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Infrared Fourier Transform Spectroscopy (infrared + fourier_transform_spectroscopy)
Kinds of Infrared Fourier Transform Spectroscopy Selected AbstractsFacile and Reproducible Synthesis of Nanostructured Colloidal ZnO Nanoparticles from Zinc Acetylacetonate: Effect of Experimental Parameters and Mechanistic InvestigationsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 33 2009Alessia Famengo Abstract A facile and reproducible route to nanostructured colloidal ZnO nanoparticles was developed by controlled hydrolysis and condensation of zinc acetylacetonate in alkaline conditions. By reaction of an ethanolic solution of Zn(acac)2 with NaOH in a 1:2 molar ratio, after reflux, ZnO spherical nanoparticles were obtained that displayed a homogeneous size distribution; particle diameters ranged from 6 to 10 nm, as evidenced by transmission electron microscopy (TEM) analysis. The same reaction was carried out also in water, glycerol and 1,2-propanediol, to investigate the effect of the solvent viscosity and dielectric constant on the final features of the obtained material. Irrespective of the nature of the solvent, X-ray diffraction (XRD) analysis shows the formation ofhexagonal ZnO, whereas the presence of residual unreacted Zn(acac)2 could be ruled out. Indeed, different particle sizes and very different morphologies were obtained. Also the reflux step was shown to be a key factor in avoiding the fast precipitation of a floc and achieving a pure compound, which was isolated and thoroughly characterised. The composition of the obtained ZnO was determined by elemental analysis, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), showing the formation of pure ZnO. IR spectroscopy evidenced the presence of adsorbed organic ligands on the colloid surfaces. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) revealed the presence of medium- to high-strength acidic sites on the ZnO surface. To gain a deeper insight into the formation mechanisms of these nanostructures, time-resolved UV/Vis and XAS studies were performed on the ethanol solution used for the synthesis of the oxide and also on the solid specimen, obtained after the refluxing step. No remarkable changes could be evidenced in the solution after the addition of an understoichiometric amount of NaOH, but the growth of the ZnO nanoparticles could be followed by UV/Vis spectra. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Dye,fiber interactions in PET fibers: Hydrogen bonding studied by IR-spectroscopyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Karen De Clerck Abstract Dye,fiber interactions are studied in poly (ethylene terephthalate) fibers by FT-IR spectroscopy. It is shown for the first time that DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) serves as an easy applicable and accurate technique for the study of fibrous structures. This article focuses on the possible hydrogen bond interactions in the dye,fiber system, where the PET fibers are dyed with anthraquinone-based disperse dyes. The dyes and related anthraquinone structures are studied in both the dilute solution state, the solid state, and as present in the PET fibers. It is proven that 1-amino anthraquinones show strong "chelate-type" intramolecular hydrogen bonding in all three states. In the fibers an important supplementary intermolecular hydrogen bonding with the CO groups in the PET fiber is observed. The extend of hydrogen bonding seems to be prone to dye concentration variations. Further analysis by modulated differential scanning calorimetry links the hydrogen bonding to an intrinsic plasticizing effect of the dyes affecting the dye diffusion process. This thus offers a tool for the fundamental understanding of the dyeing process and possible observed differences in dyeing behavior in dye,fiber systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Structure, texture and surface acidity studies of a series of mixed zinc,aluminum (60,90 molar % Al) phosphate catalystsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2001Karim Mtalsi Abstract A series of mixed zinc,aluminum phosphate (ZnAlP) catalysts containing 40,90 aluminum molar % were synthesized by a coprecipitation method and characterized by nitrogen adsorption,desorption, X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature programmed desorption (TPD) of ammonia. The presence of aluminum greatly affected the surface properties of Zn3(PO4)2 by delaying the crystallization process of Zn3(PO4)2. All amorphous samples were shown to be mesoporous and they contained two types of aluminum surface hydroxyl groups and one type of phosphorus hydroxyl group, as shown by DRIFT spectra. The specific surface area and the acidity of ZnAlP increased on increasing the aluminum content. On the other hand, a great difference in the texture and the concentration of surface acid sites was found by changing the precipitating agent and calcination temperature. Thus these factors also play an important role in the final properties of these catalysts. © 2001 Society of Chemical Industry [source] Systematic Approach for Dispersion of Silicon Nitride Powder in Organic Media: I, Surface Chemistry of the PowderJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2000Liwu Wang To develop novel dispersants for submicrometer-sized Si3N4 powder, the surface chemistry of a powder has been investigated using thermodesorption, carrier-gas heat extraction, X-ray photoelectron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and zeta potential measurements. This study indicates that the powder surface is composed mainly of silanol groups and exhibits acidic behavior. Furthermore, the interaction affinity of various surface probe molecules with the powder surface has been studied using adsorption isotherms. The detailed description of the surface chemistry can be used as a guide for designing efficient dispersants, as will be presented in part II. [source] Dispersing silicon nanoparticles in a stirred media mill , investigating the evolution of morphology, structure