Cerium Nitrate Hexahydrate Research Articles

The antimicrobial efficacy of biosynthesized nanostructured ceria

Biosynthesis of metal oxide nanoparticles is an emerging eco-friendly approach. Currently, researchers have been developing various nanomaterials with effective antimicrobial properties with less toxicity to humans. Here, nanostructured ceria or cerium oxide nanoparticles of average crystallite size ∼5 nm are synthesized by a chemical co-precipitation method using cerium nitrate hexa hydrate and sodium hydroxide as starting materials. The most fascinating bio-material known to man, deoxyribo nucleic acid (DNA) is used as a biological capping agent to get well dispersed nanoparticles. The structural and morphological characterization of prepared samples was conducted using X-ray diffraction, high resolution transmission electron microscopy and Fourier transform infrared spectroscopy. The synthesized cerium oxide nanoparticle showed potential antibacterial activity against both bacteria and fungi under investigation. The results also showed that the synthesized nanoceria can be used to inhibit the growth of several fungi which will be useful for a number of applications in the biomedical field.

Sonochemical synthesis of CeVO4 nanoparticles for electrochemical hydrogen storage

In this study, the synthesis of cerium vanadate (CeVO4) nanoparticles using ammonium metavanadate, cerium (III) nitrate hexahydrate as the primary reactant and hydrazine as the source of OH− was presented in the absence and presence of ultrasonic waves. Reaction control was performed using OH− and ethylenediamine sources. Other parameters such as solvent, surfactant, power, and time were also examined. Nanostructures were analyzed by XRD, FESEM, FTIR, DLS, BET, and EDS. FESEM results showed that using ultrasonic irradiation, relatively fine spherical nanoparticles were formed in one step while uniform spherical nanostructures were formed in a two-step path. The obtained product was used for electrochemical storage of hydrogen. The discharge capacity of spherical nanoparticles of CeVO4 with high uniformity was recorded at about 4299 mAh/g.

CeO2 quantum dots anchored g-C3N4: synthesis, characterization and photocatalytic performance

Cerium dioxide quantum dots (CeO2QDs) modified graphitic carbon nitride (g-C3N4) was fabricated by a facile chemical reaction with urea and cerium nitrate hexahydrate as precursors. Combined X-ray diffraction (XRD), UV–Vis DRS, transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), Electrochemical impedance spectra (EIS), Thermogravimetric analysis (TGA), Brunner-Emmet-Teller (BET) measurements and X-ray photoelectron spectroscopy (XPS) studies showing that CeO2QDs dispersed homogeneously on the g-C3N4 surface, which enhanced the absorption in visible light region. Specifically, we found that CeO2QDs/g-C3N4 shows much lower electron-hole recombination rate, and its Rhodamine B photodegradation rate constant can reach 0.00985 min−1, which is 7 times higher than that of single g-C3N4. In addition, the CeO2QDs/g-C3N4 displayed outstanding catalytic stability. Furthermore, the CeO2QDs/g-C3N4 catalyst also exhibited the excellent photodegradation performance on other substrates such as TC, Methyl Orange, and Methyl Blue. It was proposed that the CeO2QDs/g-C3N4 photocatalyst could follow a more appropriate Z-scheme charge transfer mechanism. Our studies extend the application of Quantum dots nanocomposite catalyst and pave the way for its further rational design.

Organic and inorganic compounds as corrosion inhibitors to reduce galvanic effect for the hybrid structure AA2024-CFPR

