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The structural studies of aluminosilicate gels and thin films synthesized by the sol-gel method using different Al2O3 and SiO2 precursors

Abstract

Aluminosilicate materials were obtained by sol-gel method, using different Al2O3 and SiO2 precursors in order to prepare sols based on water and organic solvents. As SiO2 precursors, Aerosil 200TM and tetraethoxysilane TEOS: Si(OC2H5)4 were applied, while DisperalTM and aluminium secondary butoxide ATSB: Al(OC4H9)3 were used for Al2O3 ones. Bulk samples were obtained by heating gels at 500 °C, 850 °C and at 1150 °C in air, while thin films were synthesized on carbon, steel and alundum (representing porous ceramics) substrates by the dip coating method. Thin films were annealed in air (steel and alundum) and in argon (carbon) at different temperatures, depending on the substrate type. The samples were synthesized as gels and coatings of the composition corresponding the that of 3Al2O3·2SiO2 mullite because of the specific valuable properties of this material. The structure of the annealed bulk samples and coatings was studied by FT-IR spectroscopy and XRD method (in standard and GID configurations). Additionally, the electron microscopy (SEM) together with EDS microanalysis were applied to describe the morphology and the chemical composition of thin films. The analysis of FT-IR spectra and X-ray diffraction patterns of bulk samples revealed the presence of γ-Al2O3 and δ-Al2O3 phases, together with the small amount of SiO2 in the particulate samples. This observation was confirmed by the bands due to vibrations of Al–O bonds occurring in γ-Al2O3 and δ-Al2O3 structures, in the range of 400 to 900 cm−1. The same phases (γ-Al2O3 and δ-Al2O) were observed in the deposited coatings, but the presence of particulate ones strongly depended on the type of Al2O3 and SiO2 precursor and on the heat treatment temperature. All thin films contained considerable amounts of amorphous phase.

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Studies on rheological, structural, optical, electrical and surface properties of LiMn2O4 thin films by varied spin rates

Abstract

LiMn2O4 thin films prepared by cost-effective spin coating method using optimized coating conditions are reported. Spin rate was varied and spin rate dependent properties were studied. Prepared films were characterized for their structural, morphological and optical properties. X-ray diffraction study of LiMn2O4 thin films confirmed the cubic spinel structure with the preferred orientation along (1 1 1) plane. Optical absorption studies showed band gap energy of 3.02 eV for the grown LiMn2O4 films. FT-IR bands assigned to asymmetric stretching modes of MnO6 group were located around 623 cm-1 and 514 cm-1 for the LiMn2O4 thin films. The weak band observed at 437 cm-1 was attributed to the LiO4 tetrahedra. The films showed high conductivity value 0.79 S/cm indicating the generation of effective network of the film for enhanced charge transport. AFM micrographs of the LiMn2O4 films deposited at 3000 rpm and 3500 rpm showed uniform distribution of fine grains throughout the surface without any dark pits, pinholes and cracks.

Open access
Application of Anaerobic Digestate as Inoculum for Treatment of the Plant-Derived Wastes: Case Study

.06.002 [10] J. De Vrieze, L. Raport, B. Willems, S. Verbrugge, E. Volcke, E. Meers, L. T. Angenent, and N. Boon, “Inoculum selection influences the biochemical methane potential of agro-industrial substrates,” Microbial Biotechnology , vol. 8, no. 5, pp. 776–786, Mar. 2015. https://doi.org/10.1111/1751-7915.12268 [11] S. Tandy, J. R. Healey, M. A. Nason, J. C. Williamson, D. L. Jones, and S. C. Thain, “FT-IR as an alternative method for measuring chemical properties during composting,” Bioresource Technology , vol. 101, no. 14, pp. 5431–5436, Jul. 2010. https

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Application of Fourier Transform Infra-red Evolved Gas Analysis (FT-IR-EGA) to the Study of Tobacco Curing

References 1. Lephardt, J. O., and R. A. Fenner: Characterization of pyrolysis and combustion of complex systems using Fourier transform infrared spectroscopy; Appl. Spectrosc. 34 (1980) 174—185. 2. Lephardt, J, O., and R. A. Fenner: Fourier transform infrared evolved gas analysis — Additional considerations and options; Appl. Spectrosc. 35 (1980) 95—101. 3. Lephardt, J. O.: Fourier transform infrared evolved gas analysis (FT-IR-EGA); Appl, Spectrosc. Rev. 18 (1982-3) 265

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Morphology and FT IR spectra of porous silicon

