Construction and Photoluminescence of Monophase Hybrid Materials Derived from a Urea-Based Bis-Silylated Bipyridine

A urea-based bis-silylated bipyridine ligand derived from 4,4'-diamino-2,2'-bipyridine has been prepared. Organic-inorganic hybrid materials with a high loading of lanthanide 2,2-bipyridine moieties were obtained by using the silylated bipyridine as the only siloxane network precursor in the presence of lanthanide ions (or lanthanide complexes). The in-situ formation of lanthanide complexes from lanthanide ions and the silylated bipyridine during the sol-gel processing was confirmed by the luminescence behavior of the obtained hybrid materials and that of the corresponding pure lanthanide complex [Ln(bpy)(2)Cl-3 center dot 2H(2)O].

High proton conductive advanced hybrid membrane based on sulfonated Si-SBA-15

Composite membranes based on Sulfonated poly(ether ether ketone) (SPEEK) and sulfonated organically modified Si-SBA-15 (S-SBA-15) were investigated with the purpose of increasing the proton conductivity. The novelty of the composite membranes was attributed to two special structures and different ion exchange capacities (IEC) of S-SBA-15 fillers, which were embedded in membranes. The typical hexagonal channels array of S-SBA-15 was confirmed by XRD and TEM. The regular vermiculate and amorphous structures of the inorganic fillers were proved by SEM. Composite membranes were prepared through common solvent casting method. SEM images indicated that the inorganic filler with regular structure dispersed homogeneously in the composite membranes, but the amorphous filler caused an agglomeration phenomenon at the same loading content.

Removal of Cr(III, VI) by quaternary ammonium and quaternary phosphonium ionic liquids functionalized silica materials

A series of silica-based organic–inorganic hybrid materials were prepared by the sol–gel process for Cr(III) and Cr(VI) adsorption. These silica materials generally had high surface areas, good physical–chemical stability and high thermal stability. Trialkylmethylammonium bis 2,4,4-trimethylpentylphosphinate ([A336][C272]) and trihexyl(tetradecyl)phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) were explored as porogens to prepare porous silica and as extractants to extract chromium ions. Cyphos IL 104 and [A336][C272] functionalized silica sorbents (SG-2, SG-5) can be effectively used for the removal of Cr(III) and Cr(VI) from aqueous solutions by adjusting pH values, whereas trialkylmethylammonium chloride (Aliquat 336) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) functionalized silica sorbents (SG-3, SG-4) can only be used for the removal of the single chromium species, Cr(VI) or Cr(III).

Organic-inorganic hybrid material for the cells immobilization: Long-term viability mechanism and application in BOD sensors

In this paper, organic-inorganic hybrid material, which is composed of silica and the grafting copolymer of poly (vinyl alcohol) and 4-vinylpyridine (PVA-g-P(4-VP)), was employed to immobilize Trichosporon cutaneum strain 2.570 cells. Cells entrapped into the hybrid material were found to keep a long-term viability. The mechanism of such a long-term viability was investigated by using confocal laser scanning microscopy (CLSM). Our studies revealed that arthroconidia produced in the extracellular material might play an important role in keeping the long-term viability of the immobilized microorganism. After the arthroconidia were activated, an electrochemical biochemical oxygen demand (BOD) sensor based on cell/hybrid material-modified supporting membrane was constructed for verifying the proposed mechanism.

Pt Nanoparticles Supported on TiO2 Colloidal Spheres with Nanoporous Surface: Preparation and Use as an Enhancing Material for Biosensing Applications

An easy surface-modified method has been developed to link -NH2 groups to the TiO2 colloidal spheres with nanoporous surface (f-TiO2). It was found that the as-prepared f-TiO2 is positively charged in neutral conditions and could act as an electrostatic anchor for nanosructures with opposite charge, Furthermore, platinum nanoparticles (Pt NPs) are successfully assembled on the f-TiO2 mainly via electrostatic interaction to fabricate a new kind of Pt NPs/TiO2 hybrid nanomaterial (f-TiO2-Pt NPs). The morphology, structure, and composition of the hybrids were characterized by the means of diverse techniques such as transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, and Raman spectra. Electrochemical experiments indicate the electrode modified with f-TiO2-Pt NPs shows prominent electrocatalytic activity toward the oxidation of hydrogen peroxide.

