LaCoO_3与LaFeO_3结构与CO催化氧化性能比较研究

采用柠檬酸 -乙醇络合溶胶 -凝胶法合成了两个单一相钙钛矿型稀土复合氧化物 La-Co O3和 La Fe O3并对其进行了结构 ,电阻率 ,比表面积 ,表面氧特性和 CO氧化催化活性比较研究 ,结果表明 ,它们有几乎相近的大比表面积 ,但它们的晶系不同 ,La Co O3属三方晶系 ,La Fe O3属正交晶系 ,La Co O3比 La Fe O3具有高的吸附氧量和导电性及 CO低温催化氧化活性 。

Photocatalytic Degradation of Water-Soluble Dyes by LaCoO_3

Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3 . The results show that the pervoskite type oxide LaCoO 3 has good photocatalytic activity.Studied by X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is found to be related with factors such as the d electron structure of ion Co 3+ ,Co—O binding energy and adsorbed oxygen on the surface etc.

Photocatalytic Degradation of Water-Soluble Dyes by LaCoO3

Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3 . The results show that the pervoskite type oxide LaCoO 3 has good photocatalytic activity.Studied by X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is found to be related with factors such as the d electron structure of ion Co 3+ ,Co—O binding energy and adsorbed oxygen on the surface etc.

Preparation and properties of composite polymer electrolyte modified with nano-size rare earth oxide

Poly（vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte （CPE） modified with CeO2, La2O3 and Y2O3 nano-rare earth oxides was prepared by phase inversion technique. Physical and chemical properties of the modified CPEs were studied by SEM, TG-DSC and electrochemical methods. The results show that the CPE modified with 10% La2O3 （mass fraction） has the best practical applicability, which indicates that the thermal and electrochemical stability can reach over 400 ℃ and 4.5 V, respectively, and temperature dependence of ionic conductivity follows Vogel-Tamman-Fulcher （VTF） relationship and ionic conductivity at room temperature is up to 3.3 mS/cm. The interfacial resistance Ri reaches a stable value about 557 Ω after 6 d storage.

Effects of various rare earth oxides on morphology and size of oxide dispersion strengthening(ODS)-W and ODS-Mo alloy powders

Ultrafine oxide dispersion strengthening(ODS)-Mo and ODS-W alloy powders containing different types of oxide nanoparticles were successfully synthesized by spraying method(solid−liquid mixing method)combined with the reductions with carbon black and hydrogen in sequence.It is concluded that the solution concentration and type of rare earth oxide have no effect on the grain size of ODS-Mo alloy powder,but have obvious effect on that of ODS-W alloy powder.The higher the concentration of rare earth solution is,the smaller the average grain size of ODS-W alloy powder is.Furthermore,compared with doping with CeO_(2),the grain sizes of reduction products of La_(2)O_(3) and Y_(2)O_(3) doped WO_(3) are relatively larger.Compared with the undoped case,there is almost no change for grain size of ODS-Mo alloy powder,while the grain size of ODS-W alloy powder becomes much larger.This is probably due to the appearance of the composite oxide(such as La_(2)WO_(6))formed by the reaction between tungsten oxide and rare earth oxides,which promotes the heterogeneous nucleation and growth of tungsten grains during the reduction process of ODS-W,while there is no complex oxide composed of molybdenum and rare earth oxides in the reduction process of ODS-Mo.

Specific Adsorption of Trivalent La, Ce and Y by Soils and Ferro-manganese Oxides and Its Mechanism

In this paper, the adsorption-desorption variations of trivalent La, Ce, Y and mixed rare earths are discussed. The curves of pH-rare earth element adsorption were very well fitted to the equation: InD =a+b pH. The selectivity of RE (rare earth element) ions by the samples decreased in the following order: Ce> RE> La> Y, but the sequences were: La> Ce> Y on kaolinite and Y> La on amorphous iron oxide. Since the trivalent RE ions existed in the form of RE(OH)2+ in the solutions from pH < 5.45 to 7.0, the ratio of H+ displaced to RE3+ adsorbed in micromole was proposed to be about 2. The specific adsorption mechanism for RE was proposed to be that the RE ions complexed with oxide surface and the ion-surface complex of Ce3+ promoted oxidization on Mn hydroxide.

Synthesis of gold/rare-earth-vanadate core/shell nanorods for integrating plasmon resonance and fluorescence

The nanoscale core/shell heterostructure is a particularly efficient motif to combine the promising properties of plasmonic materials and rare-earth compounds; however, there remain significant challenges in the synthetic control due to the large interfacial energy between these two intrinsically unmatched materials. Herein, we report a synthetic route to grow rare-earth-vanadate shells on gold nanorod （AuNR） cores. After modifying the AuNR surface with oleate through a surfactant exchange, well-packaged rare-earth oxide （e.g., Gd2O3：Eu） shells are grown on AuNRs as a result of the multiple roles of oleate. Furthermore, the composition of the shell has been altered from oxide to vanadate （GdVO4：Eu） using an anion exchange method. Owing to the carefully designed strategy, the AuNR cores maintain the morphology during the synthesis process; thus, the final Au/GdVO4： Eu core/shell NRs exhibit strong absorption bands and high photothermal efficiency. In addition, the Au/GdVO4：Eu NRs exhibit bright Eu^3＋ fluorescence with quantum yield as high as -17%; bright Sm^3＋ and Dy^3＋ fluorescence can also be obtained by changing the lanthanide doping in the oxide formation. Owing to the attractive integration of the plasmonic and fluorescence properties, such core/shell heterostructures will find particular applications in a wide array of areas, from biomedicine to energy.

Ultrathin lanthanide oxides nanomaterials： synthesis, properties and applications

Over the past decade, ultrathin lanthanide oxides （Ln2O3, Ln = La to Lu） nanomaterials have been intensively studied in the fields of rare earth materials science. This unique class of nanomaterials has shown many unprecedented properties （big surface area, high surface effect, physical and chemical activities） and is thus being explored for numerous promising applications. In this review, a brief introduction of ultrathin Ln2O3 nanomaterials was given and their unique advantages were highlighted. Then, the typical synthetic methodologies were summarized and compared （thermal decomposition, solvothermal, soft template, co-precipition and microwave etc.）. Due to the high surface effect, some promising applications of ultmthin Ln203 nanomaterials, such as drug delivery and catalysis of CO oxidation, were reviewed. Finally, on the basis of current achievements on ultrathin Ln203 nanomaterials, personal perspectives and challenges on future research directions were proposed.