The effect of the galvanic corrosion process taking place between aluminium alloy (AA2024-T3) and carbon fiber reinforced plastic (CFRP) immersed in 0.05 M NaCl was studied using organic and inorganic compounds as corrosion inhibitors. Electrochemical approaches such as electrochemical noise analysis (ENA) and electrochemical impedance spectroscopy (EIS) were carried out to evaluate efficiencies of 1,2,4-triazole (C2H3N3) and cerium nitrate hexahydrate (Ce(NO3)3·6H2O) as corrosion inhibitors. The highest efficiency was reached for Ce(NO3)3.6H2O, with some improvement observed by adding C2H3N3 in a mixed inhibitor solution. The noise resistance (Rn) and polarization resistance (Rp) values calculated from ENA and EIS data showed almost identical behavior with different magni­tudes but similar trends. Adsorption isotherm models estimated with fractional surface coverage (q) parameter were fitted better to Langmuir model for C2H3N3 and Temkin model for Ce(NO3)3·6H2O. The calculated values of Gibbs free energy suggested physi­sorption and chemisorption as spontaneous interactions between a metal surface and both inhibitors. Energy-dispersive X-ray spectroscopy (EDS) was carried out before and after immersing AA2024-T3 in the electrolyte, identifying rich zones in copper with cerium deposited over it and confirming the presence of rare-earth oxide deposition and oxide film products. The EDS analysis for CFRP revealed the deposition of Ce and Al particles over its surface after immersion in the electrolyte, especially in the areas rich in carbon.

Efficiency of cerium oxide (CeO2) nano-catalyst in degrading the toxic and persistent 4-nitrophenol in aqueous solution

Cerium oxide (CeO2) generally termed as nanoceria is a rare earth metal oxide, that has become an vital key ingredient in many wide range of applications in different fields like gas sensors, ultraviolet absorbents, catalysis, solid oxide fuel cells, glass-polishing materials etc., In this work, Cerium oxide nanoparticles with uniform structure have been prepared by simple Chemical Precipitation method by using Cerium nitrate hexahydrate as the precursor. The synthesized nanoparticles have been characterised by XRD, FT-IR, SEM, EDAX, TEM, XPS etc., The results of the characterization studies revealed the formation of CeO2 nanoparticles. The photocatalytic ability of the synthesized nanoparticles was studied by degrading 4-nitrophenol dye under visible light irradiation.

Microwave rapid fabrication of cerium/cobalt nickel sulfide electrode materials for high performance supercapacitors

In this work, a novel electrode materials of cerium/cobalt nickel sulfide (Ce/CoNi2S4) was synthesized by a one-step microwave approach. The Ce doping effect has been an efficient method to increase the rate properties and specific capacitance of the supercapacitor. When the current density is 1 A g−1, the specific capacitance of the CoNi2S4 electrode is 1988 F g−1, but when a small amount of rare earth (cerium nitrate hexahydrate) was doped, the optimized Ce/CoNi2S4 electrode exhibits a great specific capacitance of 2408 F g−1 at 1 A g−1 and excellent cycling stabilities (86% retention after 10000 cycles and 71% retention after 20000 cycles). In addition, the Ce/CoNi2S4 nanoflower shows excellent performance for aqueous asymmetric supercapacitor, and the energy density is as high as 70.4 Wh kg−1 when the power density is 750 W kg−1, and 52.1 Wh kg−1 when the power density is 7500 W kg−1. The Ce/CoNi2S4 electrode materials were synthesized by household microwave oven, which can not only realize the simple and efficient synthesis of materials, but also can realize the improvement of the properties of sulfide materials. This rare earth doped sulfide is a new concept in the synthesis design, and can also be apply to the synthesis of other materials, which has a certain guiding effect on the improvement of the performance of electrode materials in supercapacitors.

Crystallographic and Spectroscopic Investigations on Oxidative Coordination in the Heteroleptic Mononuclear Complex of Cerium and Benzoxazine Dimer.

Among lanthanide-based compounds, cerium compounds exhibit a significant role in a variety of research fields due to their distinct tetravalency, high economic feasibility, and high stability of Ce(IV) complexes. Herein, a systematic investigation of crystallographic information, chemical properties, and mechanistic formation of the novel Ce(IV) complex synthesized from cerium(III) nitrate hexahydrate and 2,2′-(methylazanediyl)bis(methylene)bis(4-methylphenol) (MMD) ligand has been explored. According to the analysis of the crystallographic information, the obtained complex crystal consists of the Ce(IV) center coordinated with two nitrate ligands and two bidentate coordinated (N-protonated and O,O-deprotonated) MMD ligands. The fingerprint plots and the Hirshfeld surface analyses suggest that the C–H⋯O and C–H⋯π interactions significantly contribute to the crystal packing. The C–H⋯O and C–H⋯π contacts link the molecules into infinite molecular chains propagating along the [100] and [010] directions. Synchrotron powder X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques have been employed to gain an understanding of the oxidative complexation of Ce(IV)-MMD complex in detail. This finding would provide the possibility to systematically control the synthetic parameters and wisely design the precursor components in order to achieve the desired properties of novel materials for specific applications.