and oxide formationPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2007A. Reindl Abstract Silicon nanoparticles were dispersed for 24 hours in 1-butanol using a stirred media mill. Via this process intrinsically stable suspensions (in regard to aggregation) of Si nanoparticles were produced after 6 hours of dispersing. The evolution of morphology, particle size and structure was investigated by dynamic light scattering, X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy as a function of dispersing time. The average crystallite size decreased from about 18 nm down to about 10 nm within 24 hours of milling as determined by X-ray diffraction and Raman scattering measurements. In addition careful analysis of the Raman spectra revealed a decrease of the crystalline volume fraction from 75% down to 24% and a corresponding increase of the amorphous phase. The microstructural development with varying crystallite size and crystalline volume fraction was directly confirmed by transmission electron microscopy measurements. Elemental analysis showed an increase of oxygen content that was directly proportional to the increase in specific surface area of the silicon nanoparticles during the dispersing process. The surface chemistry of the Si nanoparticles was analyzed by diffuse reflectance infrared Fourier transform spectroscopy that indicated vibrational bands of HSi,Si3,xOx, SiOx, and residual 1-butanol. The final product of the dispersing process seems to be a two-phase mixture of amorphous Si and Si nanocrystallites covered with SiOx on the surface. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Specific binding of a biotinylated, metallocarbonyl-labelled dendrimer to immobilized avidin detected by diffuse-reflectance infrared Fourier transform spectroscopyAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2004Bogna Rudolf Abstract Molecular recognition between avidin covalently immobilized at the surface of acrylic resin beads and a transition metallocarbonyl tracer of the biotin ligand was detected using diffuse reflectance infrared Fourier transform spectroscopy. Copyright © 2004 John Wiley & Sons, Ltd. [source] The Synthesis of ZrO2/SiO2 Nanocomposites by the Two-Step CVD of a Volatile Halogen-Free Zr Alkoxide in a Fluidized-Bed Reactor,CHEMICAL VAPOR DEPOSITION, Issue 1 2007W. Xia Abstract ZrO2/SiO2 nanocomposites with Zr loadings in the range 0.88 wt,% to 12.2 wt,% were prepared by a two-step metal-organic (MO)CVD process in a fluidized-bed reactor with the Zr alkoxide [Zr(OiPr)2(tbaoac)2] as the precursor. The high surface area of silica was hardly diminished by the deposition, and the deposited zirconia species were highly dispersed, as indicated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) investigations. The XPS data reveal a linear increase of the Zr surface concentration with increasing Zr loading. The high degree of dispersion is attributed to a strong interaction between the zirconia species and the support through the formation of Si-O-Zr bonds. Correspondingly, the intensity of the isolated silanol bands detected by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was found to decrease with increasing Zr loading. [source] Catalytic Properties of Nanoscale Iron-Doped Zirconia Solid-Solution Aerogels,CHEMPHYSCHEM, Issue 7 2008Lifang Chen Abstract Nanoscale iron-doped zirconia solid-solution aerogels are prepared via a simple ethanol thermal route using zirconyl nitrate and iron nitrate as starting materials, followed by a supercritical fluid drying process. Structural characteristics are investigated by means of powder X-ray diffraction (XRD), thermal analyses (TG/DTA), N2 adsorption measurements and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results show that the resulting iron-doped solid solutions are metastable tetragonal zirconia which exhibit excellent dispersibility and high solubility of iron oxide. Further, when the Fe:(Fe+Zr) ratio x is lower than 0.10, all of the Fe3+ ions can be incorporated into ZrO2 by substituting Zr4+ to form Zr1,xFexOy solid solutions. Moreover, for the first time, an additional hydroxyl group band that is not present in pure ZrO2 is observed by DRIFTS for the Zr(Fe)O2 solid solution. This is direct evidence of Fe3+ ions incorporated into ZrO2. These Zr1,xFexOy solid solutions are excellent catalysts for the solvent-free aerobic oxidation of n -hexadecane using air as the oxidant under ambient conditions. The Zr0.8Fe0.2Oy solid-solution catalyst demonstrates the best catalytic properties, with the conversion of n -hexadecane reaching 36.2,% with 48,% selectivity for ketones and 24,% selectivity for alcohols and it can be recycled five times without significant loss of activity. [source] Investigation of mineral composition of oil shaleASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Dong-Mei Wang Abstract The aim of this paper is to identify the mineral composition of oil shale from different locations and relate it to their interval of occurrence. Thermogravimetric analysis (TGA), diffuse reflectance infrared Fourier transforms spectroscopy (DRIFTS) and X-ray diffraction (XRD) methods were used for this invetigation. Hydrogen peroxide was used as the oxidant to eliminate the influence of organic matter in TGA. DRIFTS results indicated that most of the kerogen is in aliphatic hydrocarbon form and the peak of hydrocarbon nearly disappeared after oxidation. XRD results indicated that quartz, muscovite, kaolinite and calcite are the dominant minerals. Longkou and Changchun oil shale samples contain high percentage of calcite (12.9 and 11.7% CO2 respectively) while Fushun and Huadian oil shale samples contain less than 6% CO2. Especially, in Fushun oil shale sample, the content is below 3%. Kaolinite is found in Fushun oil shale sample, while muscovite is only found in Huadian oil shale sample. Integration of the XRD, DRIFTS and TGA results of the oil shale samples from different locations has provided a better way of mineral composition identification. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | |||||||||||||