Showing papers on "Lanthanum published in 2011"
TL;DR: In this article, a technique is described for deposition of gold nanoparticles under vacuum, enabling consistent energy referencing of X-ray photoelectron spectra obtained from lanthanum hydroxide La(OH)3 and in situ treated Lanthanum oxide La2O3 powders.
425 citations
TL;DR: In this article, the evaporation-induced self-assembly (EISA) in ethanolic solution of a triblock copolymer (Pluronic P123) was explored for the synthesis of ordered mesoporous alumina (MA) and supported metal oxides, using aluminum isopropoxide, aluminum chloride, and aluminum nitrate nonahydrate as aluminum precursors, and nickel, magnesium, iron, chromium, copper, cerium, lanthanum, yttrium, calcium, tin chlorides, or nitrates as metal precurs
Abstract: The evaporation-induced self-assembly (EISA) in ethanolic solution of a triblock copolymer (Pluronic P123) is explored for the synthesis of ordered mesoporous alumina (MA) and MA-supported metal oxides, using aluminum isopropoxide, aluminum chloride, and aluminum nitrate nonahydrate as aluminum precursors, and nickel, magnesium, iron, chromium, copper, cerium, lanthanum, yttrium, calcium, tin chlorides, or nitrates as metal precursors. The as-synthesized mesoporous oxides were characterized by a variety of techniques, such as thermogravimetry, Fourier transform infrared spectroscopy, nitrogen adsorption, small- and wide-angle X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectrometry, elemental mapping, and CO2 and NH3 temperature-programmed desorption. It is shown that the EISA strategy in the presence of polymeric template not only is well-suited for the synthesis of ordered MAs and MA-supported metal oxides with tailored adsorption and framework properties...
268 citations
TL;DR: The local spectroscopic and theoretical results indicate that the interfacial conductivity is dependent on electronic correlations that decay spatially into the SrTiO3 matrix, which can lead to new functionalities in designed heterostructures.
Abstract: The formation of two-dimensional electron gases (2DEGs) at complex oxide interfaces is directly influenced by the oxide electronic properties. We investigated how local electron correlations control the 2DEG by inserting a single atomic layer of a rare-earth oxide (RO) [(R is lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), or yttrium (Y)] into an epitaxial strontium titanate oxide (SrTiO3) matrix using pulsed-laser deposition with atomic layer control. We find that structures with La, Pr, and Nd ions result in conducting 2DEGs at the inserted layer, whereas the structures with Sm or Y ions are insulating. Our local spectroscopic and theoretical results indicate that the interfacial conductivity is dependent on electronic correlations that decay spatially into the SrTiO3 matrix. Such correlation effects can lead to new functionalities in designed heterostructures.
198 citations
TL;DR: The thermodynamic parameters were determined which revealed the feasibility, spontaneity, and endothermic nature of adsorption, suggesting that the second-order model best fits the experimental data.
170 citations
TL;DR: An inorganic/organic hybrid adsorbent for phosphate adsorption was synthesized by introducing lanthanum (La) onto diamino modified MCM-41 and the results indicated that the Langmuir model fitted the experiment data better than the Freundlich model.
143 citations
TL;DR: In this article, high purity W and W-0.9La(2)O(3) (wt.%) nanopowders were produced by a wet chemical route.
139 citations
TL;DR: In this paper, heterogeneous ruthenium-based catalysts were applied in the selective, aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, to form 2,5-furandicarboxylic acid.
Abstract: Heterogeneous ruthenium-based catalysts were applied in the selective, aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, to form 2,5-furandicarboxylic acid. The oxidation reactions were performed in water with dioxygen as the oxidant at different pressures without added base. Catalysts were prepared by depositing catalytically active Ru(OH)x species on a number of different supports, such as titanium-, aluminum-, cerium-, zirconium-, magnesium- and lanthanum oxides, magnetite, spinel, hydrotalcite and hydroxyapatite. All the catalysts were found to be active in the oxidation reactions, and the choice of support was demonstrated to be important for the catalytic performance.
118 citations
TL;DR: The phosphate‐binding equivalent dose may be useful in comparing changes in phosphate binder prescription over time when multiple binders are being prescribed, when estimating an initial binder prescriptions, and also in phosphate kinetic modeling.
