Preparation of Gold Microcrystal-Doped TiO2, ZrO2 and Al2O3 Films Through Sol-Gel Process

Au-microcrystal-doped TiO₂, ZrO₂ and Al₂O₃ films were made by sol-gel dip-coating method using titanium, zirconium and aluminum alkoxides with HAuCl₄ · 4H₂O. The influence of the oxide matrix composition on the maximum amount of the Au microcrystals that can be incorporated in the oxide film was examined. Some amount of Au microcrystals were exhausted to the surface of Au microcrystal-doped oxide films when an excess amount of HAuCl₄ · 4H₂O was dissolved in the coating solution. The maximum amount of Au that can be incorporated in the oxide film was found to increase with the increase of the pH point at zero charge (PZC) of the matrix oxide. This should be due to the fact that AuCl ₄ ^- ions are charged negative and also Au microcrystals tend to charge negative, so that the oxide gel with high PZC, which has a tendency to charge positive, may fix the ions and/or microcrystals to its interior. A maximum amount of Au microcrystals as high as 12.6 vol% was attained in an Au:Al₂O₃ film.     

Preparation of Au-TiO2 Hybrid Nano Particles in Silicate Film Made by Sol-Gel Method

TiO₂ nano particles with photo catalytic property were mixed with silica alkoxides solution with HAuCl₄/4H₂O. STS02 (purchased from Ishihara Sangyo Kaisha, Ltd.) was used as TiO₂ nano particles. The average size of TiO₂ nano particles was 7 nm in diameter. The gel film coated on glass substrate was heated and then HAuCl₄/4H₂O was thermally reduced at 390 degree. The coated silica gel film doped with HAuCl₄/4H₂O and TiO₂ nano particles was turned into light blue from colorless gel film after heat treatment. The optical absorption spectrum showed the absorption peak of the film heated at 390 degree shifted to at about 650 nm compare to SiO₂ film doped with Au nano particles without TiO₂ nano particles that had absorption peak at 542 nm. On the other hand, the film formed from coating solution incorporated TiAA (titanium tetraisopropoxide chelated by acetyl acetone) as TiO₂ source instead of TiO₂ nano particles had absorption peak at 550 nm. That means there was no effect on formation of Au nano particles when TiAA was incorporated. The average size of the particles was found to be about 23 nm in diameter by TEM observation. Furthermore EDX (Energy Dispersive X-ray Fluorescence Spectrometer) analysis of nano particles in the film indicated that Au-TiO₂ nano hybrid particles were formed. Simulation results also supported that the size in diameter of Au nano particles had little influence on the absorption coefficient of the silica film doped with Au nano particles.     

Direct growth of comet-like superstructures of Au-ZnO submicron rod arrays by solvothermal soft chemistry process

The synthesis, characterization and proposed growth process of a new kind of comet-like Au-ZnO superstructures are described here. This Au-ZnO superstructure was directly created by a simple and mild solvothermal reaction, dissolving the reactants of zinc acetate dihydrate and hydrogen tetrachloroaurate tetrahydrate (HAuCl₄·4H₂O) in ethylenediamine and taking advantage of the lattice matching growth between definitized ZnO plane and Au plane and the natural growth habit of the ZnO rods along [001] direction in solutions. For a typical comet-like Au-ZnO superstructure, its comet head consists of one hemispherical end of a central thick ZnO rod and an outer Au-ZnO thin layer, and its comet tail consists of radially standing ZnO submicron rod arrays growing on the Au-ZnO thin layer. These ZnO rods have diameters in range of 0.2-0.5 μm, an average aspect ratio of about 10, and lengths of up to about 4 μm. The morphology, size and structure of the ZnO superstructures are dependent on the concentration of reactants and the reaction time. The HAuCl₄·4H₂O plays a key role for the solvothermal growth of the comet-like superstructure, and only are ZnO fibers obtained in absence of the HAuCl₄·4H₂O. The UV-vis absorption spectrum shows two absorptions at 365-390 nm and 480-600 nm, respectively attributing to the characteristic of the ZnO wide-band semiconductor material and the surface plasmon resonance of the Au particles.     

