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The effect of supports on coke deposition on supported platinum and platinum-tin catalysts investigated by FT-IR spectroscopy

The effect of supports on coke deposition on supported platinum and platinum-tin catalysts investigated by FT-IR spectroscopy

Coke deposit is produced from ethylene on the surface of the platinum and platinum-tin catalysts supported on two various Al2 O3, SiO2 and SiO2 -Al2O3. The coke amount and the structure depend on the type and the amount of the components introduced onto the catalyst support and on the type of the support. It has been found that the surface area of the support has no significant effect on the type of species in the coke deposit. The analysis of the FT-IR spectra has shown the presence of different species on the surface of the catalysts, including carboxyl groups, pseudo-graphite (polyaromatic) structures, polyphenylene groups, acetyl groups, carbonyl groups of acetone and formate type, enol species.

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Changes in Structure and Content Humic Substances in Soil During the Laboratory Simulated Fires

, M.D. (2004): Elemental compositions, FT-IR spectra and thermal behavior of sedimentary fulvic and humic acids from aquatic and terrestrial environments. Geochemical Journal , 38, p. 255–264. GLASS, D.W.; JOHNSON, D.W.; BLANK, R.R.; MILLER, W.W. (2008): Factors affecting mineral nitrogen transformation by soil heating: a laboratory – simulated fire study. Soil Science , 173, 6, p. 387–400. GONZÁLEZ-PÉREZ, J.A.; GONZÁLEZ-VILA, F.J.; ALMENDROS, G.; KNICKER, H. (2004): The effect of fire on soil organic matter – a review. Environment International 30

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Comparison of methods for the identification and sub-typing of O157 and non-O157 Escherichia coli serotypes and their integration into a polyphasic taxonomy approach

bacteria to utilise 95 various carbon sources and assigns unknown strains to a species by mathematically comparing their utilisation pattern (metabolic fingerprint) with the Biolog database ( Odumeru et al ., 1999 ; Kootallur et al ., 2011 ). Fourier transform-infrared (FT-IR) spectroscopy is considered a chemotaxonomic method that is able to provide a great amount of taxonomic data. Spectra obtained from cellular biomass are very characteristic and can be considered as ‘fingerprints’ or molecular patterns distinctive of a particular bacterial strain ( Naumann, 2000

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Influence of river floods on the humification process in the bottom sediments from the Goczałkowice reservoir

study of humic acids isolated from sediments and soils, Senckenbergiana maritima , 32, 1–2, pp. 183–189. Giovela, M., Parlanti, E., Soriano-Sierra, E.J., Soldi, M.S. & Sierrae, M.M.D. (2004). Elemental compositions, FT-IR spectra and thermal behavior of sedimentary fulvic and humic acids from aquatic and terrestrial environments, Geochemical Journal , 38, pp. 255–264. Godlewska, M., Mazurkiewicz-Boro, G., Pociecha, A., Wilk-Woźniak, E. & Jelonek, M. (2003). Effects of flood on the functioning of the Dobczyce Reservoir ecosystem, Hydrobiologia , 504, pp

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Effect of cerium on structural and optical properties of ZnO aerogel synthesized in supercritical methanol

spontaneously to room temperature. The obtained powders were characterized without any chemical or heating treatments. The crystalline structure of the as-prepared aerogels was studied using a PANalytical diffractometer where the X-rays are produced from a radiation source CuKα (λ= 1.54 Å), with an acceleration voltage of 40 kV and a current of 30 mA. Infrared spectra (FT-IR) were recorded with a Shimadzu’s IRAffinity-1 spectrometer by KBr pellet technique. SEM images were obtained with a JSM-840A JEOL microscope type. UV spectra were recorded at room temperature with a

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Physicochemical Characterization Of The Multiuse Medical Textiles In Surgery And As Packaging Material In Medical Sterilization

., Qian, G. (2009). Analysis of the chemical composition of cotton seed coat by Fourier-transform infrared (FT-IR) microspectroscopy. Cellulose, 16, 1099-1107. DOI 10.1007/s10570-009-9349-2 [16] Edwards, H. G. M., Farwell, D. W., Webster, D. (1997). FT Raman microscopy of untreated natural plant fibres. Spectrochimica Acta Part A, 53, 2383-2392.

