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.

Direct electron transfer and electrocatalysis of glucose oxidase immobilized on glassy carbon electrode modified with Nafion and mesoporous carbon FDU-15

In this paper, it was found that glucose oxidase (GOD) has been stably immobilized on glassy carbon electrode modified with mesoporous carbon FDU-15 (MC-FDU-15) and Nafion by simple technique. The sorption behavior of GOD immobilized on MC-FDU-15 matrix was characterized by transmission electron microscopy (TEM), ultraviolet-visible (UV-vis), FTIR, respectively, which demonstrated that MC-FDU-15 could facilitate the electron exchange between the active center of GOD and electrode. The direct electrochemistry and electrocatalysis behavior of GOD on the modified electrode were characterized by cyclic voltammogram (CV) which indicated that GOD immobilized on Nafion and MC-FDU-15 matrices display direct, reversible and surface-controlled redox reaction with an enhanced electron transfer rate constant of 4.095 s(-1) in 0.1 M phosphate buffer solution (PBS) (pH 7.12).

Direct electrochemistry and electrocatalysis of glucose oxidase immobilized on glassy carbon electrode modified by Nafion and ordered mesoporous silica-SBA-15

In this paper, it was found that glucose oxidase (GOD) has been stably immobilized on glassy carbon electrode modified by ordered mesoporous silica-SBA-15 and Nafion. The sorption behavior of GOD immobilized on SBA-15 matrix was characterized by transmission electron microscopy (TEM), ultraviolet-visible (UV-vis), FTIR, respectively, which demonstrated that SBA-15 can facilitate the electron exchange between the electroactive center of GOD and electrode. The direct electrochemistry and electrocatalysis behavior of GOD on modified electrode were characterized by cyclic voltammogram (CV) which indicated that GOD immobilized on Nafion and SBA-15 matrices displays direct, nearly reversible and surface-controlled redox reaction with an enhanced electron transfer rate constant of 3.89 s(-1) in 0.1 M phosphate buffer solution (PBS) (pH 7.12).

Synthesis and characterization of magnetic FexOy@SBA-15 composites with different morphologies for controlled drug release and targeting

Magnetic functionalization of the ordered mesoporous SBA-15 (SiO2) aggregate blocks and rice grain-like particles were realized by using a sol-gel method, resulting in the formation of FexOy@SBA-15 composite materials. The X-ray diffraction (XRD), N-2 adsorption/desorption, and transmission electron microscopy (TEM) results show that these composites conserved ordered mesoporous structure after the formation of FexOy nanoparticles in the pores and on the outer surface of SBA-15. It was confirmed by the XRD and X-ray photoelectron spectroscopy (XPS) analysis that the FexOy generated in these mesoporous silica hosts is mainly composed of gamma-Fe2O3. Magnetic measurements reveal that these composites possess superparamagnetic properties at 300 K. The saturation magnetization of these composites increased with the increasing loading amount of gamma-Fe2O3. These composites, which possess high surface area and high pore volume, show magnetic response sufficient for drug targeting in the presence of an external magnetic field.

Host-sensitized luminescence of Dy3+, Pr3+, Tb3+ in polycrystalline SrIn2O4 for field emission displays

SrIn2O4:Dy3+/Pr3+/Tb3+ white/red/green phosphors were prepared by the Pechini sol-gel process. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), diffuse reflectance, photoluminescence, cathodoluminescence spectra, and lifetimes were utilized to characterize the samples. XRD reveal that the samples begin to crystallize at 800 degrees C and pure SrIn2O4 phase can be obtained at 900 degrees C. FE-SEM images indicate that the SrIn2O4:Dy3+, SrIn2O4:Pr3+, and SrIn2O4:Tb3+ samples consist of fine and spherical grains with size around 200-400 nm. Under the excitation of ultraviolet light and low-voltage electron beams (1 - 5 kV), the SrIn2O4:Dy3+, SrIn2O4: Pr3+, and SrIn2O4: Tb3+ phosphors show the characteristic emissions of Dy3+ (F-4(9/2) - H-6(15/2) at 492 nm and 4F(9/2) - 6H(13/2) at 581 nm, near white), Pr3+ (P-3(0) - H-3(4) at 493 nm, D-1(2) - H-3(4) at 606 nm, and P-3(0) - H-3(6) at 617 nm, red) and Tb3+ (D-5(4) - F-7(6,5,4,3) transitions dominated by D-5(4) - F-7(5) at 544 nm, green), respectively. All of the luminescence resulted from an efficient energy transfer from the SrIn2O4 host lattice to the doped Dy3+, Pr3+, and Tb3+ ions, and the luminescence mechanisms have been proposed.