Preparation of Forsterite (Mg2SiO4) Powders Via an Aqueous Route Using Magnesium Salts and Silicon Tetrachloride (SiCl4)

Forsterite (Mg₂SiO₄) powders were prepared by mixing SiCl₄ with aqueous solutions of either Mg(CH₃COO)₂·4H₂O or Mg(NO₃)₂·6H₂O and heating the powdered gel. The powders were characterised using thermal analysis (DTA and TGA), X-ray diffraction (XRD), nitrogen adsorption surface area analysis (BET) and transmission electron microscopy (TEM). On heating, MgO and enstatite (MgSiO₃) were observed in addition to forsterite. On heating to 1200°C, forsterite was the dominant phase in the powders produced from Mg(NO₃)₂·6H₂O, and MgO was the dominant phase in the powders produced from Mg(CH₃COO)₂·4H₂O. The primary particle sizes of these powders were between 100 and 500 nm, which remained the same on heat treatment. However, higher temperatures gave rise to an increase in the size and densities of the agglomerates of primary particles.     

Metal Oxide Thin Films Containing Au Nano-Particles Prepared with Gas Diffusion Method

Au particles dispersed thin metal oxide films were prepared from precursor films containing HAuCl₄ with H₂S gas diffusion method. HAuCl₄ was uniformly dissolved in the films as promoted by hydroxypropyl cellulose (HPC). The mechanism of the Au particle formation was studied. It was found that HAuCl₄ was converted directly to Au metal particles upon contacting with H₂S gas. Au particles generated by this method were characterized with small particle size, sharp size distribution and high volume fraction in the films. The surface plasma resonance absorption of Au particles shifted to longer wavelength when TiO₂ component was introduced in the matrix.     

Control of optical properties of gel-derived oxide coating films containing fine metal particles

Control of the optical properties of gel-derived oxide films containing fine metal particles is described. The duration of the aging of Si(OC₂H₅)₄-derived sols and the amount of water for hydrolyzing Si(OC₂H₅)₄ were found to greatly affect the size and the shape of Au particles formed in the silica matrix, and accordingly the optical absorption of the Au/SiO₂ composite films. Employing dielectric media with high refractive indices like TiO₂ was shown to shift the absorption peak of Au particles to longer wavelengths. Pd/TiO₂ and Pt/TiO₂ composite films showed absorption in the visible region.     

The effect of carrier solution on the particle size distribution of inorganic colloids measured by steric field-flow fractionation

The number average and the weight average particle diameters for suspended inorganic colloids found by the new technique of steric field-flow fractionation may be successfully used provided that the most suitable carrier solution is selected, in order to minimize the coagulation and adhesion phenomena.In the present work polydisperse, irregular colloidal particles of FePO₄·2H₂O (strengite) were studied. The average particle diameters were found to vary with the electrolyte concentration in the suspending medium. A strong variation of the number and weight average particle diameters was also observed with the quantity of the surfactant added to aquatic medium in order to increase colloidal stability. The influence of the electrokinetic charge of the FePO₄·2H₂O particles in relation to the surface charge of the material of the column employed, on the particle size measured was investigated. The proper carrier solution for minimizing coagulation and adhesion phenomena in the FePO₄·2H₂O colloidal particles was found to contain either 1.5% (v/v) detergent FL-70 and 0.1 MKNO₃ or 0.5% (v/v) detergent FL-70 and 0.033 MNa₂SO₄.     

Aqueous solubilities of praseodymium,europium, and lutetium sulfates

The aqueous solubilities of finely divided Pr₂(SO₄)₃·8H₂O(cr), Eu₂(SO₄)₃·8H₂O(cr), and Lu₂(SO₄)₃·8H₂O(cr) have been measured as a function of time at 25°C using isothermal saturation. Solubilities of the latter two salts showed a steady decrease with time, whereas Pr₂(SO₄)₃·8H₂O(cr) showed no such variation within the accuracy of the determinations. The turbidities of these filtered saturated solutions also decreased with time, and indicate that some colloidal rare earth sulfates were present. These colloidal particles (<0.2 m) have a large surface area, which contributes to the Gibbs energy of the solid phase, thus giving rise to enhanced solubilities. The micro-particles also grow with time, thereby reducing the surface area contribution to the Gibbs energy and also leaving fewer particles to pass through the filters. Extrapolation of solubilities to infinite time gives the solubilities of macrocurstalline Eu₂(SO₄)₃·8H₂O and Lu₂(SO₄)₃·8H₂O. Previous solubility data for Lu₂(SO₄)₃, at 20 and 40°C, yield an interpolated value at 25°C that is about 30% low. Densities were also measured at several concentrations of each salt.     

