Advanced Materials Research Vol. 716

Abstract: In the 0.02 mol/L HCl medium solution, berberine (BB) cationic ion and AuI₂^- combine to BB-AuI₂ association complex molecule. These complex molecules self-aggregate to (BB-AuI₂)_n association particles. It exhibits a fluorescence peaks at 470 nm. A new and sensitive fluorescence method has been proposed for the determination of trace amounts of BB in the range of 10-800 ng/ml. The detection limit is 3ng/ml BB. The method has been applied to the determination of trace berberine in real samples, with satisfactory results. The cause of the fluorescence was also discussed.

Abstract: In the medium of HCl containing KI, acridine red (AR) exhibited a fluorescence peak at 550 nm, and acridine ornage (AO) has a fluorescence peak at 520 nm. Upon addition of IO₃^-, it reacts with excessive I^- to form I₃^-. The AR and I₃^- combine to form an association particle that caused fluorescence quenching at 550 nm. IO₃^- concentration in the range of 5.0-120×10^-7 mol/L can be determined by AR fluorescence quenching method.

Abstract: In acidic condition, NO₂^- combined with p-aminobenzene sulfonic acid by diazotization, and then reacted with α-naphthylamine to form purple azo dye. The resonance Rayleigh scattering (RRS) signal of the color system was detected by nanogold probe. Under the chosen conditions, the decreased RRS intensity ΔI (ΔI= I_b - I) at 500 nm was linear to the NO₂^- concentration in the range of 7.0×10^-2-42.0μmol/L, with a regression equation of ΔI=6.72 C - 6.93, a correlation coefficient of 0.9982 and a detection limit of 2.6×10^-4 mol/L NO₂^-.

Abstract: A new catalytic kinetic method for the determination of vanadium (V) was proposed, based on the V (V) catalyze the slow reaction between KClO₃ and phenylgycollic acid (PA) in 0.6 mol/L H₂SO₄ solution at 100 °C. The reduction product of ClO₃^-, Cl^-, reacts with Ag⁺ to form (AgCl)_n nanoparticles. The nanoparticles exhibit a max resonance scattering spectral peak at 470 nm and a strongest fluorescence peak at 470 nm. The resonance scattering intensity at 470 nm is linear to the V concentration in the range of 2.0×10^-9 mol/L to 4.0×10^-8 mol/L. The influence factors on the catalytic resonance scattering determination of trace vanadium were examined. This catalytic resonance scattering spectral method has been applied to the analysis of vanadium in real samples, with satisfactory results.

Abstract: In 0.08 mol/L HCl medium, berberine (BB) cationic ion and HgI₄^2- combine to BB-HgI₄ association complex molecule. These complex molecules self-aggregate to (BB-HgI₄)_n association particles. It exhibits two fluorescence peaks at 400 nm and 470 nm. A new and sensitive fluorescence method has been proposed for the determination of trace amounts of BB in the range of 10 to 800 ng/mL. The detection limit is 3 ng/mL BB. The method has been applied to the determination of trace berberine in real samples, with satisfactory results. The cause of the fluorescence was also discussed.

Abstract: Pd doped TiO₂ nanoparticles were synthesized by sol-gel method with tetrabutyl titanate and palladium chloride as precursor materials. The products were characterized by XRD, SEM, FTIR and ICPOES technologies. The gas sensing properties of the products to 2-chloroethanol vapor were investigated. The results showed that the optimum concentration of Pd in the TiO₂ nanoparticles was 3 mol% when the particle size of the anatase TiO₂ nanoparticles was about 7 nm. Compared with pure TiO₂ nanoparticles, the 3mol% Pd doped TiO₂ nanoparticles exhibited higher gas sensing activities to 2-chloroethanol vapor.

Abstract: Composite ceramics made of spinel structure NiMn₂O₄ and CaO-doped perovskite structure LaMnO₃ were prepared by a conventional solid state reaction and sintered at different temperatures. The XRD patterns have shown that the major phases presented in the sintered samples are NiMn₂O₄ compounds with the spinel structure, La_1-xCa_xMnO₃ with the perovskite structure and NiO with a monoclinic structure. SEM images show that the density and grain size of the composite ceramics increases with sintered temperature increasing. The electrical resistivity of the composite ceramics at 25°C is found to change significantly depending on the CaO content, while the thermal constant B is still reasonably large in the range of 2400 to 3000 K. For the composition x = 0.1, the composite with a low electrical resistivity (ρ_25°C=4.46Ω·cm) and moderate B value (B_25/50=2762K) was obtained. These composites could be applied as potential candidates for NTC thermistors in the suppression of the inrush current.

Abstract: Catalyst-free InP nanowires were grown on Si (100) and Si (111) substrates by metal organic chemical vapor deposition and the morphology, crystal structure, and optical properties of the nanowires are investigated. X-ray diffraction results show two peaks of InP (111) and InP (220) in the spectra. Two more peaks of InP (200) and InP (311) are observed if PH₃ thermal annealing is performed on the sample for 15 minutes after nanowire growth is completed. The InP (220), InP (311), and InP (200) peaks originate from InP crystal formation on top of the nanowires; only the InP (111) peak originates from the InP nanowires. Finally, the temperature dependence of the PL peak positions of InP nanowires grown on Si (100) and InP substrate are measured.

Abstract: This paper investigated Au-Pd/ZrO₂ alloy catalyst prepared by solution reduction method using NaBH₄ as reducing agent and L-lysine as protection agent. TEM, EDX, XRD, UV-Vis and XPS were employed to investigate the morphology, composition, dispersity and catalytic properties of the catalyst. The results show that Au-Pd/ZrO₂ alloy catalyst is uniform and highly dispersed. Furthermore, this preparation method leads to highly active Au-Pd/ZrO₂ alloy catalyst for the selective oxidation of benzyl alcohol.

Abstract: In this work, reduction of o-hydromandelic acid to o-hydrophenylacetic acid was investigated. Inorganic and metal catalysts were used in the process of reduction to look for a suitable way for transferring o-hydromandelic acid to o-hydrophenylacetic acid. Of all the catalysts, Raney-Ni has the favorable catalytic activity and the orthogonal test was investigated to determine the optimal condition. The yield of o-hydrophenylacetic acid can up to 90%.