Self-assembly of ionic and non-ionic surfactants in type IV cerium nitrate and urea based deep eutectic solvent.

Understanding and manipulating micelle morphology are key to exploiting surfactants in various applications. Recent studies have shown surfactant self-assembly in a variety of Deep Eutectic Solvents (DESs) where both the nature of surfactants and the interaction of the surfactant molecule with the solvent components influence the size, shape, and morphology of the micelles formed. So far, micelle formation has only been reported in type III DESs, consisting solely of organic species. In this work, we have explored the self-assembly of cationic surfactant dodecyl trimethylammonium nitrate/bromide (C12TANO3/C12TAB), anionic surfactant sodium dodecyl sulfate (SDS), and non-ionic surfactants hexaethylene glycol monododecyl ether (C12EO6) and octaethylene glycol monohexadecyl ether (C16EO8) in a type IV DES comprising metal salt, cerium (III) nitrate hexahydrate, and a hydrogen bond donor, urea, in the molar ratio 1:3.5. C12TANO3, C12TAB, C12EO6, and C16EO8 form spherical micelles in the DES with the micelle size dependent on both the surfactant alkyl chain length and the head group, whereas SDS forms cylindrical micelles. We hypothesize that the difference in the micelle shape can be explained by counterion stabilization of the SDS headgroup by polycations in the DES compared to the nitrate/bromide anion interaction in the case of cationic surfactants or molecular interaction of the urea and the salting out effect of (CeNO3)3 in the DES on the alkyl chains/polyethoxy headgroup for non-ionic surfactants. These studies deepen our understanding of amphiphile self-assembly in this novel, ionic, and hydrogen-bonding solvent, raising the opportunity to use these structures as liquid crystalline templates to generate porosity in metal oxides (ceria) that can be synthesized using these DESs.

The Effect of Precursor Concentration on the Particle Size, Crystal Size, and Optical Energy Gap of CexSn1-xO2 Nanofabrication.

In the present work, a thermal treatment technique is applied for the synthesis of CexSn1−xO2 nanoparticles. Using this method has developed understanding of how lower and higher precursor values affect the morphology, structure, and optical properties of CexSn1−xO2 nanoparticles. CexSn1−xO2 nanoparticle synthesis involves a reaction between cerium and tin sources, namely, cerium nitrate hexahydrate and tin (II) chloride dihydrate, respectively, and the capping agent, polyvinylpyrrolidone (PVP). The findings indicate that lower x values yield smaller particle size with a higher energy band gap, while higher x values yield a larger particle size with a smaller energy band gap. Thus, products with lower x values may be suitable for antibacterial activity applications as smaller particles can diffuse through the cell wall faster, while products with higher x values may be suitable for solar cell energy applications as more electrons can be generated at larger particle sizes. The synthesized samples were profiled via a number of methods, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). As revealed by the XRD pattern analysis, the CexSn1−xO2 nanoparticles formed after calcination reflect the cubic fluorite structure and cassiterite-type tetragonal structure of CexSn1−xO2 nanoparticles. Meanwhile, using FT-IR analysis, Ce-O and Sn-O were confirmed as the primary bonds of ready CexSn1−xO2 nanoparticle samples, whilst TEM analysis highlighted that the average particle size was in the range 6−21 nm as the precursor concentration (Ce(NO3)3·6H2O) increased from 0.00 to 1.00. Moreover, the diffuse UV-visible reflectance spectra used to determine the optical band gap based on the Kubelka–Munk equation showed that an increase in x value has caused a decrease in the energy band gap and vice versa.