The First VOPO4·2H2O Intercalation Compound Synthesized through a Solid-State Reaction at Room Temperature

This communication reports the first intercalation into VOPO₄·2H₂O performed through a solid-state reaction at room temperature. Ethyleneurea, EU (2-imidazolidone) was intercalated into the oxovanadium phosphate by grinding in a mortar stoichiometric amounts of both reagents at room temperature for 30 min. C, H and N elemental analyses of the obtained intercalation compound gave the formula VOPO₄·(EU)·H₂O. The profile of the absorption bands due to the VOPO₄ lattice vibration around 1000 cm⁻¹ was retained after reaction, providing evidence that an intercalation compound and not merely a salt of V-P-O species was produced. For α-VOPO₄·2H₂O, the interlayer distance is 0.75 nm, whereas for the EU inter-calation compound it is 0.95 nm. The obtained SEM micrographs show that the microstructure of VOPO₄·2H₂O is changed after reaction, with a total exfoliation of the oxovanadium matrix.     

Zr 改性MnOx/MWCNTs催化剂的结构特征与低温SCR活性

以ZrO（NO₃）₂·2H₂O为前驱体对多壁碳纳米管（MWCNTs）进行了改性并负载MnO_x制备了MnO_x/ZrO₂/MWCNTs 催化剂. 考察了Zr 对催化剂低温选择性催化还原（SCR）反应活性的影响,并通过多种分析手段对催化剂的结构进行了表征. 结果表明Zr 的添加对催化剂的低温SCR活性具有显著的促进作用,当Zr 负载量为30%时,催化剂活性最佳. X射线衍射（XRD）、拉曼（Raman）光谱、透射电镜（TEM）、N₂吸附-脱附的表征结果分析表明,适量的Zr 改性促进了MnO_x在载体表面的分散,增强金属氧化物与MWCNTs 之间的作用,也能增加催化剂的比表面积、孔容和孔径. X 射线光电子能谱（XPS）、H₂程序升温还原（H₂-TPR）和NH₃程序升温脱附（NH₃-TPD）的分析结果则显示,Zr 能提高催化剂表面化学吸附氧浓度,促进Mn³⁺转化为Mn⁴⁺,从而使催化剂表面的活性位点增多,氧化还原能力增强,同时还提高了催化剂表面酸性位点的数量和强度,促进了NH₃的吸附,是MnO_x/ZrO₂/MWCNTs 催化剂低温SCR活性提高的主要原因.     

Extraction systems of flame atomic absorption determination of trace impurities in high purity nickel salts

Summary Different extraction sytems including long chain quaternary alkylammonium salts and APDC were investigated in order to determine the optimal conditions for extraction separation and preconcentration of traces of Ag, Bi, Cd, Cu, Fe, Mo, Pb, Sb and Zn from high purity NiSO₄·6H₂O, NiCl₂·6H₂O, Ni(OOCCH₃)₂·4H₂O and Ni(NO)₃)₂·6 H₂O. Best results for multielement preconcentration were found with the extraction system HCl-trioctylmethylammonium chloride-0,002 mol/l APDC/MIBK. The proposed method permits the flame atomic absorption determination of 5·10^–6%, Ag, Cd, Cu and Zn, 1·10^–5% Bi, Fe, Pb and 5·10^–5% Mo and Sb with good accuracy and precision.     

