severe drawbacks, thus requiring the development of alternative strategies. Of late, mesenchymal stromal/stem cell (MSC)-derived extracellular vesicles (EVs) have become a promising tool in the ophthalmic field. In the present study, we topically delivered bone-marrow-derived MSC-EVs (BMSC-EVs), embedded in methylcellulose, in a murine model of alkali-burn-induced corneal damage in order to evaluate their role in corneal repair through histological and molecular analyses, with the support of magnetic resonance imaging. Our data show that BMSC-EVs, used for the first time in this specific formulation on the damaged cornea, modulate cell death, inflammation and angiogenetic programs in the injured tissue, thus leading to a faster recovery of corneal damage. These results were confirmed on cadaveric donor-derived human corneal epithelial cells in vitro. Thus, BMSC-EVs modulate corneal repair dynamics and are promising as a new cell-free approach for intervening on burn wounds, especially in the avascularized region of the eye.

Regenerative Approaches and Future Trends for the Treatment of Corneal Burn Injuries.

Ocular chemical and thermal burns are frequent causes of hospitalization and require immediate interventions and care. Various surgical and pharmacological treatment strategies are employed according to damage severity. Controlling inflammation and neovascularization while promoting normal ocular surface anatomy and function restoration is the principal aim. In the most severe cases, when epithelial healing is severely affected, reconstruction of the ocular surface may be a valid option, which, however, requires expertise, adequate instruments, and qualified donors. Numerous endogenous and exogenous strategies have been considered for corneal repair. Among these, stem cells and their derivatives have offered numerous attractive possibilities in finding an effective way in stimulating corneal regeneration. Limbal epithelial stem cells and mesenchymal cells from the ocular tissue as well as from various sources have demonstrated their effectiveness in dampening neovascularization, scarring, and inflammation, while promoting epithelialization of the injured cornea. Moreover, a plethora of cytokines and growth factors, and extracellular vesicles, which constitute the secretome of these cells, work in concert to enhance wound healing. In this review, we provide an update on the recent potential therapeutic avenues and clinical applications of stem cells and their products in corneal regeneration after burn injury, as well as current imaging strategies for monitoring therapeutic efficacy and damage resolution.

Multimetallic Oxynitrides Nanoparticles for a New Generation of Photocatalysts.

A versatile synthetic strategy for the preparation of multimetallic oxynitrides has been designed and here exemplarily discussed considering the preparation of nanoscaled zinc-gallium oxynitrides and zinc-gallium-indium oxynitrides, two important photocatalysts of new generation, which proved to be active in key energy related processes from pollutant decomposition to overall water splitting. The synthesis presented here allows the preparation of small nanoparticles (less than 20 nm in average diameter), well-defined in size and shape, yet highly crystalline and with the highest surface area reported so far (up to 80 m2 g-1 ). X-ray diffraction studies show that the final material is not a mixture of single oxides but a distinctive compound. The photocatalytic properties of the oxynitrides have been tested towards the decomposition of an organic dye (as a model reaction for the decomposition of air pollutants), showing better photocatalytic performances than the corresponding pure phases (reaction constant 0.22 h-1 ), whereas almost no reaction was observed in absence of catalyst or in the dark. The photocatalysts have been also tested for H2 evolution (semi-reaction of the water splitting process) with results comparable to the best literature values but leaving room for further improvement.

HfN Nanoparticles: An Unexplored Catalyst for the Electrocatalytic Oxygen Evolution Reaction.

Water electrolysis is one of the most promising methods to produce H2 and O2 as high potential fuels. Comparing the two half-reactions, the oxygen evolution reaction (OER) is the more difficult to be optimized and still relies on expensive noble metal-based catalysts such as Ru or Ir. In this paper, we prepared nanoparticles of HfN and Hf2 ON2 and tested them for the OER for the first time. The HfN sample, in particular, showed the highest activity, requiring an overpotential of only 358 mV at 10 mA cm-2 in Fe-free electrolyte and, above all, exhibiting long-term stability. This result places this system amongst one of the most promising catalysts for OER tested to date, in terms of sustainability, activity and stability. The prepared nanoparticles are small (less than 15 nm in diameter), well-defined in shape and crystalline, and were characterised before and after electrochemical testing also via electron microscopy (EM), powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS).

Non-conventional Ce:YAG nanostructures via urea complexes.