Sunlight-assisted synthesis of cerium (IV) oxide nanostructure with enhanced photocatalytic activity

In this work, cerium oxide (CeO2) nanostructures have been synthesized using a sunlight-assisted combustion method from cerium nitrate hexahydrate and glycine as precursors. The synthesized sunlight-assisted cerium oxide (CeO2-SA) nanopowder has been characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscope, UV–Visible spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, and Nitrogen adsorption–desorption isotherm. In this method of synthesis, natural sunlight is used as energy source to ignite the reaction and the product is obtained immediately. The synthesized CeO2-SA has a fluorite-like cubic crystal structure and spongy morphology with irregular pores. It is also found that CeO2-SA possesses a smaller particle size, narrower band gap and lower recombination rate than bulk CeO2. The crystalline size of CeO2-SA nanoparticles was obtained to be 4.9 nm. The optical band gap for CeO2-SA was found to be 2.98 eV. The BET Surface area for CeO2-SA was found to be 19.7 m2/g which is 5.3 times greater than the surface area of bulk CeO2 (3.7 m2/g). Around 91% degradation of methylene blue dye (MB) is observed. Therefore, CeO2-SA exhibits higher photocatalytic efficiency towards the degradation of MB than bulk CeO2.

Cerium/Ascorbic Acid/Iodine Active Species for Redox Flow Energy Storage Battery.

In this study, we developed a novel cerium/ascorbic acid/iodine active species to design a redox flow battery (RFB), in which the cerium nitrate hexahydrate [Ce(NO3)3·6H2O] was used as a positive Ce3+/Ce4+ ion pair, and the potassium iodate (KIO3) containing ascorbic acid was used as a negative I2/I− ion pair. In order to improve the electrochemical activity and to avoid cross-contamination of the redox pair ions, the electroless plating and sol–gel method were applied to modify the carbon paper electrode and the Nafion 117 membrane. The electrocatalytic and electrochemical properties of the composite electrode using methanesulfonic acid as a supporting electrolyte were assessed using the cyclic voltammetry (CV) test. The results showed that the Ce (III)/Ce (IV) active species presented a symmetric oxidation/reduction current ratio (1.09) on the C–TiO2–PdO composite electrode. Adding a constant amount of ascorbic acid to the iodine solution led to a good reversible oxidation/reduction reaction. Therefore, a novel Ce/ascorbic acid/I RFB was developed with C–TiO2–PdO composite electrodes and modified Nafion 117–SiO2–SO3H membrane using the staggered-type flow channel, of which the energy efficiency (EE%) can reach about 72%. The Ce/ascorbic acid/I active species can greatly reduce the electrolyte cost compared to the all-vanadium redox flow battery system, and it therefore has greater development potential.

Effect of Cerium Oxide Nanoparticles to Improve the Combustion Characteristics of Palm Oil Nano Water Emulsion using Low Heat Rejection Engine

ABSTRACT Biodiesel plays an important role in the automotive sector due to the enormous demand for conventional fuels such as diesel. A significant drawback of utilizing conventional fuel in the base engine is tailpipe emissions. The addition of water into the fuel reduced the harmful pollutants emitted from the engine and improved engine performance. The palm oil was used as biodiesel and it was mixed with 5% (by volume) water content to the fuel and tween 80 and span 80 is used as a co-surfactant and surfactant. Cerium oxide was used as a nanoparticle and mixed with biodiesel water emulsion in a 30 ppm dosage using an ultrasonicator. The partially stabilized zirconium was used as a coating product, and the desired coating thickness was 500 microns (or 0.5 mm) on the piston head, inlet, and exhaust value using the plasma spray method. The tailpipe emission characteristics of hydrocarbon, carbon monoxide oxides of nitrogen and smoke were decreased by 16.6%, 18.02%, 6.7%, and 29.16% for utilizing blend of palm oil nanoemulsion in the engine when correlated to diesel fuel. The thermal efficiency increased by 14.03% for palm oil nanoemulsion as compared with the neat diesel. Abbreviations: PNAE Palm oil nanoadditive emulsion HLB Hydrophile-lipophile balance PSZ Partially stabilized zirconium WWF World Wildlife Fund PONE Palm oil nanoemulsionPO100Neat palm oil POE Palm oil emulsion BTE Brake thermal efficiency HC Hydrocarbon COCarbon monoxideNO x Oxides of nitrogen HRR Heat release rate LGO Lemongrass oilIDIgnition delay WCO Waste cooking oilI CPIn-cylinder pressureLHVLatent heat of vaporization SOME Sesame oil methyl ester TC Thermal conductivity CNH Cerium nitrate hexahydrate