High-efficiency and low-cost hybrid nanomaterial as enhancing electrocatalyst: Spongelike AWN core/shell nanomaterial with hollow cavity

A high-efficiency and low-cost spongelike Au/Pt core/shell electrocatalyst with hollow cavity has been facilely obtained via a simple two-step wet chemical process. Hollow gold nanospheres were first synthesized via a modified galvanic replacement reaction between Co nanoparticles in situ produced and HAUCl(4). The as-prepared gold hollow spheres were employed as seeds to further grow spongelike Pt shell. It is found that the surface of this hybrid nanomaterial owns many Pt nanospikes, which form a spongelike nanostructure. All experimental data including scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis-near-infrared spectroscopy have been employed to characterize the obtained Au/Pt hybrid nanomaterial. The rapid development of fuel cell has inspired us to investigate the electrocatalytic properties for dioxygen and methanol of this novel hybrid nanomaterial. Spongelike hybrid nanomaterial mentioned here exhibits much higher catalytic activity for dioxygen reduction and methanol oxidation than the common Pt electrode.

Polyaniline/Pt Hybrid Nanofibers: High-Efficiency Nanoelectrocatalysts for Electrochemical Devices

A simple and facile procedure to synthesize a novel hybrid nanoelectrocatalyst based on polyaniline (PANI) nanofiber-supported supra-high density Pt nanoparticles (NPs) or Pt/Pd hybrid NPs without prior PANI nanofiber functionalization at room temperature is demonstrated. This represents a new type of ID hybrid nanoelectrocatalyst with several important benefits. First, the procedure is very simple and can be performed at room temperature using commercially available reagents without the need for templates and surfactants. Second, ultra-high density small "bare" Pt NPs or Pt/Pd hybrid NPs are grown directly onto the surface of the PANI nanofiber, without using any additional linker. Most importantly, the present PANI nanofiber-supported supra-high density Pt NPs or Pt/Pd hybrid NPs can be used as a signal enhancement element for constructing electrochemical devices with high performance.

Carbon Nanotube/Silica Coaxial Nanocable as a Three-Dimensional Support for Loading Diverse Ultra-High-Density Metal Nanostructures: Facile Preparation and Use as Enhanced Materials for Electrochemical Devices and SERS

In this paper, we have reported a very simple strategy (combined sonication with sol-gel techniques) for synthesizing well-defined silica-coated carbon nanotube (CNT) coaxial nanocable without prior CNT functionalization. After functionalization with NH2 group, the CNT/silica coaxial nanocable has been employed as a three-dimensional support for loading ultra-high-density metal or hybrid nanoparticles (NPs) such as gold NPs, Au/Pt hybrid NPs, Pt hollow NPs, and Au/Ag core/shell NPs. Most importantly, it is found that the ultra-high-density Au/Pt NPs supported on coaxial nanocables (UASCN) could be used as enhanced materials for constructing electrochemical devices with high performance. Four model probe molecules (O-2, CH3OH, H2O2, and NH2NH2) have been investigated on UASCN-modified glassy carbon electrode (GCE). It was observed that the present UASCN exhibited high electrocatalytic activity toward diverse molecules and was a promising electrocatalyst for constructing electrochemical devices with high performance. For instance, the detection limit for H2O2 with a signal-to-noise ratio of 3 was found to be 0.3 mu M, which was lower than certain enzyme-based biosensors.

The effect of template phase on the structures of As-synthesized silica nanoparticles with fragile didodecyldimethylammonium bromide vesicles as templates

The effect of template phase on the structures of as-synthesized silica nanoparticles with fragile DDAB vesicles as templates is reported. It is found that the template phase plays a critical role in the growth process of silica: the unstable DDAB vesicles in liquid-crystalline phase often lead to the formation of mesostructured solid spheres, and the rather stable DDAB vesicles in gel phase lead to the formation of hollow spheres with less mesostructures.

Tris(2,2 '-bipyridyl) ruthenium(II) doped silica film modified indium tin oxide electrode and its electrochemiluminescent properties

An approach was reported to synthesize silica hybridized ruthenium bipyridyl complex through amidation reaction by covalent attachment of bis(bipyridyl)-4,4'-dicarboxy-2,2'-bipyridyl-ruthenium to (3-aminopropyl)-triethoxysilane. The hybrid complex then was gelatinized through acid catalytic hydrolysis method and a sol-gel modified indium, tin oxide electrode was prepared via spin coating technique. As prepared indium tin oxide electrode possesses good stability therein with excellent electrochemiluminescence behavior.

