Production of Lipid Microparticles Magnetically Active by a Supercritical Fluid-Based Process

An original technique, based on supercriticalCO2and on the particles from gas saturated solution (PGSS) micronization method, was developed to obtain magnetically active lipid microparticles. Magnetite nanoparticles (MNPs) were encapsulated into triestearin and phosphatidylcholine mixtures to increase their biocompatibility for future applications in the fields of biomedical diagnostics and therapeutic medications. The lipid particles produced were characterized to determine size and size distribution, and to confirm the encapsulation of MNP. The mean size was in the range of 200–800 nm. The possibility to drive these magnetically active particles by an external magnet was demonstrated in a simple apparatus simulating a vessel of the circulatory system. The results obtained indicate that the modified PGSS technique is suitable to produce lipid microparticles with magnetic activity for possible use in medical applications

METHOD AND PLANT FOR ACTIVATING CATALYSTS

La presente invenzione si riferisce ad un metodo di attivazione di un materiale catalizzatore solido, ad un catalizzatore attivato ottenibile da detto metodo di attivazione, ad una cella a combustibile, un elettrolizzatore, una batteria metallo-aria o una marmitta catalitica contenente detto catalizzatore attivato, nonché ad un impianto per realizzare detto metodo di attivazione

Production of Lipid Microparticles Magnetically Active by a Supercritical Fluid-Based Process

An original technique, based on supercritical CO2 and on the particles from gas saturated solution (PGSS) micronization method, was developed to obtain magnetically active lipid microparticles. Magnetite nanoparticles (MNPs) were encapsulated into triestearin and phosphatidylcholine mixtures to increase their biocompatibility for future applications in the fields of biomedical diagnostics and therapeutic medications. The lipid particles produced were characterized to determine size and size distribution, and to confirm the encapsulation of MNP. The mean size was in the range of 200–800 nm. The possibility to drive these magnetically active particles by an external magnet was demonstrated in a simple apparatus simulating a vessel of the circulatory system. The results obtained indicate that the modified PGSS technique is suitable to produce lipid microparticles with magnetic activity for possible use in medical applications

Conductivity and Dielectric Relaxations in New Morpholinium- and Piperidinium-Based Ionic Liquids

Room Temperature Ionic Liquids (RTILs) are key materials for the development of new energy storage and conversion systems [1]. In the past decade several relevant properties such as their negligible vapour pressure, non-flammability, and high roomtemperature conductivity were explored in order to obtain safer and better performing devices [2]. Despite of this, the complex interplay existing between the IL nanostructure and the conductivity mechanism is still under discussion within the scientific community [3]. Following this, the synthesis of new ILs and the investigation of their electrical properties are of crucial importance and could pave the way to new applications in the field of ion-conducting materials [4, 5]. This contribution summarizes the electrical study of a family of ILs based on 1-methylmorpholinium (MM+) and 1-methylpiperidinium (MP+) cations. The MM+ and MP+ cations have been synthesized comprising two different alkyl side chain substituents on the nitrogen atom, namely 1-methoxyethyl (ME) and 1-ethoxyethyl (EE) groups. A set of four cations (ME-MM+, EE-MM+, ME-MP+ and EEMP+) neutralized by TFSI-anions is obtained, thus giving rise to four new RTILs. The structure of these ILs allows the systematic investigation of the presence of oxygen atoms on the aliphatic ring (see morpholinium vs. piperidinium cations) with respect to the different substituent side chain length (see methoxyethyl vs.ethoxyethyl groups). The effect of the oxygen atom position on the diffusion of conformational states as well as the charge transfer mechanism is particularly interesting for future Lithium battery applications in which the oxygen atoms are expected to play a crucial role on the migration of Li cations. At this regard, Broadband Electrical Spectroscopy (BES) measurements were undertaken to elucidate the electrical response of the ILs in terms of dielectric relaxations and polarization phenomena. At TTg, interdomain polarization events are detected. These polarization events are associated with the presence of cation and anion nanocluster aggregates with different permittivities. The results allow us to correlate the dielectric relaxations of the different cations with the overall long-range charge migration, thus elucidating the interplay existing between conductivity and nanostructure of this new ILs. References [1] H. Ohno, ed., Electrochemical Aspects of Ionic Liquids, 2nd ed., John Wiley & Sons, Hoboken, NJ, USA, 2005. [2] F. Bertasi, C. Hettige, F. Sepehr, X. Bogle, G. Pagot, K. Vezzù, et al., A Key concept in Magnesium Secondary Battery Electrolytes., ChemSusChem. 8 (2015) 3069–76. [3] A. Tsurumaki, F. Bertasi, K. Vezzù, E. Negro, V. Di Noto, H. Ohno, Dielectric relaxations of polyether-based polyurethanes containing ionic liquids as antistatic agents., PCCP. 18 (2016) 2369–78. [4] F. Bertasi, F. Sepehr, G. Pagot, S.J. Paddison, V. Di Noto, Toward a Magnesium-Iodine Battery, Adv. Funct. Mater. 26 (2016) 4860–4865. [5] M. A. Navarra, K. Fujimura, M. Sgambetterra, S. Panero, A. Tsurumaki, N. Nakamura, H. Ohno, B. Scrosati, New morpholinium- and piperidinium-based ionic liquids, functionalized with ethoxyethyl-side chains, as electrolyte components in lithium and lithium-ion batteries, ChemSusChem. 2017, in press, doi: 10.1002/cssc.201700346