Ce:YAG nanostructures (Ce:YAG = Cerium in Yttrium Aluminium Garnet), easy to control and shape, have been prepared via templating approach using natural and synthetic materials (i.e. paper, cotton wool and glass wool) previously soaked with a gel-like metals precursor and then thermally treated to achieve the wished morphology. The final material, otherwise difficult to process, can be easily moulded, it is lightweight, portable and forms, at the nanoscale, homogeneous layers of interconnected but not agglomerated nanoparticles (15 ± 5 nm). Using the same synthetic route, called Urea-Glass-Route, but in absence of a template, extremely pure Ce:YAG nanoparticle (45 ± 5 nm) can be also prepared, highly crystalline and well-defined in size and shape. Both structural and optical properties of the final materials were investigated, showing high optical quality. The support allows the production of a multifunctional material with mouldable shape and potential lighting application for large structures combining the strength, chemical durability, fire resistance, and translucency of glass fibres. Last, but not least, the synthetic path also allows an easy scaling up of the process: the first, key step for practical application of nanosized rare-earth doped YAG on large scale.

Iron Carbide@Carbon Nanocomposites: A Tool Box of Functional Materials.

Iron carbide (Fe3C) is a ceramic magnetic material with high potential for applications in different fields, including catalysis, medicine imaging, coatings, and sensors. Despite its interesting properties, it is still somehow largely unexplored, probably due to challenging synthetic conditions. In this contribution, we present a sol-gel-based method that allows preparing different Fe3C@C nanocomposites with tailored properties for specific applications, in particular, we have focused on and discussed potential uses for adsorption of noxious gas and waste removal. Nanocomposites were prepared using readily available and "green" sources, such as urea, simple and complex sugars, and chitosan. The nanocomposite prepared from chitosan was found to be more efficient for CO2 uptake, while the sample synthetized from cellulose had optimal capability for dye absorption and waste oil removal from water.

Branch-Like Iron Nitride and Carbide Magnetic Fibres Using an Electrospinning Technique.

Fe3 N and Fe3 C nanocomposites have a wide range of applications thanks to their ceramic nature, magnetic properties, conductivity and catalytic activity, just to cite some. In many fields optimal performances are ensured by crystallinity, homogeneity and hierarchical organization. In the present paper, crystalline, magnetic and well-defined nanofibres of iron nitride and iron carbide/carbon nanocomposite with tunable composition and size were prepared via electrospinning. The starting polymeric material was directly electrospun into fibres and then calcined, leading to a highly homogeneous final product of nanoparticles along the fibres (both outside and inside). A mechanistic study was undertaken and here discussed. The magnetic properties of the as-prepared nanofibres were also studied. The as-prepared final fibre mat composite material can serve as active catalyst, for example, in oxygen reduction reaction (where nanofibres outperformed mere nanoparticles), it can serve as functional support for classical catalytic processes or, thanks to its magnetic properties, can be applied in magnetic-field assisted separation or as magneto-active membranes.

Aerosol-Assisted Synthesis of Porous TiNx Oy @C Nanocomposites.

Porous TiNx Oy -based particles were synthesized by an aerosol spray process. At first, the starting sol solution containing the metal precursor and the nitrogen source is sprayed to form an aerosol that is subsequently pyrolysed at different temperatures. The obtained dried particles are an amorphous coordination "polymer" rich in carbon and nitrogen. These "glassy" particles are finally thermally treated at 800 °C, promoting the crystallization of the particles and the release of a major part of the carbon. As the particles keep their original shape, carbon loss and density increase during the crystallization step and lead to the development of an accessible pore structure. The process was analyzed and extended to the synthesis of other metal nitrides, such as VN and W2 N, thereby showing its general validity for the production of functional nanocrystalline nitride ceramics with high porosity still occupying a relatively small volume, and otherwise not easily accessible.

Enhanced catalysis of the electrochemical hydrogen evolution reaction using composites of molybdenum-based compounds, gold nanoparticles and carbon.

Molybdenum nitride has been recently reported to interact synergistically with gold to show an enhanced activity for the electrochemical hydrogen evolution reaction (2H(+) + 2e(-)→ H2, HER). In this work, we elucidated the roles of nitrogen, carbon, molybdenum and gold on this observed phenomenon. Composites of Mo-based compounds, carbon black (black pearl 2000) and/or Au nanoparticles (AuNP) were prepared, and their activities for the HER in a 0.5 M H2SO4 electrolyte were measured using linear sweep voltammetry. We show and discuss here for the first time that, while the presence of carbon is necessary for the synergy phenomenon, the nitrogen atoms present in the compounds play no apparent role in this synergy. In fact, all the compounds containing Mo, namely Mo2N, MoB and metallic Mo(0), exhibited extensive synergy with Au for the HER. A hypothesis for the enhanced catalysis of H2 evolution by the mixed metal composites is proposed and discussed.