Synthesis and luminescent properties of europium (III) schiff base complexes covalently bonded to silica xerogels

A new kind of luminescent organic-inorganic hydrid material consisting of Eu(III)-schiff base complex covalently bonded to silica xerogel was synthesized via the sol-gel method using a Eu (N-propylene salicylimine ligand) complex modified with pendant triethoxysilane groups (Eu(III)(salenHSi)). The Eu(III)(salenHSi) complex is characterized by Fourier transform infrared (FT-IR) spectroscopy. Luminescent properties of the complex and the resulted hybrid silica xerogels have been investigated at room temperature.

Bifunctional magnetic-optical nanocomposites: Grafting lanthanide complex onto core-shell magnetic silica nanoarchitecture

Anew class of bifunctional architecture combining the useful functions of superparamagnetism and terbium complex luminescence into one material has been prepared via two main steps by a modified Stober method and the layer-by-layer (LbL) assembly technique. The obtained bifunctional nanocomposites exhibit superparamagnetic behavior, high fluorescence intensity, and color purity. The architecture has been characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-vis absorption and emission spectroscopy, X-ray diffraction, and superconducting quantum interference device (SQUID) magnetometry.

Deposition of GdVO4 : Eu3+ nanoparticles on silica nanospheres by a simple sol-gel method

The deposition and coating of GdVO4: Eu3+ nanoparticles on spherical silica was carried out using a simple sol - gel method at low temperature. The GdVO4: Eu3+-coated silica composites obtained were characterized by differential thermal analysis (DTA), thermogravimetric (TG) analysis, x-ray diffraction (XRD), Fourier-transform IR spectroscopy (FT-IR), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), photoluminescence spectra, and kinetic decay. It is found that the similar to 5 nm GdVO4: Eu3+ nanoparticles coating the silica spheres are crystal in the as-prepared samples and the crystallinity increases with increasing annealing temperature. The composites obtained are spherical in shape with an average size of 100 nm. The GdVO4: Eu3+ nanoparticles are linked with silica cores by a chemical bond. The photoluminescence spectra of the obtained GdVO4: Eu3+-coated silica composites are similar to those of the bulk GdVO4: Eu3+ phosphors. The strongest peak is near 617 nm, which indicates that Eu3+ is located in the low symmetry site with non-inversion centre.

Non-isothermal crystallisation kinetics of polyamide 6/mesoporous silica nanocomposites

Non-isothermal crystallisation kinetics of a polyamide 6/mesoporous silica nanocomposite (PA6-MS) has been investigated by differential scanning calorimetry (DSC) at different cooling rates. Mandelkern, Jeziorny-Ziabicki and Ozawa methods were applied to describe this crystallisation process. The analyses show that the mesoporous silica particles act as nucleating agents in the composite and that the Avrami exponent n varies from 3.0 to 4.6. The addition of mesoporous silica influenced the mechanism of nucleation and the growth of polyamide 6 (PA6) crystallites.

Synthesis and properties of a novel isomeric polyimide/SiO2 hybrid material

A novel isomeric polyimide/SiO2 hybrid material was successfully prepared through sol-gel technique, and its structure, thermal properties and nano-indenter properties were investigated. First, 3-[(4-phenylethynyl)phthalimide]propyl triethoxysilane (PEIPTES) was successfully synthesized, its structure was characterized by elemental analysis, FT-IR and C-13 NMR. The researches on solubility and thermal properties of PEIPTES show that it can be used for modifying nano-SiO2 precursor. Nano-SiO2 precursor was synthesized by tetraethoxysilane (TECS) through sol-gel technique. Then the PEIPTES solution and the nano-SiO2 precursor were mixed for 6 h to let the PEIPTES molecules react with the nano-SiO2 precursor, and modified nano-SiO2 precursor was obtained. The modified reaction was confirmed by the analyses of FT-IR. At last, isomeric polyimide/SiO2 hybrid material was produced by using isomeric polyimide resin solution and the modified nano-SiO2 precursor after heat treatment process. The structure analysis by SEM indicated that SiO2 particles dispersed in isomeric polyimide matrix homogeneously with nanoscale. Thermogravimetric analyzer, dynamic mechanical thermal analyzer and nano-indenter XP was employed to detect the properties of the materials, the results demonstrated that isomeric polyimide/SiO2 hybrid material has much better thermal properties and nano-indenter properties than those of isomeric polyimide.