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Structural and magnetic studies on Co-Zn nanoferrite synthesized via sol-gel and combustion methods

Abstract

Co–Zn nanocrystalline ferrites with chemical composition Co0:5Zn0:5Fe2O4 were synthesized by sol-gel and combustion methods. The sol-gel method was carried out in two ways, i.e. based on chelating agents PVA and PEG of high and low molecular weights. In auto-combustion method, the ratio of citric acid to metal nitrate was taken as 1:1, while in sol-gel method the chelating agents were taken based on oxygen balance. All the three samples were studied by thermogravimetric and differential thermal analysis for the identification of phase formation and ferritization temperature. The synthesized samples were characterized by powder X-ray diffraction and FT-IR spectroscopy without any thermal treatment. The measured lattice constants and observed characteristic IR absorption bands of the three samples are in good agreement with the reported values showing the formation of a cubic spinel structure. The crystallite sizes of all samples were determined using high intensity peaks and W-H plot. Size-Strain Plot method was also implemented since two of the samples showed low crystallite sizes. The least crystallite size (5.5 nm) was observed for the sample CZVP while the highest (23.8 nm) was observed for the sample CZCA. Cation distribution was proposed based on calculated and observed intensity ratios of selected planes from X ray diffraction data. All structural parameters were presented using experimental lattice constant and oxygen positional parameter, and they correlated with FT-IR results. Magnetic measurements were carried out using vibrating sample magnetometer at room temperature to obtain the characteristic parameters such as saturation magnetization, coercivity, remanence, squareness ratio and Bohr magnetons. Among all, the sample synthesized via citric acid autocombustion method displayed a remarkably higher magnetization of 53 emu/g and the remaining two samples displayed low magnetization values owing to their smaller crystallite sizes.

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FT-IR/PAS Study of Surface EDTA-ZnO Interactions

Abstract

The interaction of EDTA disodium salt with zinc oxide was investigated by photoacoustic (PA) FT-IR. It was demonstrated that EDTA-III adsorbs on ZnO, and the process mimics behaviour of EDTA-oxide systems, in which IEPS of oxide catalytic supports is higher than 9. Model of the interaction, described in literature, was discussed.

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Effect of magnesium substitution on structural and dielectric properties of LiNiPO4

addition [ 12 – 15 ]. This paper deals with the synthesis and characterization of LiNi 1–x Mg x PO 4 (x = 0, 0.05, 0.1 and 0.15) obtained by solid state reaction method. The materials were characterized for phase purity and cation environment by X-ray diffraction. Fourier transform infrared (FT-IR) spectroscopy was used to study the local order. Electrical properties were studied by impedance spectroscopy. The structural and conductivity studies of the substituted phases were discussed in comparison with LiNiPO 4 . 2 Experimental The cathode compositions

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Structural and optical characteristics of SnS thin film prepared by SILAR

Abstract

SnS thin films were grown on glass substrates by a simple route named successive ion layer adsorption and reaction (SILAR) method. The films were prepared using tin chloride as tin (Sn) source and ammonium sulfide as sulphur (S) source. The structural, optical and morphological study was done using XRD, FESEM, FT-IR and UV-Vis spectrophotometer. XRD measurement confirmed the presence of orthorhombic phase. Particle size estimated from XRD was about 45 nm which fitted well with the FESEM measurement. The value of band gap was about 1.63 eV indicating that SnS can be used as an important material for thin film solar cells. The surface morphology showed a smooth, homogenous film over the substrate. Characteristic stretching vibration mode of SnS was observed in the absorption band of FT-IR spectrum. The electrical activation energy was about 0.306 eV.

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