Au/ZrO2催化CO氧化反应中ZrO2纳米粒子的尺寸效应

从同一ZrO(OH)₂出发制备了三种不同尺寸的ZrO₂纳米颗粒(ZrO₂-CP: 40～200 nm, ZrO₂-AN: 18～25 nm, ZrO₂-AD: 10～15 nm), 采用沉积-沉淀方法制备了相应的Au/ZrO₂催化剂. 用XRD, XRF, TEM和低温N₂吸附对ZrO₂和Au/ZrO₂进行了表征. XRD和TEM分析表明Au/ZrO₂样品中Au粒子的平均尺寸为4～5 nm, 而ZrO₂的晶相和颗粒大小没有因为“负载”Au粒子而发生变化. CO催化氧化反应的结果表明, Au/ZrO₂催化活性随着ZrO₂纳米粒子尺寸的减小活性明显增加. TEM/HRTEM结果表明, Au/ZrO₂催化剂中Au粒子与ZrO₂颗粒接触界面随ZrO₂颗粒尺寸的减小而明显增加, 这很可能是含有更小尺寸ZrO₂纳米粒子的Au/ZrO₂催化剂具有更高催化活性的重要原因.     

Gamma radiation induced synthesis of gold nanoparticles in aqueous polyvinyl pyrrolidone solution and its application for hydrogen peroxide estimation

Gold nanoparticles (Au nps) have been synthesized in aqueous solution of polyvinyl pyrrolidone (PVP) by gamma radiolysis from HAuCl₄·3H₂O precursor and in presence of small concentrations of Ag⁺, 2-propanol and acetone. The effect of different experimental parameters, such as concentration of reactant, molecular weight of PVP on nanoparticle formation was studied. TEM image confirmed that spherical Au nps were formed when PVP of molecular weight 360,000 Da was used as capping agent. H₂O₂ is a reactant in the enzyme catalyzed reaction of o-phenylene diamine (o-PDA). The reaction product has a weak absorption in the yellow region of the spectrum. When this product interacts with Au nps, it leads to enhancement of the absorption peak. The nanoparticles synthesized by radiation method were used for estimation of H₂O₂. The absorbance value of this peak at λ_max was observed to change with H₂O₂ concentration, which was monitored for estimation of H₂O₂. The response is linear in the range of 2.5×10⁻⁶ mol dm⁻³ to 2×10⁻⁴ mol dm⁻³ and 1×10⁻⁷ mol dm⁻³ to 3×10⁻⁶ mol dm⁻³ H₂O₂ in two separate sets of experimental parameters with detection limit 1×10⁻⁷ mol dm⁻³.     

Zur Kenntnis der Kupferphosphate

Among the sparingly soluble copper(II)-phophates the existence of CuHPO₄·H₂O and of Cu₄H(PO₄)₃·3 H₂O was verified by X-ray powder-diagrams, other statements on preparations and X-ray diagrams were corrected. Cu₃(PO₄)₂·3 H₂O apparently does not exist. Structural analogies of Cu₄H(PO₄)₃·3 H₂O and CaHPO₄·2 H₂O may offer an explanation for the restraint hydrolysis of the calcium salt in presence of low copper concentrations. Pseudomalachite was synthesised hydrothermally.     

Chemie der Seltenerdmetalle, 20. Mitt.: Yttriumtartrate im neutralen und alkalischen Bereich

Zusammenfassung Es wurden die Verbindungen HYT ^*·4 H₂O, Y₄ T ₃·14 H₂O, LiYT·4 H₂O, NaYT·5 H₂O, KYT·3 H₂O, RbYT·4 H₂O, CsYT·4 H₂O, NH₄YT·3 H₂O, K₂YTOH·4 H₂O, K₃YT(OH)₂·4 H₂O, K₄YT(OH)₃·3 H₂O, K₅YT(OH)₄·3 H₂O, KYH₄ T ₂·3 H₂O, K₂YH₃ T ₂·5 H₂O, K₃YH₂ T ₂·4 H₂O, KY₂ T(OH)₃·5 H₂O, K₂Y₂ T(OH)₄·5 H₂O isoliert. Die Präparate wurden mit Hilfe von Thermoanalyse, IR-Absorptionsspektren und Röntgenstreuung näher charakterisiert und ihre Löslichkeit in Wasser untersucht.

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Some complexes of Yttrium with tartrates were isolated and the compounds characterised by thermogravimetric analysis, IR-spectroscopy and X-ray diffraction. Solubility in water was examined.