有序介孔材料SBA-15吸附Ru(bpy)_3~(2+)修饰电极的电化学发光研究

制备了具有高比表面积且二维六方高度有序的介孔分子筛SBA-15,并采用TEM和氮气吸附实验对其结构性质进行了表征.利用静电作用将三联吡啶钌[Ru(bpy)32+]固定到表面带负电荷的SBA-15上,并将吸附有Ru(bpy)32+的SBA-15修饰到玻碳电极表面,研究了该固定化的Ru(bpy)32+的电化学发光行为.结果表明,随着三丙胺(TPA)的加入,氧化电流增加而还原电流减小,表明TPA对三价吡啶钌有催化作用,同时TPA的加入显著增强了发光强度.随着扫描速率的增加,发光强度逐渐降低.SBA-15较大的孔径和开放交联的孔结构体系促进了电极表面膜内的物质扩散和电子运动扩散.该修饰电极在5.0×10-5~1.0×10-2mol/LTPA浓度范围内,发光强度与浓度具有良好的线性关系,线性方程为y=71.7+41.2x,检出限为9.5×10-6mol/L.该电极在连续扫描下具有较好的稳定性.

Assembly of 12-tungstosilicic acid and 4-aminobenzo-15-crown-5 ether based on the electrostatic attraction through bridging of oxonium ions on different substrates

Based on the electrostatic attraction Keggin-type polyoxometalate H4SiW12O40 (SiW12) and small molecule 4-aminobenzo-15-crown-5 ether (4-AB15C5) were alternately deposited on poly (allylamine hydrochloride) (PAH)-derived indium tin oxide (ITO) substrate through a layer-by-layer (LBL) self-assembly, forming a supramolecular multilayer film (film-A). SiW12 was also deposited on a glassy carbon electrode (GCE) derived by 4-AB15C5 via covalent bonding in 0.1 M NaCl aqueous solution and formed a composite monolayer film (film-B). UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy measurements demonstrated that the interactions between SiW12 and 4-AB15C5 in both two film electrodes were the same and caused by the bridging action of oxonium ions. But, the nanostructure in the two film electrodes was different. 4-AB15C5 in film-A was oriented horizontally to ITO substrate, however, that in film-B was oriented vertically to GCE. Namely film-A corresponded to a layer structure, and film-B corresponded to an intercalation structure.

Solvent effects on spectrophotometric titrations and vibrational spectroscopy of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin in aqueoius DMF

The spectrophotometric titration by sodium hydroxide of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin ((OH)(1)PH2) is studied as a function of solvent composition of DMF-H2O binary solvent mixture ([OH-] = 0.04 M). Combining the structure changes of the porphyrin and the "four orbital" model of Gouterman, many features of the optical spectra of this deprotonated para-hydroxy-substituted tetraphenylporphyrin in different composition of binary solvent mixtures can be rationalized. In highly aqueous solvents, the changes of the titration curves are shown to be mainly due to hydrogen-bonding of the oxygen of the phenoxide anion group by the hydroxylic solvent, Which decreases the energy of the phenoxide anion pi orbital. Thus the phenoxide anion pi orbital cannot cross over the porphyrin Tr orbital being a different HOMO. However, its energy is close to that of the porphyrin pi orbitals. As a result, in the visible region, no charge-transfer band is observed, while in the visible-near region, the Soret peak split into two components. In nonaqueous solvents, the changes are mainly attributed to further deprotonation of pyrrolic-Hs of (OH) 1PH2 by NaOH and coordination with two sodium ions to form the sodium complex of (OH) 1PH2, which turns hyperporphyrin spectra of deprotonated of phenolic-H of (OH)(1)PH2 into three-banded spectra of regular metalloporphyrin.

Phase diagram data for several salt plus salt aqueous biphasic systems at 298.15 K

Phase diagrams corresponding to aqueous biphasic systems of salt (the organic ionic liquid of salts [C(4)mim]Cl, [C(6)mim]Cl, and [C(8)mim]Cl) + salt (K3PO4, K2CO3) + water were determined at 298.15 K. The binodal curve was fitted to the Merchuk equation. Tie lines assigned from mass phase ratios according to the lever arm rule were satisfactorily described using the Othmer-Tobias and Bancroft equations.

One-step synthesis of palladium/SBA-15 nanocomposites and its catalytic application

Well-dispersed palladium nanoparticles in mesoporous SBA- 15 SiO2 were prepared in a facile one-step approach during sol-gel route under reductive atmosphere. X-ray diffraction (XRD) results indicate that as-synthesized nanocomposites basically remain ordered two-dimensional hexagonal mesostructure while transmission electron microscopy (TEM) study exhibits a well dispersion of palladium nanoparticles within the mesoporous SBA-15 channels. The size of Pd nanoparticles is approximately in the range of 5-10nm. However, the resulting nanocomposites exhibit a highly catalytic activity and reused ability at least after five recycles without ligand in air for both the Suzuki and Heck coupling reactions.

