Bimetallic palladium–gold nanoparticles synthesized in ionic liquid microemulsion

The palladium and gold precursors were dissolved in dispersive and continuous phase of ionic liquid microemulsion (H₂O/Triton X-100 (TX-100)/1-butyl-3-methylimidazolium hexafluorophosphate), respectively. [PdCl₆]^2? ions were reduced in situ by TX-100 in dispersive phase (H₂O) to prepare Pd nanoparticles (NPs) and then [AuCl₄]^? crossed through the interface film and reacted with the as-prepared Pd NPs to form Pd₄Au NPs. The as-prepared Pd₄Au NPs were characterized by transmission electronic microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and ultraviolet–visible spectroscopy. The as-prepared Pd₄Au NPs suspension and carbon nanotubes (CNTs) suspension were vigorously stirred to prepare the electrocatalyst supported on the CNTs with a total metal loading of 20?wt.% (denoted by Pd₄Au/CNTs). Cyclic voltammetry and chronoamperometry tests show that the Pd₄Au/CNTs are very promising for the oxidation of ethanol in alkaline medium. The result can be attributed to the synergistic effect between Pd and Au during the catalytic process.     

Ionic liquid [bmim][BF4] acts as solvent and promoter for synthesis of halo-containing N-arylphthalimides

A new synthetic process of N-arylphthalimide and halo-containing N-arylphthalimides through the reaction between phthalic anhydride and aromatic amines bearing halo groups in[bmim][BF_4]was described,ionic liquid[bmim][BF_4]acted as the dual role of solvent and promoter.     

Sol–gel encapsulation of acid phosphatase in the presence of the ionic liquid [BMIM][BF4]

Abstract  

The effect of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF₄]) on acid phosphatase (APase) from wheat germ in solution and in the sol–gel-encapsulated form was investigated to explore new methods of enzyme preparation with improved catalytic performance. APase was encapsulated in hydrogel beads made from tetramethyl orthosilicate. Compared with free APase, 20–28% enzymatic activity was retained in over nine catalytic cycles. Sol–gel encapsulation improved the thermal stability of APase. Heat shock exposure at 60 °C for 1 h resulted in activity decreasing by a factor of three, only, for sol–gel-encapsulated APase, in contrast with a factor of nine decrease for free APase. Addition of 10% v/v [BMIM][BF₄] did result in a slight decrease of enzymatic activity for free and sol–gel-encapsulated APase, but resulted in a remarkable increase in alkaline pH tolerance of sol–gel-encapsulated APase.     

Synthesis of nanostructural Yttrium fluorosilicate glass ceramic via sol–gel method

Journal of Sol-Gel Science and Technology - The yttrium fluorosilicate glass ceramic pieces were prepared by sol–gel method starting from yttrium acetate, trifluoroacetic acid, and...     

Ionic Liquid [bmim][BF4] as a Green Medium for Passerini Reaction

The Passerini reaction, a three-component condensation reaction of carboxylic acid, aldehyde and isocyanide constructing an α-acyloxycarboxamide in a single step, was first discovered by Passerini about 80 years ago1. Since then, this reaction has been w…     

Synthesis of YCrO3 nanoparticles through PAA assisted sol–gel route

We report the synthesis of nanocrystalline phase-pure YCrO₃ powders by a poly acrylic acid (PAA) assisted sol–gel process at a comparatively low calcination temperature of 600 °C. The role of PAA in the powder processing was investigated systemically using Fourier transform infrared (FTIR) spectroscopy, differential thermal and thermogravimetric analyzer (DT/TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). PAA is found to have the desirable property of forming stable complexes with the cations, Y³⁺ and Cr³⁺ at a low pH. FTIR results demonstrated that in the gel-precursor, the carboxylate groups of PAA bond to Y³⁺ and Cr³⁺ in a monodentate and a bridging bidentate configuration, respectively, owing to the properties of Cr³⁺ giving the best correlation with PAA. The obtained particles have capsule-like morphology with a mean diameter of 40 nm. It is presumed that this morphology is due to the extended-chain configuration of PAA in the aqueous solution. The method showed a good control over particle size, morphology, chemical homogeneity, stoichiometry and agglomeration of the powders.     

