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Showing papers on "Thermal decomposition published in 2000"


Journal ArticleDOI
TL;DR: In this paper, the thermal properties of several imidazolium salts were investigated using DSC and TGA/SDTA data, and it was observed that aluminium catalyzes the decomposition of the salts containing the inorganic fluoride anions.

963 citations


Journal ArticleDOI
TL;DR: In the liquefaction process, the micellar-like broken down fragments produced by hydrolysis are degraded to smaller compounds by dehydration, dehydrogenation, deoxygenation and decarboxylation as mentioned in this paper.

904 citations


Journal ArticleDOI
TL;DR: Nickel cobaltite has been synthesized by sol-gel and thermal decomposition techniques and the surface composition studied with Auger (AES) and X-ray photoelectron spectroscopies (XPS) as discussed by the authors.

454 citations


Journal ArticleDOI
TL;DR: In this article, the thermal decomposition of BH3NH3 was studied by thermogravimetry, differential scanning calorimetry (DSC), volumetric measurements and coupled TG/FTIR.

445 citations


Journal ArticleDOI
TL;DR: In this paper, uniform Ag nanowires have been synthesized within nanoscale channels of mesoporous silica SBA-15 by a simple chemical approach, which involves AgNO3 impregnation, followed by thermal decomposition.

348 citations


Journal ArticleDOI
TL;DR: In this paper, the authors showed that the carbon−nitrogen solids have significant sp2 carbon bonding in a conjugated doubly bonded network and showed that these powders have a glassy microstructure with large irregular pores and voids.
Abstract: Nitrogen-rich carbon nitrides are produced as amorphous, bulk solids from the slow thermal decomposition of 2,4,6-triazido-1,3,5-triazine [(C3N3)(N3)3]. This energetic molecular azide is thermally unstable and readily decomposes at 185 °C in a high-pressure reactor to produce carbon nitride materials, e.g., C3N4. Under applied nitrogen gas pressure, (C3N3)(N3)3 decomposes to yield a solid with one of the highest reported nitrogen-to-carbon ratios corresponding to C3N5. This azide precursor also decomposes upon rapid heating to 200 °C to form graphite nanoparticles without any retained nitrogen. Spectroscopic evidence (infrared, nuclear magnetic resonance, and ultraviolet−visible) demonstrates that the carbon−nitrogen solids have significant sp2 carbon bonding in a conjugated doubly bonded network. Electron microscopy reveals that these powders have a glassy microstructure with large irregular pores and voids. C3N4 and C3N5 are thermally stable up to 600 °C and sublime to produce carbon nitride thin films ...

331 citations


Journal ArticleDOI
TL;DR: In this paper, the thermal decomposition pathway of an ultrathin oxide layer on Ge(100) and Si (100) surfaces is examined by synchrotron radiation photoelectron spectroscopy and ultraviolet photo-electron Spectroscopy with helium I radiation.
Abstract: The thermal decomposition pathway of an ultrathin oxide layer on Ge(100) and Si(100) surfaces is examined by synchrotron radiation photoelectron spectroscopy and ultraviolet photoelectron spectroscopy with helium I radiation. The as-prepared oxide layer consists of a mixture of oxides, namely, suboxides and dioxides, on both the surfaces. Upon annealing, the oxide layers decompose and desorb as monoxides. However, we find that the decomposition pathways are different from each other. On annealing Ge oxides, GeO2 species transform to GeO and remain on the surface and desorb at >420 °C. In contrast, annealing of Si oxides results in the transformation of SiO to SiO2 up to temperatures (∼780 °C) close to the desorption. At higher temperatures, SiO2 decomposes and desorbs, implying a reverse transformation to volatile SiO species.

251 citations


Journal ArticleDOI
TL;DR: In this paper, phase transitions and crystal structure modifications were observed during the thermal-desorption decomposition of the alanate NaAlH 4 using in-situ X-ray powder diffraction.

236 citations


Journal ArticleDOI
TL;DR: In this article, the thermodynamic decomposition of polypropylene was studied in the presence of wood flour, lignin, cellulose and charcoal in order to understand the pyrolytic behavior of the mixture of these components occurring in waste.

211 citations


Journal ArticleDOI
TL;DR: In this paper, the catalytic decomposition rate of N2O to N2+ 1 2 O2 in diluted feed streams over Fe/MFI is first order in N 2O.