Nanocomposite membranes based on polybenzimidazole and ZrO2 for high-temperature proton exchange membrane fuel cells

Owing to the numerous benefits obtained when operating proton exchange membrane fuel cells at elevated temperature (>100 °C), the development of thermally stable proton exchange membranes that demonstrate conductivity under anhydrous conditions remains a significant goal for fuel cell technology. This paper presents composite membranes consisting of poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI4N) impregnated with a ZrO2 nanofiller of varying content (ranging from 0 to 22 wt %). The structure-property relationships of the acid-doped and undoped composite membranes have been studied using thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, wide-angle X-ray scattering, infrared spectroscopy, and broadband electrical spectroscopy. Results indicate that the level of nanofiller has a significant effect on the membrane properties. From 0 to 8 wt %, the acid uptake as well as the thermal and mechanical properties of the membrane increase. As the nanofiller level is increased from 8 to 22 wt % the opposite effect is observed. At 185 °C, the ionic conductivity of [PBI4N(ZrO2 )0.231 ](H3 PO4 )13 is found to be 1.04×10(-1)  S cm(-1) . This renders membranes of this type promising candidates for use in high-temperature proton exchange membrane fuel cells

Quantum view of Li-ion high mobility at carbon-coated cathode interfaces

Summary: Lithium-ion batteries (LIBs) are among the most promising power sources for electric vehicles, portable electronics and smart grids. In LIBs, the cathode is a major bottleneck, with a particular reference to its low electrical conductivity and Li-ion diffusivity. The coating with carbon layers is generally employed to enhance the electrical conductivity and to protect the active material from degradation during operation. Here, we demonstrate that this layer has a primary role in the lithium diffusivity into the cathode nanoparticles. Positron is a useful quantum probe at the electroactive materials/carbon interface to sense the mobility of Li-ion. Broadband electrical spectroscopy demonstrates that only a small number of Li-ions are moving, and that their diffusion strongly depends on the type of carbon additive. Positron annihilation and broadband electrical spectroscopies are crucial complementary tools to investigate the electronic effect of the carbon phase on the cathode performance and Li-ion dynamics in electroactive materials

Properties of anion exchange membrane based on polyamine: Effect of functionalized silica particles prepared by sol–gel method

Membranes of polyamine (PA-SiNH2)m, containing silica reacted with 3-aminopropyltriethoxysilane (APTES) in hydrolytic conditions were prepared via solution casting, followed by methylation and ion exchange process. The influence of amino-functionalized silica (Si-NH2) on the properties of the obtained membrane was investigated. Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance spectroscopy (NMR) were used to investigate the chemical features of the silica and its interaction with the polyamine polymer. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of the modified membrane confirmed it is stable up to 300 °C. The thermal stability is the result of the interaction of modified silica particles and polyamine polymer. It was demonstrated that the performance of the (PA-SiNH2)m anion exchange membrane is greatly improved by incorporation of silica nanoparticles as compared with the anion exchange membrane (PK-PDAPm), which doesn't contain silica. Therefore, the (PA-SiNH2)m is a suitable candidate for electrochemical applications

Graphene-based \u201ccore-shell\u201d hierarchical nanostructured low-pt electrocatalysts for proton exchange membrane fuel cells