), 475709. [9] M. J. Sailor and E. J. Lee, “Surface Chemistry of Luminescent Silicon Nanocrystallites”, Advanced Materials , vol. 9, no. 10 (1997), 783–793. [10] C. Q. Lai, W. Zheng, W. K. Choi and C. V. Thompson, “Metal Assisted Anodic Etching of Silicon”, Nanoscale , vol. 7 (2015), 11123–11134. [11] Z. H. Wang, T. Urisu, H. Watanabe, K. Ooi, G. R. Rao, S. Nanbu, J. Maki and M. Aoyagi, “Assignment of Surface IR Absorption Spectra Observed the Oxidation Reactions: 2H + H 2 O/Si(100) and H 2 O + H/Si(100)”, Surface Science , vol. 57, no. 5 (2005) 330

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Phase, microstructure and dielectric properties of 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 ceramics prepared by sol-gel technique

Abstract

0.94Bi0.5Na0.5TiO3-0.06BaTiO3 ceramics were fabricated by sol-gel technique. The XRD results revealed the formation of a single phase perovskite structured Bi0.5Na0.5TiO3-BaTiO3 at 600 °C. The SEM images showed dense microstructure and the optimum density of the ceramics sintered at 1100 °C was 5.2 g/cm3. The saturation polarization (Ps) was found to be increased with increasing temperature while the remnant polarization (Pr) was found to be increased gradually and then decreased abruptly near 85 °C, which could be attributed to the phase transformation. The coercive electric field (Ec) was found to be decreased gradually with increasing temperature. The maximum value of dielectric constant (ɛ r) at room temperature was 800 and dielectric loss at 1 MHz was 0.07.

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Structural, non-linear optical and dielectric properties of LPAHCl-manganese sulphate and cadmium chloride co-crystals

Abstract

Co-crystals of L-phenylalanine hydrochloride (LPAHCl) were grown by slow evaporation technique in the presence of manganese sulphate and cadmium chloride. Crystallinity of the grown crystals was confirmed by single crystal X-ray diffraction. Optical transmission spectra showed very high transmittance in the entire visible region. The cut-off wavelength was observed at 250 nm for both the crystals. The optical band gap energy was found to be 4.37 eV and 4.31 eV for the grown co-crystals of LPAHCl with MnSO4 and CdCl2, respectively. The second harmonic generation of the grown crystals was confirmed by Kurtz and Perry powder SHG method and compared with KDP. The frequency dependent dielectric properties of the co-crystals were studied at different temperatures.

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Low-temperature synthesis of zeolite from perlite waste — Part I: review of methods and phase compositions of resulting products

.E., Chem. Commun., (1996), 1205. [35] Dwyer J., Millward D., O’MALLEY P.J., Araya A., Corma A., Fornes V., Martinez A., J. Chem. Soc., Faraday Trans., 86/6 (1990), 1001. http://dx.doi.org/10.1039/ft9908601001 [36] Novembre D., di Sabatino B., Gimeno D., Pace C., Clay Miner., 46 (2011), 339. http://dx.doi.org/10.1180/claymin.2011.046.3.339 [37] Fernández-Jiménez A., Palomo A., Micropor. Mesopor. Mat., 86 (2005), 207. http://dx.doi.org/10.1016/j.micromeso.2005

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The utilization of copper/zeolite as catalyst in the microwave-assisted synthesis of some novel sulfonamide derivatives

Abstract

Zeolite Y clay modified copper nitrate catalyst was prepared. The obtained catalyst was analyzed by SEM, EDS, and powder XRD techniques. The zeolite Y clay modified copper nitrate catalyst was used for the synthesis of various substituted mesalazine by sulfonylation. The synthesized sulfonamides have been characterized by GC-MS, IR, 1H, 13C and HSQC NMR techniques. The yield percentages of sulfonamides are more than 85%.

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Influence of the B-site cation nature on crystal structure and magnetic properties of Ca2BMoO6 (B = Cr, La, Sm) double perovskite

6 and Ca2MnWO6: a neutron diffraction study. J. Phys. Condens. Mat. 2002, 14, 38, 8817-8830. 15. Lavat, A. E., Baran, E. J. IR-spectroscopic characterization of A2BB’O6 perovskites. Vib. Spectrosc. A. 2003, 32, 167-174. 16. Martinez-Lope, M. J., Alonso, J. A., Casais, M. T., Garcia-Hernandez, M., Pomjakushin, V. Preparation, structural study from neutron diffraction data and magnetism of the disordered perovskite Ca(Cr0.5Mo0.5)O3. J. Solid State Chem. 2006, 179 ,8, 2506-2510

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