     

Lanthantartrate im neutralen und alkalischen Bereich

Zusammenfassung Die Substanzen LaHT ^*·4 H₂O, La₄ T ₃·14 H₂O, KLaT· ·3 H₂O, K₂LaTOH·4 H₂O, K₂LaH₃ T ₂·4 H₂O, K₃LaH₂ T ₂· ·4 H₂O und K₄LaHT ₂·5 H₂O wurden isoliert und durch Thermoanalyse, IR-Absorptionspektren und Röntgenstreuung näher charakterisiert. Es wurde auch ihre Löslichkeit in Wasser bestimmt.

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The following compounds where isolated, and characterized by means of thermal analysis, I. R. spectroscopy and X-ray diffraction. Their solubilities in aqueous solution were determined: LaHT·4 H₂O, La₄ T ₃·14 H₂O, KLaT·3 H₂O, K₂LaTOH· ·4 H₂O, K₂LaH₃ T ₂·4 H₂O, K₃LaH₂ T ₂·4 H₂O, K₄LaHT ₂· ·5 H₂O.

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Mit 7 Abbildungen     

Film-Forming Capacity of Sn(II), Zr(IV), and Hf(IV) Acetylacetonates

Zr(acac)₄, Hf(acac)₄, and SnHacacCl₂ · 2H₂O were prepared in the solid state and in enthanol solutions. The film-forming capacity and thermal stability of these compounds were studied. Films of ZrO₂, HfO₂, and SnO₂ were prepared from film-forming solutions of the corresponding acetylacetonates.     

Direkte Bestimmung der Additivelemente Ca, Ba und Zn in Schmier?len

Zusammenfassung Lösungen von CaCl₂ · 2 H₂O, BaCl₂ · 2 H₂O und Zn(CH₃CO₂)₂ · 2 H₂O in Dimethylsulfoxid lassen sich anstelle metallorganischer Verbindungen als Standards zur direkten Bestimmung der Additivelemente Ca, Ba und Zn in Schmierölen mittels Atomabsorptionsspektroskopie verwenden. In 10 verschiedenen Ölen wurden die Additive bestimmt. Die mit Atomabsorption erhaltenen Meßergebnisse weichen von den naßchemisch ermittelten um maximal 5% ab.

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Direct determination of the additive elements Ca, Ba and Zn in lubricating oilsSolutions of inorganic salts in dimethyl sulphoxide as standards in atomic absorption spectroscopy

For the determination of the additive elements Ca, Ba and Zn in oils by atomic absorption spectroscopy, solutions of CaCl₂ · 2 H₂O, BaCl₂ · 2 H₂O and Zn(CH₃CO₂)₂ · 2 H₂O in dimethyl sulphoxide can be used as standards instead of metallorganic compounds. The additives in 10 different oil samples have been determined. The results obtained by atomic absorption differ from those gained by conventional analytical methods by 5% at most.

     

Water vapor pressure and thermodynamics of dehydration of Group 2 perchlorate hydrates

The limits of existence for Group 2 perchlorate hydrates are defined. The water vapor pressure is measured over the crystal hydrates Mg(ClO₄)₂·2H₂O, Ca(ClO_{4 2}·4H₂O, Sr(ClO₄)₂·3H₂O, Sr(ClO₄)₂·2H₂O, Sr(ClO₄)₂·H₂O, Ba(ClO₄)₂·3H₂O, and Ba(ClO₄)₂·H₂O. The water vapor pressure and thermodynamics constants of dehydration depend directly on the electron-acceptor strength of the cation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1467–1473, July, 1990.     

Synthesis and Properties of Acidic 3d-Metal Urates

Acidic urates [Mn(HL)₂] · H₂O, [FeOH(HL)₂]₂ · 4H₂O, [Co(HL)₂(H₂O)₂] · 2H₂O, and [Ni(HL)₂(H₂O)₂] · 2H₂O (H₂L is uric acid) were synthesized and their structures and physicochemical properties were studied using IR spectroscopy, diffuse reflection spectroscopy, DTA, and magnetochemistry methods. The metals were shown to coordinate the urate anion through oxygen and nitrogen atoms. The [FeOH(HL)₂]₂ · 4H₂O complex has a dimeric structure.