Influence of Ce2O3 addition on the basicity of Ni/MgO and on its catalytic performance in dry reforming of methane (Turning CO2 to fuel)

The only way to stabilize the Earth’s climate is to stabilize the concentration of greenhousegases in the atmosphere. In this study, the conversion of methane and CO2 to synthesis gasusing dry reforming over catalysts Ni/Mg1-XCeXO (x= 0, 0.03, 0.07, 0.15; 1 wt% Ni each),dry reforming of methane was performed. The catalysts were prepared by K2CO3 coprecipitationfrom aqueous cerium nitrate hexahydrate and magnesium nitrate hexahydrate.Impregnation of nickel (II) acetylacetonate onto MgO-Ce2O3 was then conducted. TEM,XRD, FTIR, XRF, XPS, and BET characterizations of the catalysts were carried out.Results showed that the catalysts were reduced at 700 °C by H2 prior to each reaction. CH4and CO2 conversions at 900 °C of the catalysts after being tested for 200h decreased in theorder Ni/Mg0.85Ce0.15O, Ni/Mg0.93Ce0.07O, Ni/Mg0.97Ce0.03O, and Ni/MgO. The highest H2and CO selectivities, was observed at a 1:1 CH4:CO2 mole ratio. We further performed adry reforming in the presence of low-concentration oxygen flow (1.25 Vol %) and found anincreased CH4 conversion.

Characterization of Gd doped CeO2 thin films grown by ultrasonic spray pyrolysis

Abstract Gd concentration effect on the optical, structural, surface and electrical properties of Gd doped CeO2 thin films are coated on glass substrates by spray pyrolysis technique with precursors containing cerium nitrate hexahydrate [Ce(NO3)3·6H2O] and gadalinium nitrate hexahydrate [Gd(NO3)3·6H2O] as a source material. The structural, morphologicaly and elemental characterizations of the films have been carried out using x-ray diffraction, field emission scanning electron microscopy and energy dispersive x-ray analysis, respectively. An optical energy band gap is calculated in the range 3.3–3.8 eV from UV–Vis transmittance spectra. Surface morphologies and roughness values of the films have been investigated by atomic force microscopy. Thicknesses have been determined using spectroscopic ellipsometry technique and Cauchy–Urbach model. A four-probe setup has been used to determine the electrical resistivity values. All samples showed x-ray diffraction peaks corresponding to a cubic fluorite structure. The results indicate that the deposited films have a preferential growth in the (0 0 2) direction. The observed transmittance in the visible region has been situated between 60% and 70%. Photoluminescence spectra showed an ultraviolet emission band around 365–400 nm and the visible emission peaks between 469 and 590 nm. Raman active peaks for undoped and Gd doped CeO2 films were determined at ~465 cm−1. Finally, it has been concluded that Gd doped CeO2 films have value to work on and may be promising materials for optoelectronic applications.