Abstract: Phosphate binders include calcium acetate or carbonate, sevelamer hydrochloride or carbonate, magnesium and lanthanum carbonate, and aluminum carbonate or hydroxide. Their relative phosphate-binding capacity has been assessed in human, in vivo studies that have measured phosphate recovery from stool and/or changes in urinary phosphate excretion or that have compared pairs of different binders where dose of binder in each group was titrated to a target level of serum phosphate. The relative phosphate-binding coefficient (RPBC) based on weight of each binder can be estimated relative to calcium carbonate, the latter being set to 1.0. A systematic review of these studies gave the following estimated RPBC: for elemental lanthanum, 2.0, for sevelamer hydrochloride or carbonate 0.75, for calcium acetate 1.0, for anhydrous magnesium carbonate 1.7, and for "heavy" or hydrated, magnesium carbonate 1.3. Estimated RPBC for aluminum-containing binders were 1.5 for aluminum hydroxide and 1.9 for aluminum carbonate. The phosphate-binding equivalent dose was then defined as the dose of each binder in g × its RPBC, which would be the binding ability of an equivalent weight of calcium carbonate. The phosphate-binding equivalent dose may be useful in comparing changes in phosphate binder prescription over time when multiple binders are being prescribed, when estimating an initial binder prescription, and also in phosphate kinetic modeling.
117 citations
TL;DR: In this article, Ni-RE (RE = rare earth, La, Ce) materials were obtained by the solid state reaction using as Ni source: a) metal acetylacetonates and b) metal powders while rare earth element was added from acetyl acetonates These materials were synthesized for 3h at different temperatures (800°C or 900°C, 1000°C and 1200°C) in order to evaluate their electrochemical performance on the Hydrogen Evolution Reaction (HER).
114 citations
TL;DR: In this paper, Lanthanum hydroxide nanoparticles were prepared by facial hydrothermal processing from the resulted product at 110°C for 24-h. The role of surfactant, calcination temperature and sonication time were investigated on the morphology and particle size of the products.
113 citations
TL;DR: In this article, a reduced-temperature solid oxide fuel cell (SOFC) with thin strontium-and magnesium-doped lanthanum gallate (LSGM) electrolytes and nano-scale Ni anodes was developed.
Abstract: Reduced-temperature solid oxide fuel cells (SOFCs), featuring thin strontium- and magnesium-doped lanthanum gallate (LSGM) electrolytes and nano-scale Ni anodes, showed high power densities of 1.20 W cm−2 at 650 °C and 0.39 W cm−2 at 550 °C when operated on humidified hydrogen fuel and air oxidant.
TL;DR: Nano-crystalline W-1%Y(2)O(3) (wt.%) powder was produced by a modified solution chemical reaction of ammonium paratungstate (APT) and yttrium nitrate as discussed by the authors.
TL;DR: In this article, a facile sol-gel method was used to synthesize titanium dioxide photocatalysts co-doped with iron (III) and lanthanum.
TL;DR: In this article, the effect of rare-earth addition to barium zirconate titanate (BZT) ceramics was analyzed and a direct relation between transition temperature and tunability was discussed.
TL;DR: In this paper, the thermoelectric properties of SrTiO3 doped with lanthanum and dysprosium were studied using the conventional solid-state reaction method.
Abstract: To study the thermoelectric properties of SrTiO3 doped with lanthanum and dysprosium, ceramic samples were prepared using the conventional solid-state reaction method. The total doping amount was fixed at 20 mol% with different amounts of lanthanum and dysprosium contents. The X-ray diffraction pattern suggests that the main crystal structure is cubic perovskite with a small amount of the second phase of Dy2Ti2O7. Scanning electronic microscope surface morphology images revealed that the ceramic samples consisted of homogeneous grains with an average grain size of 4.1–6.2 μm. The electrical conduction of the samples as a function of temperature had similar behavior to that of metallic conductivity. The Seebeck coefficients were negative, which indicates that electrons were the dominant carriers. As the dysprosium content increased, both the electrical conductivity and thermal conductivity decreased; in contrast, the absolute value of the Seebeck coefficient increased. The power factor reached 1318 μW/K2m at 570 K with 12% dysprosium and 8% lanthanum doped in SrTiO3. The lowest thermal conductivity was 2.3 W/mK for the sample with 20% dysprosium as a dopant. The maximum figure of merit (ZT) of 0.36 at 1076 K was obtained for SrTiO3 doped with 12% dysprosium and 8% lanthanum, which is a result of the high power factor combined with low thermal conductivity.
TL;DR: In this article, the authors investigated the solvent extraction of thorium, some rare earth elements (including lanthanum, cerium and yttrium) and iron in order to determine their optimum separation conditions.