The operation of proton exchange fuel cells (PEMFCs) is bottlenecked by the sluggishness of the oxygen reduction reaction (ORR) [1]. Accordingly, the development of advanced electrocatalysts (ECs) capable to promote the ORR kinetics is one of the main goals of the research. It is further highlighted that, as of today, the only ORR ECs capable to provide PEMFCs with a performance level compatible with applications require a high loading of strategic elements such as platinum-group metals (PGMs), raising critical issues associated with supply shortages and high costs [1]. This work addresses the above points by the development of innovative ECs characterized by the following features: (i) a low loading of PGMs; (ii) an improved ORR activity in comparison with conventional state-of-the-art ECs [2]; (iii) a “core-shell” morphology. In the proposed ECs the “core” support exhibits a hierarchical structure including the following constituents: (i) graphene flakes, to exploit the benefits associated with the large specific surface area and high electron mobility of graphene [3-6]; (ii) carbon black nanoparticles, to further promote the mass and charge transfer processes of the ECs; and (iii) copper nanoparticles, which are introduced as a sacrificial component modulating the EC morphology and the chemical composition of ORR active sites. The hierarchical “core” support is covered by a carbon nitride “shell”, providing “coordination nests” that embed the ORR active sites [7]. The latter are based on a very low loading of Pt (ca. 3 wt% of the EC) and also include Ni and Cu as “co-catalysts”. The proposed L-PGM ECs are obtained customizing the synthetic protocol devised in our research group [7]. In this work, the final ECs are obtained after a post-synthesis activation process carried out by electrochemical cycling, that plays a crucial role to modulate the physicochemical properties and the morphology. Preliminary results indicate that the proposed approach is promising, as the proposed L-PGM ECs exhibit an improved specific and mass activity in comparison with the state of the art (see Figure). The assay of the metals in the L-PGM ECs is evaluated by inductively-coupled plasma atomic emission spectroscopy (ICPAES). Vibrational spectroscopies (e.g., confocal micro-Raman) and wide-angle X-ray diffraction (WAXD) are adopted to probe the structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), both conventional and at high resolution, are used to study the morphology. Cyclic voltammetry with the rotating ring-disk electrode method (CV-TFRRDE) investigates the electrochemical performance and ORR reaction mechanism. Finally, the fuel cell performance in operating conditions is tested on PEMFC prototypes including the proposed L-PGM ECs at the cathode. Acknowledgements This work was funded by the Strategic Project of the University of Padova “From Materials for Membrane-Electrode Assemblies to Energy Conversion and Storage Devices – MAESTRA”. The research leading to these results has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement n°696656. REFERENCES [1] I. Katsounaros, S. Cherevko, A. R. Zeradjanin, K. J. J. Mayrhofer, Angew. Chem. Int. Ed., 53, 102 (2014). [2] J. Zhang, Front. Energy, 5, 137 (2011). [3] S. Sharma, B. G. Pollet, J. Power Sources, 208, 96 (2012). [4] M. Liu, R. Zhang, W. Chen, Chem. Rev., 114, 5117 (2014). [5] A. C. Ferrari, F. Bonaccorso, V. Fal’ko et al., Nanoscale, 7, 4587 (2015). [6] J. H. Chen, C. Jang, S. Xiao, M. Ishigami, M. S. Fuhrer, Nature Nanotech., 3, 206 (2008). [7] V. Di Noto, E. Negro, K. Vezzù, F. Bertasi, G. Nawn, The Electrochemical Society Interface, Summer 2015, 59 (2015)

Hierarchical graphene-supported PtNix, AuNix and FeSnx “core-shell” carbon nitride electrocatalysts for the oxygen reduction reaction

The sluggish kinetics of the oxygen reduction reaction (ORR) is one of the main drawbacks towards the commercialization of proton exchange membrane fuel cells (PEMFCs) and anion exchange membrane fuel cells (AEMFCs). State-of-the-art ORR electrocatalysts (ECs) consist of carbon-supported Pt nanoparticles. Nonetheless, the insufficient durability of these ECs and the low abundance of platinum constitute some of the major challenges for large-scale commercialization of PEMFC and AEMFC technology [1]. Thus, the development of very efficient cathodic electrocatalysts is necessary to substitute the Pt/C “state-of-the-art” ECs. In this work a group of hierarchical “core-shell” ECs for the ORR is synthesized following an innovative preparation protocol [2]. The “shell” consists of a carbon nitride (CN) matrix coordinating bimetallic PtNix, AuNix and FeSnx nanoparticles. The “core” consist of graphene nanoplatelets [3]. Inductively-coupled plasma atomic emission spectroscopy (ICP-AES) and microanalysis are carried out to evaluate the chemical composition of the ECs; Scanning Electron Microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) are used for the inspection of the morphology; powder X-ray diffraction (XRD) is adopted to study the structure of the ECs. Cyclic voltammetry with the thin-film rotating ring-disk electrode (CV-TF-RRDE) is used to determine the ORR performance and to study the reaction mechanism. The analysis of the chemical composition of the ECs reveals that N functionalities are bonded in the CN “shell” matrix covering the “cores” of graphene nanoplatelets. An increase of the pyrolysis temperature from 600 to 900°C improves the graphitization degree of the CN “shell” and facilitates the alloying process of the bimetallic metal nanoparticles of the ECs. Accordingly, ohmic drops of materials are reduced and the ORR activity is significantly improved. References [1] R. Othman, A. L. Dicks, Z. Zhu, Int. J. Hydrogen Energy, 37 (2012) 357-372. [2] V. Di Noto, E. Negro, F. Bertasi et al., Patent application 102015000055603. [3] V. Di Noto, E. Negro, S. Polizzi et al., ChemSusChem., 5 (2012) 2451–2459