Performance study on the addition of novel functionalized graphene oxide in activated carbon-based electrodes for capacitive deionization

Graphene oxide (GO) and its reduced and functionalized forms have been attracting the interest of the scientific community. Widely studied for its unique properties, GO finds applications in the vast and heterogenous scenario of various research fields. When focusing on porous electrodes for capacitive applications, GO is commonly proposed in its reduced form (rGO) for improved electrical conductivity. Specifically, designed functionalization procedures are also used to tune the charges spontaneously present on the surface of GO. In this context, this work reports on the investigation of few novel functionalized GO materials proposed for capacitive deionization application. The modification of the GO has been pursued following different strategies in order to achieve a controlled tuning of the surface charge of the GO. The functionalized materials have been widely characterized by means of morphological, physico-chemical and electrochemical characterization techniques. Finally, the materials have been mixed with activated carbons and coated onto metallic current collectors to assemble a device for capacitive deionization application. Performances of the different materials have been compared in terms of salt adsorption and charge efficiency, proving the beneficial effect of the presence of functionalized GO. Interestingly, the same approach and materials can also be applied for the case of aqueous supercapacitors, since they share many features and similar working mechanism with capacitive deionization

Performance study on the addition of novel functionalized graphene oxide in activated carbon-based electrodes for capacitive deionization

Graphene oxide (GO) and its reduced and functionalized forms have been attracting the interest of the scientific community. Widely studied for its unique properties, GO finds applications in the vast and heterogenous scenario of various research fields. When focusing on porous electrodes for capacitive applications, GO is commonly proposed in its reduced form (rGO) for improved electrical conductivity. Specifically, designed functionalization procedures are also used to tune the charges spontaneously present on the surface of GO. In this context, this work reports on the investigation of few novel functionalized GO materials proposed for capacitive deionization application. The modification of the GO has been pursued following different strategies in order to achieve a controlled tuning of the surface charge of the GO. The functionalized materials have been widely characterized by means of morphological, physico-chemical and electrochemical characterization techniques. Finally, the materials have been mixed with activated carbons and coated onto metallic current collectors to assemble a device for capacitive deionization application. Performances of the different materials have been compared in terms of salt adsorption and charge efficiency, proving the beneficial effect of the presence of functionalized GO. Interestingly, the same approach and materials can also be applied for the case of aqueous supercapacitors, since they share many features and similar working mechanism with capacitive deionization

Microwave-assisted synthesis of N/S-doped CNC/SnO2 nanocomposite as a promising catalyst for oxygen reduction in alkaline media

In this study, we report an all-green approach for the synthesis of novel catalysts for oxygen reduction reaction (ORR) via a simple two-step procedure. In particular, conductive cellulose nanocrystals (CNCs) were obtained via pyrolysis, and a successive microwave-assisted hydrothermal process was employed to activate the carbon lattice by introducing sulfur (S) and nitrogen (N) dopants, and to decorate the surface with tin oxide (SnO2) nanocrystals. The successful synthesis of N/S-doped CNC/SnO2 nanocomposite was confirmed by X-ray Photoelectron Spectroscopy analysis, Energy Dispersive X-ray microanalysis, X-ray Diffraction and Field Emission Scanning Electron Microscopy. The synergistic effects of the dopants and SnO2 nanocrystals in modifying the catalytic performance were proved by various electrochemical characterizations. Particularly, the nanocomposite material reaches remarkable catalytic performance towards the ORR, close to the Pt/C benchmark, in alkaline environviment, showing promising potential to be implemented in alkaline fuel cell and metal-air battery applications

Tin sulfide supported on cellulose nanocrystals-derived carbon as a green and effective catalyst for CO2 electroreduction to formate

This work reports a whole green two-step approach for the synthesis of novel catalysts for efficient CO2 conversion. A conductive carbon support was firstly obtained via pyrolysis of cellulose nanocrystals (CNCs), and the carbon surface was successively decorated with tin sulfide (SnS) through a microwave-assisted hydrothermal process. The morphology and carbon structure were characterized by field emission scanning electron microscopy and Raman spectroscopy, and the presence of SnS decoration was confirmed by X-ray photoelectron spectroscopy and X-ray diffraction analyses. The SnS supported on CNC-derived carbon shows enhanced catalytic activity for the CO2 conversion to formate (HCOO-). Good selectivity of 86% and high partial current density of 55 mA cm(-2) are reached at - 1.0 V vs. reversible hydrogen electrode in KHCO3 electrolyte. Additionally, the mass activity of the composite catalyst achieves a value as high as 262.9 mA mgSn(-1) for HCOO- formation, demonstrating good utilization efficiency of Sn metal. In this work, the low-cost CNC-derived carbon is evidenced to be easily decorated with metal species and thus shows high versatility and tailorability. Incorporating metal species with conductive high-surface carbon supports represents an effective strategy to realize active and stable electrocatalysts, allowing efficient utilization of metals especially the raw and precious ones