Synthesis of LiNiPO4 via citrate sol–gel route

Journal of Sol-Gel Science and Technology - In this paper, LiNiPO4 powders were prepared by sol gel method using citric acid as chelating agent. The article investigated the effect of annealing...     

离子液体[bmim][BF4]对联苯甲酰光化学反应影响的瞬态吸收光谱

利用纳秒级激光光解瞬态吸收光谱研究了联苯甲酰(BZ)在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF₄])与乙腈(MeCN)混合体系中的光化学反应行为. 考察了探针分子BZ存在下[bmim][BF₄]/MeCN比例对体系中化学反应动力学的影响. 实验发现: 在N₂饱和条件下, BZ溶液经激光辐照后产生的激发三线态³BZ^*遵循一级反应动力学规律衰减. 离子液体(IL)相对比例增加对³BZ^*瞬态吸收峰的位置和强度没有产生明显影响. 但离子液体体积分数V_IL的变化对[bmim][BF₄]/MeCN混合溶剂中光诱导电子转移的影响却非常显著, 总体上电子转移产生的自由基的表观生成速率常数k_gr随[bmim][BF₄]的V_IL增大而减小. 在[bmim]BF₄]比例足够大的情况下, ³BZ^*与三乙胺或四甲基对苯二胺之间的电子转移被抑制.     

室温离子液体[bmim][BF4]和水混合物的计算机模拟研究

针对室温离子液体[bmim][BF₄]和水的混合物, 用分子动力学模拟研究了溶液的微观组成与浓度的关系. 模拟结果表明：该混合物中各组分间的径向分布函数随[bmim][BF₄]摩尔分数的增加呈有规律的变化；在此基础上计算了溶液的局部组成以及组分间的缔合因子, 进一步考察了各组分间的相互作用情况；另外基于Kirkwood-Buff理论估算了混合物的偏摩尔体积、等温压缩因子以及活度系数对浓度的偏导数, 对于理解离子液体与水之间的交互作用具有一定的参考意义.     

Excess molar enthalpies for [Bmmim][BF4] + [Bmim][BF4] or [Emim][BF4] + cyclopentanone or cyclohexanone mixtures

Journal of Thermal Analysis and Calorimetry - In recent years, studies on mixtures consisting of ionic liquids and organic solvents have gained importance for the application of such mixtures for...     

Non-aqueous sol–gel preparation of carbon-supported nickel nanoparticles

This work addresses the novel non-aqueous sol–gel process preparation of carbon-supported nickel nanoparticles. In the sol–gel process, ethanol, nickel nitrate or nickel (П) acetylacetonate, and citric acid were used as solvent, source of metallic element, and chelating agent, respectively. Hexadecylamine (HDA), oleic acid and oleylamine were used as surfactants. The calcination process was performed under protecting Ar or N₂ flowing. Carbon supported nickel nanoparticles can be prepared by this sol–gel process. Moreover, no grain growth occurs in a temperature range of 200 K, meaning that the grain size of the nickel nanoparticles can be controlled in this sol–gel process. The nickel nanoparticles can display typical superparamagnetic behavior at room temperature when HDA has been used. This novel method is expected to have wide applications in the field of metallic nanoparticles.     

Synthesis and sol–gel assembly of nanophosphors

Some recent works made in our group on inorganic nanophosphors are briefly reviewed in this paper. We first present the synthesis of highly concentrated semiconductor quantum dot colloids allowing the extension of the well-known oxide sol–gel process to chalcogenide compounds. Secondly, we show the synthesis and the chemical functionalization of lanthanide-doped insulator nanoparticles. In particular, the annealing process of these particles at high temperature leads to highly bright nanocrystals, which can be used as biological luminescent labels or for integration in transparent luminescent coatings. Finally, we consider luminescent transition metal clusters, which combine the inorganic structure of nanoparticles with the monodispersity and the easy functionalization of the organic molecules. Emphasis is put on the original thermochromic luminescence properties of copper iodide clusters trapped in siloxane-based films.     