Synthesis and Characterization of Dimeric Thio-Schiff Bases by Nano Cerium Oxide and Examination of Their Antimicrobial Activities

In this work, firstly, CeO2 nanoparticles, which can be used as catalysts in many reactions, were synthesized by preparing aqueous solution of cerium(III) nitrate hexahydrate in basic medium. In the second step, the synthesis of dimeric thio Schiff bases was carried out using two different methods. Effect of catalyst on some parameters such as reaction time and yield of product were investigated. The antimicrobial activities of the ligands have been screened in vitro against the organisms Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae (Gram negative bacteria), Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Bacillus cereus (Gram positive bacteria) and Candida albicans, C. tropicalis, C. guilliermondii, C. glabrata by Disc Diffusion and Microdilution methods. At the same time, antimicrobial activities of ligands were compared to standard antibiotics (Cefotaxime, Amoxicillin/clavulanic acid, Posacanazole, Nystatin and Gentamicin). Generally, the results obtained in this research showed that all tested ligands exhibited more effect towards Gram positive bacteria and Candida species as compared to standard antibiotics.

Preparation and characterization of submicron-cerium oxide by hypergravity coprecipitation method

Submicron-cerium oxide particles were synthesized by applying hypergravity using ammonium bicarbonate (precipitant) and cerium nitrate hexahydrate (precursor). The influence of the concentration, pH, dispersant loading, flow rate, rotation speed of the hypergravity rotating bed, calcination temperature, and time on the cerium oxide particle size were examined by zeta potential, solid–liquid contact angle, thermo-gravimetry–differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The cerium oxide particles were highly dispersed, with an average particle size of 200 nm. Calcining at 650 °C for 1.5 h afforded the smallest particles. The crystallite size and fraction crystallinity increased with prolonged calcination. Crystalline cerium dioxide grew along three crystal planes, forming a complete face-centered cube, affording high hardness and activity of the polishing powder. The optimal conditions were: cerium nitrate concentration: 0.7 mol/L, cerium nitrate/ammonium bicarbonate molar ratio: 1:3, dispersant mass fraction: 3%, cerium nitrate initial pH: 4–5; the precursor solution was adjusted to pH 9 with ammonia water. Hypergravity coprecipitation with 1.5 h calcination afforded submicron-sized cerium oxide with a uniform size distribution using ammonium bicarbonate in an industrially viable process. The simple and low-cost manufacturing process may enable the development of hypergravity-assisted chemical synthesis technology.

A Simple Nano Cerium Oxide Modified Graphite Electrode for Electrochemical Detection of Formaldehyde in Mushroom

In this present work, electrochemical detection and quantification of formalin (FAL) trace present in mushroom (Agaricus bisporus) was premeditated using a cerium oxide nanoparticle modified graphite paste electrode (CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> @GP). Cerium oxide (CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) nanoparticles (nps) were synthesized through the sol-gel technique from cerium nitrate hexahydrate using poly (ethylene glycol) as a capping agent. The prepared CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nps were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques which revealed the successful formation of the cubic phase of CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> having crystallite size 4.84 nm. The prepared CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nps were used to modify the graphite paste electrode (bare GP). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were utilized to study comparative electroanalytical features of the fabricated electrodes. Under optimized experimental conditions, CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> @GP exhibited a wide linear range from 25 μM-1mM and a limit of detection of 1 μM. Moreover, CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> @GP featured high repeatability, reproducibility, and long-term stability. The electrode exhibited high selectivity for FAL in the presence of interferences like ethanol, methanol, formic acid, benzaldehyde, and acetone. CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> @GP demonstrated exceptional aptitudes in electrochemical behavior when subjected to mushroom extract.

Comprehensive permeation analysis and mechanical resistance of electroless pore-plated Pd-membranes with ordered mesoporous ceria as intermediate layer