Neuronal ceroid lipofuscinosis associated with an MFSD8 mutation in Chihuahuas.

The neuronal ceroid lipofuscinoses (NCLs) are hereditary neurodegenerative disorders characterized by progressive declines in neurological functions, seizures, and premature death. NCLs result from mutations in at least 13 different genes. Canine versions of the NCLs can serve as important models in developing effective therapeutic interventions for these diseases. NCLs have been described in a number of dog breeds, including Chihuahuas. Studies were undertaken to further characterize the pathology of Chihuahua NCL and to verify its molecular genetic basis. Four unrelated client owned Chihuahuas from Japan, Italy and England that exhibited progressive neurological signs consistent with a diagnosis of NCL underwent neurological examinations. Brain and in some cases also retinal and heart tissues were examined postmortem for the presence of lysosomal storage bodies characteristic of NCL. The affected dogs exhibited massive accumulation of autofluorescent lysosomal storage bodies in the brain, retina and heart accompanied by brain atrophy and retinal degeneration. The dogs were screened for known canine NCL mutations previously reported in a variety of dog breeds. All 4 dogs were homozygous for the MFSD8 single base pair deletion (MFSD8:c.843delT) previously associated with NCL in a Chinese Crested dog and in 2 affected littermate Chihuahuas from Scotland. The dogs were all homozygous for the normal alleles at the other genetic loci known to cause different forms of canine NCL. The MFSD8:c.843delT mutation was not present in 57 Chihuahuas that were either clinically normal or suffered from unrelated diseases or in 1761 unaffected dogs representing 186 other breeds. Based on these data it is almost certain that the MFSD8:c.843delT mutation is the cause of NCL in Chihuahuas. Because the disorder occurred in widely separated geographic locations or in unrelated dogs from the same country, it is likely that the mutant allele is widespread among Chihuahuas. Genetic testing for this mutation in other Chihuahuas is therefore likely to identify intact dogs with the mutant allele that could be used to establish a research colony that could be used to test potential therapeutic interventions for the corresponding human disease.

GaN and GaxIn1-xN Nanoparticles with Tunable Indium Content: Synthesis and Characterization.

Semiconducting GaN and GaxIn1-xN nanoparticles (4-10 nm in diameter, depending on the metal ratio) with tunable indium content are prepared through a chemical synthesis (the urea-glass route). The bandgap of the ternary system depends on its composition, and therefore, the color of the final material can be turned from bright yellow (the color of pure GaN) to blue (the color of pure InN). Transmission electron microscopy (TEM and HRTEM) and scanning electron microscopy (SEM) images confirm the nanoparticle character and homogeneity of the as-prepared samples. X-ray diffraction (XRD), electron diffraction (EDX), elemental mapping, and UV/Vis, IR, and Raman spectroscopy investigations are used to confirm the incorporation of indium into the crystal structure of GaN. These nanoparticles, possessing adjusted optical properties, are expected to have potential applications in the fabrication of novel optoelectronic devices.

Easy access to Ni3N- and Ni-carbon nanocomposite catalysts.

In the search for alternative materials to current expensive catalysts, Ni has been addressed as one of the most promising and, on this trail, its corresponding nitride. However, nickel nitride is a thermally unstable compound, and therefore not easy to prepare especially as nanoparticles. In the present work, a sol-gel-based process (the urea glass route) is applied to prepare well-defined and homogeneous Ni3N and Ni nanoparticles. In both cases, the prepared crystalline nanoparticles (∼25 nm) are dispersed in a carbon matrix forming interesting Ni3N- and Ni-based composites. These nanocomposites were characterised by means of several techniques, such as XRD, HR-TEM, EELS, and the reaction mechanism was investigated by TGA and IR and herein discussed. The catalytic activity of Ni3N is investigated for the first time, to the best of our knowledge, for hydrogenation reactions involving H2, and here compared to the one of Ni. Both materials show good catalytic activities but, interestingly, give a different selectivity between different functional groups (namely, nitro, alkene and nitrile groups).

Titanium nitride-nickel nanocomposite as heterogeneous catalyst for the hydrogenolysis of aryl ethers.