Synthesis and characterization of tellurium-doped CdO nanoparticles thin films by sol–gel method

In this work, tellurium (Te) doped CdO nanoparticles thin films with different Te concentrations (1, 3, 5, 7 and 10 %) were prepared by sol–gel method. The effects of Te doping on the structural, morphological and optical properties of the CdO thin films were systematically studied. From X-ray diffraction spectra, it has seen that all of thin films were formed polycrystalline and cubic structure having (111), (200) and (311) orientations. The structure of CdO thin films with Te-dopant was formed the unstable CdTeO₃ monoclinic structure crystal plane ( $ {\bar{\text{1}}\text{22}} $ 1 ¯ 22 ), however, the intensity of this unstable peak of the crystalline phase decreased with the increase of Te-doping ratio. The strain in the structure is also studied by using Williamson-Hall method. From FE-SEM images, it has seen that particles have homogeneously distributed and well hold onto the substrate surface. Additionally, grain size increases from 27 to 121 nm with the increase of Te-doping ratio. Optical results indicate that 1 % Te-doped CdO thin film has the maximum transmittance of about 87 %, and the values of optical energy band gap increases from 2.50 to 2.64 eV with the increase of Te-doping ratio. These results make Te-doped CdO thin films an attractive candidate for thin film material applications.     

One-step Synthesis of Dipyrromethanes in the Presence of Ionic Liquid [Hmim]BF4

Dipyrromethanes were obtained in moderate yields by the condensation of ketone and pyrrole in the presence of ionic liquid [Hmim]BF4 without using any strong acid and other organic solvent.     

Synthesis and characterization of nitrogen-doped TiO2 nanoparticles prepared by sol–gel method

The N-doped TiO₂ has been synthesized by sol?Cgel method, using titanium isopropoxide, isopropanol and an aqueous solution of ammonia with ratio 2:1:10. The concentrations used for the NH₃ aqueous solution were 3, 7, 10 and 15?%. The samples have been analysed by X-ray diffraction, electron microscopy (SEM and TEM) thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), micro-Raman spectroscopy and diffuse reflectivity. TEM, SEM, DSC and TGA showed that the morphology is influenced by the presence of N^3? ions but not by the concentration of the solution. Instead reflectance gave us a relation between values of the energy gap and the concentration of N^3? ions: the gap between valence and conduction band lowers as the concentration of NH₃ in the starting solution increases. From these results we can say that the properties of the material have been tuned by doping with nitrogen ions because the particles absorb more light in the visible range, and this is important for photovoltaic and photocatalytic applications.     

Synthesis and characterization of sol–gel alumina nanofibers

Abstract Alumina nanofibers of high aspect ratio with surface area of >300 m² g⁻¹ has been prepared successfully in bulk quantities by the sol–gel method. The synthesis parameters including the binary water–alcohol solvent system to aluminium isopropoxide ratio, pH, type of solvent and aging temperature affect the uniformity and formation of nanofibers. It is proposed that alumina nanofibers were formed by the curling of the nanosheets upon condensation after the hydrolysis. The phase evolution of alumina nanofibers from pseudoboehmite to α phase has been shown by XRD and FTIR. ²⁷Al NMR investigations show that the Al atoms are six and four coordinated. The morphology of the alumina nanofibers does not change much as the calcination temperature was increased. In addition, the average pore size increases and the BET surface area decreases as a function of calcination temperature. The thermal behavior of alumina nanofibers was investigated by TGA. Graphical Abstract      

Lactic acid based sol–gel process of Ag nanoparticles and crystalline phase control of Ni particles in aqueous sol–gel process

Nickel and silver particles were prepared by using sol–gel auto-combustion method under N₂ atmosphere where lactic acid was applied as chelating agent. The synthesis of nickel particles was carried out at various pH conditions (2–7), resulting in the face-centered-cubic or hexagonal-close-packed crystalline nickel phase. The morphology and structure of synthesized nickel particles and silver nanoparticles were characterized by X-ray diffraction, transmission electron microscope, energy dispersive X-Ray spectroscopy and differential scanning calorimetry-thermogravimetric analysis. The results show that the spherical Ag nanoparticles with diameters in the range of 18–27 nm and narrow size distribution can be obtained by this sol–gel process.