TL;DR: In this article, the area specific resistance (ASR) of a symmetrical cell with a layered cathode structure consisting of a thin compact LNO layer between the dense electrolyte and porous electrode was investigated by AC impedance spectroscopy.
TL;DR: In this paper, the effect of lanthanum substitution on the phase composition, lattice parameters and magnetic properties of barium hexaferrite has been studied in samples synthesized in ammonium nitrate melt.
TL;DR: The nature, concentration, and location of cationic lanthanum species in faujasite-type zeolites (zeolite X, Y and ultrastabilized Y) have been studied in order to understand better their role in hydrocarbon activation as discussed by the authors.
Abstract: The nature, concentration, and location of cationic lanthanum species in faujasite-type zeolites (zeolite X, Y and ultrastabilized Y) have been studied in order to understand better their role in hydrocarbon activation. By combining detailed physicochemical characterization and DFT calculations, we demonstrated that lanthanum cations are predominantly stabilized within sodalite cages in the form of multinuclear OH-bridged lanthanum clusters or as monomeric La3+ at the SI sites. In high-silica faujasites (Si/Al = 4), monomeric [La(OH)]2+ and [La(OH)2]+ species were only found in low concentrations at SII sites in the supercages, whereas the dominant part of La3+ is present as multinuclear OH-bridged cationic aggregates within the sodalite cages. Similarly, in the low-silica (Si/Al = 1.2) La–X zeolite, the SI′ sites were populated by hydroxylated La species in the form of OH-bridged bi- and trinuclear clusters. In this case, the substantial repulsion between the La3+ cations confined within the small sodali...
TL;DR: In this paper, the authors performed cation diffusion experiments within the framework of the evaluation of long-term stability of gadolinium doped ceria acting as a reaction barrier between cathode and electrolyte materials.
TL;DR: In this paper, the influence of lanthanum on the structure and properties of the precursors, as well as on the catalytic activity and stability of their derived catalyst on biogas reforming was investigated.
TL;DR: In this article, the effect of various synthesis parameters like lanthanum loading, stirring time and drying temperature on fluoride removal has been studied and it was observed that the synthesis parameters have significant influence on development of LCF and in turn on the fluoride removal capacity.
TL;DR: In this paper, the underlying mechanisms involved in the interaction of lanthanides (lanthanum, cerium, europium and ytterbium) with a brown marine alga, Turbinaria conoides in quaternary mixtures were elucidated.
TL;DR: In this paper, it was found that La 0.6 Ca 0.4 FeO 3 has the highest catalytic activity for methane combustion, and the linear dependence of T 50 on the amount of Fe 4+ (%) suggest that the active sites for the methane combustion are directly related to this unusual oxidation state of iron.
TL;DR: In this paper, the properties of the compounds La 0.33 Sr 0.67 Ti 0.92 X 0.08 O 3+ δ were investigated in the search for alternative solid oxide fuel cell anodes.
TL;DR: In this article, the synthesis and the study of physico-chemical and catalytic properties of a series of lanthanum manganite perovskite-type oxide using the one-step combustion method were investigated.
Abstract: The present work deals with the synthesis and the study of physico-chemical and catalytic properties of a series of lanthanum manganite perovskite-type oxide using the one-step combustion method. Glycine was used as complexing agent and fuel. Seven glycine-to-nitrate ratios from 0.32 to 0.8 were investigated. XRD patterns show a single phase perovskite type oxide when glycine-to-nitrate ratio is above 0.37. Glycine/nitrate ratio affects significantly the surface areas, which range in 18–37 m2/g. The use of fuel-rich precursor allows an enhancement of the specific surface area, the reducibility of manganese and the mobility of desorbed oxygen. The light-off temperature for 50% and 90% of methane conversion was found to be directly related to surface areas. The highest catalytic activity was obtained for glycine-to-nitrate ratio of 0.8, which exhibits the highest superficial concentration of manganese and the highest amount of active oxygen. This catalyst shows also a good thermal stability.
TL;DR: In this article, the effect of lanthanum content on physicochemical properties and catalytic performance of mesoporous (40-x)NixLa catalysts in the steam reforming of liquefied natural gas (LNG) was investigated.
TL;DR: The present La(III) catalyst was highly effective for the chemoselective transesterification in the presence of competitive 1°- and 2°-amines and esters were obtained in good to excellent yields as colorless materials without an inconvenient workup procedure.