Lignin from biomass can become a sustainable source of aromatic compounds. Its depolymerization can be accomplished through hydrogenolysis, although the development of catalysts based on cheap and abundant metals is lacking. Herein, a sustainable composite based on titanium nitride and nickel is synthesized and employed as catalyst for the hydrogenolysis of aryl ethers as models for lignin. The catalytic activity of the new material during hydrogenation reactions is proven to be superior to that of either component alone. In particular, different aryl ethers could be efficiently converted under relatively mild conditions into aromatic compounds and cycloalkanes within minutes.

A facile molten-salt route to graphene synthesis.

Efficient synthetic routes are continuously pursued for graphene in order to implement its applications in different areas. However, direct conversion of simple monomers to graphene through polymerization in a scalable manner remains a major challenge for chemists. Herein, a molten-salt (MS) route for the synthesis of carbon nanostructures and graphene by controlled carbonization of glucose in molten metal chloride is reported. In this process, carbohydrate undergoes polymerization in the presence of strongly interacting ionic species, which leads to nanoporous carbon with amorphous nature and adjustable pore size. At a low precursor concentration, the process converts the sugar molecules (glucose) to rather pure few-layer graphenes. The MS-derived graphenes are strongly hydrophobic and exhibit remarkable selectivity and capacity for absorption of organics. The methodology described may open up a new avenue towards the synthesis and manipulation of carbon materials in liquid media.

Synthesis of highly stable, water-dispersible copper nanoparticles as catalysts for nitrobenzene reduction.

We report an aqueous-phase synthetic route to copper nanoparticles (CuNPs) using a copper-surfactant complex and tests of their catalytic efficiency for a simple nitrophenol reduction reaction under atmospheric conditions. Highly stable, water-dispersed CuNPs were obtained with the aid of polyacrylic acid (PAA), but not with other dispersants like surfactants or polymethacrylic acid (PMAA). The diameter of the CuNPs could be controlled in the range of approximately 30-85 nm by modifying the ratio of the metal precursor to PAA. The catalytic reduction of p-nitrophenol to p-aminophenol takes place at the surface of CuNPs at room temperature and was accurately monitored by UV/Vis spectroscopy. The catalytic efficiency was found to be remarkably high for these PAA-capped CuNPs, given the fact that at the same time PAA is efficiently preventing their oxidation as well. The activity was found to increase as the size of the CuNPs decreased. It can therefore be concluded that the synthesized CuNPs are catalytically highly efficient in spite of the presence of a protective PAA coating, which provides them with a long shelf life and thereby enhances the application potential of these CuNPs.

Sponge-like nickel and nickel nitride structures for catalytic applications.

A safe and simple method to fabricate air-stable nickel nitride and nickel embedded in carbon and nitrogen matrix, with high surface area for catalytic applications, is presented. The new synthesis employs molten inorganic salts as the reaction media. The use of salt melt opens new possibilities for safe, simple, and cheap synthesis of metal nitrides and metals for energy-related applications.

Microwave-assisted synthesis of small Ru nanoparticles and their role in degradation of congo red.

Polyethyleneglycol (PEG) stabilized Ru nanoparticles (NPs) were synthesized by single pot rapid microwave (µW) method in presence of glucose as reducing agent. The µW reaction for different amounts of added glucose and PEG was monitored by UV-vis spectroscopy. Small sized NPs (2-5 nm) were obtained with appropriate amounts of glucose and PEG. The size of particles decreased with increasing µW power and decreasing irradiation time (keeping input energy constant), as observed by dynamic light scattering and transmission electron microscopy, which means one has size control via preparation process. X-ray diffraction pattern confirmed hcp lattice of synthesized Ru(0) NPs. To demonstrate their usefulness, a model reaction was selected in which degradation of azo bonds of congo red dye was catalyzed by Ru NPs. This is first report where Ru NPs were employed in catalytic decolorization of an azo dye, which is an important application in waste water treatment. It was found that the NPs acted as an electron mediator in transfer of electron from reducing agent to azo bond. Rate of the reaction increased drastically by introducing Ru NPs in the system and decolorization of dye was accelerated by factor of 200, which is substantial improvement in facilitating this important reaction.

Bottom-up synthesis of Zn(1.7)GeN(1.8)O nanoparticles for photocatalytic application.

Via a simple bottom-up approach, a complex quaternary oxynitride system (Zn1.7GeN1.8O) was prepared in the form of small nanoparticles (d~ 15 nm), which were stable and morphologically well-defined. The Zn1.7GeN1.8O nanoparticles exhibited a band gap of 2.4 eV and were active towards photocatalytic degradation of organic dyes.