Facile Chemical Synthesis of Doped ZnO Nanocrystals Exploiting Oleic Acid

Zinc oxide nanocrystals (ZnO-NCs) doped with transition metal elements or rare earth elements can be probed for magnetic resonance imaging to be used as a molecular imaging technique for accurate diagnosis of various diseases. Herein, we use Mn as a candidate of transition metal elements and Gd as a presenter of rare earth elements. We report an easy and fast coprecipitation method exploiting oleic acid to synthesize spherical-shaped, small-sized doped ZnO-NCs. We show the improved colloidal stability of oleate-stabilized doped ZnO-NCs compared to the doped ZnO-NCs synthesized by conventional sol-gel synthesis method, i.e., without a stabilizing agent, especially for the Mn dopant. We also analyze their structural, morphological, optical, and magnetic properties. We are able to characterize the persistence of the crystalline properties (wurtzite structure) of ZnO in the doped structure and exclude the formation of undesired oxides by doping elements. Importantly, we determine the room-temperature ferromagnetism of the doped ZnO-NCs. This oleate-stabilized coprecipitation method can be subjected as a standard procedure to synthesize doped and also co-doped ZnO-NCs with any transition metal elements or rare earth elements. In the future, oleate-stabilized Gd/Mn-doped ZnO-NCs can be exploited as magnetic resonance imaging (MRI) contrast agents and possibly increase the signal intensity on T1-weighted images or reduce the signal intensity on T2-weighted images

Antimicrobial resistance in marine mammals of the Uruguayan coast : Preliminary results

In this work, isolations, identification and determination of antimicrobial resistance of strains of Enterobacteriaceae isolated from necropsy samples of a juvenile sea lion (Otaria flavescens) from the Isla de Lobos, Uruguay were carried out. The study samples were taken using swabs from the larynx, esophagus, trachea, duodenum and bladder, which were first seeded in Tryptic Soy Agar (TSA) and then in selective and differential culture media for Enterobacteriaceae (Xylose Lysine Deoxycholate and Mac Conkey). After the phenotypic identification of the isolates by biochemical tests, their identity was confirmed by amplifying and sequencing a fragment of the gene that codes for 16S rRNA.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

BIOMIMETIC NON - IMMUNOGENIC NANOASSEMBLY FOR THE ANTITUMOR THERAPY

Nanoassembly ( 1 ) for inducing apoptosis in cancer cells comprising : a core ( 2 ) comprising at least a nanoparticle of a nano structured and semiconductor metal oxide , said nanoparticle being monocrystalline or polycrystalline ; a shell ( 3 ) formed by a double phospholipid layer and proteins derived from an extracellular biovesicole chosen between an exosome , an ectosome , a connectosome , an oncosome and an apoptotic body , and an oncosome , said core ( 2 ) being enclosed inside said shell ( 3 ) ; and a plurality of targeting molecules ( 4 , 4 ' , 4 " ) of said cancer cells , preferably mono clonal antibodies ( 4 , 4 ' , 4 " ) , said molecules ( 4 , 4 , 4 " ) being anchored to the external surface of said biovesicole

Reduced Graphene Oxide Embedded with ZnS Nanoparticles as Catalytic Cathodic Material for Li-S Batteries

Lithium-sulfur technology is a strong candidate for the future generation of batteries due to its high specific capacity (1675 mAh g−1), low cost, and environmental impact. In this work, we propose a facile and solvent-free microwave synthesis for a composite material based on doped (sulfur and nitrogen) reduced graphene oxide embedded with zinc sulfide nanoparticles (SN-rGO/ZnS) to improve the battery performance. The chemical-physical characterization (XRD, XPS, FESEM, TGA) confirmed the effectiveness of the microwave approach in synthesizing the composite materials and their ability to be loaded with sulfur. The materials were then thoroughly characterized from an electrochemical point of view (cyclic voltammetry, galvanostatic cycling, Tafel plot, electrochemical impedance spectroscopy, and Li2S deposition test); the SN-rGO/ZnS/S8 cathode showed a strong affinity towards polysulfides, thus reducing their loss by diffusion and improving redox kinetics, allowing for faster LiPSs conversion. In terms of performance, the composite-based cathode increased the specific capacity at high rate (1 C) from 517 to 648 mAh g−1. At the same time, more stable behavior was observed at 0.5 C with capacity retention at the 750th cycle, where it was raised from 32.5% to 48.2%, thus confirming the beneficial effect of the heteroatomic doping process and the presence of zinc sulfide nanoparticles