Novel heteroleptic Cu-I complexes with tunable emission color for efficient phosphorescent light-emitting diodes

A series of orange-red to red phosphorescent heteroleptic Cu-I complexes (the first ligand: 2,2 '-biquinoline (bq), 4,4 '-diphenyl2,2 '-biquinoline (dpbq) or 3,3 '-methylen-4,4 '-diphenyl-2,2 '-biquinoline (mdpbq); the second ligand: triphenylphosphine or bis[2-(diphenylphosphino)phenyl]ether (DPEphos)) have been synthesized and fully characterized. With highly rigid bulky biquinoline-type ligands, complexes [Cu(mdpbq)(PPh3)(2)](BF4) and [Cu(mdpbq)(DPEphos)](BF4) emit efficiently in 20 wt % PMMA films with photoluminescence quantum yield of 0.56 and 0.43 and emission maximum of 606 nm and 617 nm, respectively. By doping these complexes in poly(vinyl carbazole) (PVK) or N-(4-(carbazol-9-yl)phenyl)-3,6-bis(carbazol-9-yl) carbazole (TCCz), phosphorescent organic light-emitting diodes (OLEDs) were fabricated with various device structures. The complex [Cu(mdpbq)(DPEphos)](BF4) exhibits the best device performance. With the device structure of ITO/PEDOT/ TCCz:[Cu(mdpbq)(DPEphos)](BF4) (15 wt %)/TPBI/LiF/Al (III), a current efficiency up to 6.4 cd A(-1) with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.61, 0.39) has been realized. To our best knowledge, this is the first report of efficient mononuclear Cu complexes with red emission.

Facilitated ion-transfer of sodium cation by (anthraquinone-1-yloxy) methane-15-crown-5 across the water/1,2-dichloroethane microinterface

The transfer of sodium cation facilitated by (anthraquinone-1-yloxy) methane-15-crown-5(L) has been investigated at the water/1,2-dichloroethane microinterface supported at the tip of a micropipette. The diffusion coefficient of (anthraquinone-1-yloxy) methane-15-crown-5 obtained was (3.42 +/- 0.20) x 10(-6) cm(2) s(-1). The steady-state voltammograms were observed for forward and backward scans due to sodium ion transfer facilitated by L with 1:1 stoichiometry. The mechanism corresponded to an interfacial complexation (TIC) and interfacial dissociation (TID) process. The association constant was calculated to be log beta(o) = 11.08 +/- 0.03 in the DCE phase. The association constant of other alkali metals (Li+, K+, Rb+) were also obtained.

Low threshold amplified spontaneous emission based on coumarin 151 encapsulated in mesoporous SBA-15

Amplified spontaneous emission (ASE) characteristics of a blue dye coumarin 151 encapsulated in a highly ordered mesoporous SBA-15 were studied. The spectra narrowing was observed and found that the threshold and loss were greatly reduced, and the gain is significantly increased compared with spin-coated coumarin 151 doped poly(4-vinylphenol) film. The ASE threshold, gain, and loss, respectively, reached 0.55 mJ pulse(-1) cm(-2), 44.78 cm(-1), and 8.9 cm(-1) for the coumarin 151 encapsulated in mesoporous SBA-15 film. The optimized lasing action owes much to the effects of the better spatial confinement of the molecules in the ordered mesoporous structure of the host SBA-15.

Covalent linking of near-infrared luminescent ternary lanthanide (Er3+, Nd3+, Yb3+) complexes on functionalized mesoporous MCM-41 and SBA-15

The near-infrared (NIR) luminescent lanthanide ions, such as Er(III), Nd(III), and Yb(III), have been paid much attention for the potential use in the optical communications or laser systems. For the first time, the NIR-luminescent Ln(dbm)(3)phen complexes have been covalently bonded to the ordered mesoporous materials MCM-41 and SBA-15 via a functionalized phen group phen-Si (phen-Si = 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline; dbm = dibenzoylmethanate; Ln = Er, Nd, Yb). The synthesis parameters X = 12 and Y = 6 h (X denotes Ln(dbM)(3)(H2O)(2)/phen-MCM-41 molar ratio or Ln(dbM)(3)(H2O)(2)/phenSBA-15 molar ratio and Y is the reaction time for the ligand exchange reaction; phen-MCM-41 and phenSBA-15 are phen-functionalized MCM-41 and SBA-15 mesoporous materials, respectively) were selected through a systematic and comparative study. The derivative materials, denoted as Ln(dbM)(3)phen-MCM-41 and Ln(dbm)(3)phen-SBA-15 (Ln = Er, Nd, Yb), were characterized by powder X-ray diffraction, nitrogen adsorption/desorption, Fourier transform infrared (FT-IR), elemental analysis, and fluorescence spectra. Upon excitation of the ligands absorption bands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide ions through the intramolecular energy transfer from the ligands to the lanthanide ions.