H2-selective composite membranes, particularly those based on palladium films deposited onto porous stainless-steel supports, represent a promising technology to be practically included in both independent devices and membrane reactors. To reach thin H2-selective films and hence high permeance values, the use of a wide variety of intermediate layers is usually adopted in the literature. However, an agreement about the best solution is not found up to now. In this context, the current study presents the use of Ordered Mesoporous Ceria (OMC) particles as intermediate layer for the improvement of permeation properties of Electroless Pore-Plated (ELP-PP) Pd-composite membranes. OMC was obtained by nanocasting from SBA-15 as temporary template and cerium nitrate (III) hexahydrate as metal precursor. Resultant OMC particles have around 100 nm spherical diameter, an average pore-size diameter of 10–12 nm, and a total BET surface of around 134 m2/g. This material was next deposited onto the external surface of tubular Porous Stainless-Steel (PSS) supports by vacuum-assisted dip-coating (VA-DC) to form an intermediate layer that makes the preparation of a defect-free and thin Pd-film easier. This procedure allows the preparation of Pd composite membranes (OMC-Pd) with Pd thicknesses around 10 μm, H2 permeances of 1.03·10−3 mol m−2 s−1 Pa−0.5 at 400 °C, and high ideal selectivity αH2/N2 ≥ 24,000. It should be noted that H2 permeance has been increased up to 6 times in comparison with other ELP-PP membranes without any intermediate layer and 2 times in contrast to membranes containing dense CeO2 particles instead of the mesoporous ones for the intermediate layer. Moreover, Pd-membranes so prepared (OMC-Pd) have shown excellent mechanical resistance in a wide variety of operating conditions such as temperature, pressure, and permeate flux direction, maintaining a high H2-selectivity without delamination or peeling. These properties were also maintained in case of feeding different H2/N2 mixtures, where the concentration-polarization effect seems to stabilize for lower H2 concentration values in the feed stream, not being noticeably influenced by temperature.

Redox Active Hexanuclear Mixed Valence Dicationic Ce(III)/Ce(IV) Coordination Clusters

A series of mixed valence hexanuclear dicationic coordination clusters containing two µ4‐O2– bridges with general formula M2+(X–)2 [M = CeIV2CeIII4(µ4‐O)2(L–R)4(val)6(H2O)2; 12+, 32+: R = H, 22+: Me; 12+, 22+: X = CeIII2(val)3(NO3)4, 32+: X = NO3] were synthesized, isolated and characterized. The reaction of cerium(III)nitrate hexahydrate with Schiff base ligand (H2L–R) and o‐vanillin (val‐H) under basic condition led to the formation of M2+(X–)2 and the reaction progress was monitored by mass spectrometric studies. The molecular structures of all complexes were unambiguously characterized by single‐crystal X‐ray diffraction. The magnetic susceptibility measurements of M2+(X–)2 showed that the Ce(III) ions are weakly antiferromagnetically coupled. Thermal stability and molar conductivity of M2+(X–)2 were also studied. Complex 32+(X–)2 was further studied by X‐ray photoelectron spectroscopy to confirm the oxidation states of Ce(III/IV) ions. The M2+ cation was shown to catalyze the TEMPO‐free oxidation of functionalized benzyl alcohols quantitatively to the corresponding benzaldehyde derivatives at 100 °C in presence of aerial O2 using DMF as the solvent.

Nano-fibrous scaffold with curcumin for anti-scar wound healing.

Open deep cuts and wounds often take a long time to heal and may cause infection and scar formation. A simple biomimetic electrospun nano-fibrous antimicrobial dressing material loaded with dual anti-oxidants has been developed to address this problem. A composite nano-fibrous material (PVP-Ce-Cur NF) comprising polyvinyl pyrrolidone (PVP), cerium nitrate hexahydrate (Ce(NO3)3·6H2O) and curcumin was developed using the electrospinning technique. The surface characteristics of nanofibers were examined using standard analytical techniques. The antimicrobial activity was tested against Escherichia coli (gram -ve) and Staphylococcus aureus (gram+ve) bacterial species. The MTT assay using 3T6-Swiss albino fibroblast indicated that the nano-fibrous dressing material was hemocompatible and devoid of cytotoxicity. Direct application of the PVP-Ce-Cur NF dressing material on full-thickness circular excision wound in model wistar rats displayed complete healing and re-epithelialisation without any scar within 20days. A well-regulated level of hydroxyproline, superoxide dismutase (SOD) and catalase in granulation tissues indicated PVP-Ce-Cur NF as a potential wound dressing material with the anti-scar property.