203 citations


Journal ArticleDOI
TL;DR: The thermal degradation behavior of cellulose fibers and some fibrous cellulose esters with partial degree of substitution has been studied by thermogravimetry analysis (TG) and differential scanning calorimetry (DSC) as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, the synthesis of nano-sized BaTiO3, BaZrO3 and BaTi05Zr05O3 ceramics using alkoxide and semi-alkoxide routes has been investigated and the pervoskites obtained have been compared with respect to crystallisation temperature, crystallite size and compositional purity.
Abstract: Sol-gel synthesis of nano-sized BaTiO3, BaZrO3 and BaTi05Zr05O3 ceramics using alkoxide and semi-alkoxide routes has been investigated and the pervoskites obtained have been compared with respect to crystallisation temperature, crystallite size and compositional purity Heterometal alkoxides containing two (for BaTiO3 and BaZrO3) and three (for BaTi05Zr05O3) different metals were used as single-source precursors in the alkoxide route while semi-alkoxide synthesis was performed by reacting barium hydroxide or acetate with Ti and/or Zr alkoxides Semi-alkoxide synthesis also produces stoichiometric and phase-pure oxides, however, at temperatures higher than 1000°C At temperatures below 1000°C, BaCO3 and small amounts of other undesired phases (eg, BaTi2O4) were present in the oxides derived from semi-alkoxide synthesis Thermal behaviour, studied by TGA/DTA measurements, shows that thermal decomposition occurs in three major steps and depends on the educt composition and the synthesis route Among alkoxide derived powders, crystalline BaTi05Zr05O3 phase is formed at 400°C while complete crystallisation of BaMO3 ceramics occurs around 600°C The cubic to tetragonal phase transition for BaTiO3 is clearly observed at relatively low-temperature of 800°C The stoichiometry and phase homogeneity of the obtained powders were demonstrated by energy dispersive X-ray analysis and powder diffractometry The averaged crystallite size of the obtained nano-ceramics was evaluated using the FormFit programme SEM and TEM observations revealed a high microstructural uniformity

Journal ArticleDOI
TL;DR: In this article, carbonated layered double hydroxides (LDHs) containing Al, Fe, or Cr in a Mg(OH)2 matrix were used as precursors of basic catalysts.

Journal ArticleDOI
TL;DR: In this article, the results of a TPR and XPS investigation of CoxOy-CuO mixed oxides in the range of composition Co : Cu=100:0-8:92 are reported and compared.
Abstract: In this work the results of a TPR and XPS investigation of CoxOy–CuO mixed oxides in the range of composition Co : Cu=100:0–8:92 are reported and compared. The final catalysts were obtained by thermal decomposition in air and N2 at 723 K for 24 h of single‐phase cobalt–copper hydroxycarbonates prepared by coprecipitation at constant pH. The Co : Cu=100 : 0 specimen calcined in air formed the Co2+[Co3]2O4 (Co3O4) spinel phase. The copper‐containing catalysts (Co : Cu=85 : 15–8 : 92) showed mainly two phases: (i) spinels, like Co2+[Co3+]2O4, Co 1-x 2+ Cu x 2+ [Co3+]2O4 and (ii) pure CuO, the relative amount of each phase depending on the Co : Cu atomic ratio. The results of the XPS study are consistent with the bulk findings and revealed the presence of Co2+, Co3+ and Cu2+ species at the catalyst surface. Moreover, the surface quantitative analysis evidenced a cobalt enrichment, in particular for the most diluted cobalt samples. The TPR study showed that the catalyst reduction is affected by a strong mutual influence between cobalt and copper. The reducibility of the mixed oxide catalysts was always promoted with respect to that of the pure Co3O4 and CuO phases and the reduction of cobalt was markedly enhanced by the presence of copper. Cobalt and copper were both reduced to metals regardless of the catalyst composition. On the other hand, the Co : Cu=100 : 0 specimen calcined in N2 formed, as expected, CoO. The initial addition of copper resulted in the formation of the Cu+Co3+O2 compound, besides CoO, up to a Co/Cu=1 atomic ratio at which the CuCoO2 phase was the main component. A further addition of copper led to the formation of CuCoO2 and CuO phases. The XPS results were in good agreement with these findings and the surface quantitative analysis revealed a less enrichment of cobalt with respect to the catalysts calcined in air. The TPR analysis confirmed that the reduction of the N2‐calcined catalysts was also remarkably promoted by the presence of copper. Also in this case cobalt and copper metal were the final products of reduction.

Journal ArticleDOI
TL;DR: In this article, a new scheme of thermal dissociation based on the dissociative evaporation of the reactant with simultaneous condensation of the low-volatile product has been invoked to interpret the kinetics of reduction of FeO, CoO, NiO and Cu2O by carbon.

Journal ArticleDOI
01 Oct 2000-Fuel
TL;DR: In this paper, the thermal decomposition behavior of polypropylene, oil shale and a 1:3 mixture of the two was investigated in a thermogravimetric analyzer (TGA) reaction system in an argon atmosphere.

Journal ArticleDOI
01 Sep 2000-Polymer
TL;DR: In this article, the regenerated Antheraea pernyi silk fibroin films prepared from calcium nitrate solution were treated with 80% aqueous methanol and the thermal and dynamic thermomechanical behaviors of the films were investigated through TGA, DSC and DMTA.

Journal ArticleDOI
TL;DR: In this article, the preparation of polyborosilazanes which are obtained by hydroboration of oligovinylsilazane [−(H 2 CCH)SiHNH−] n with different amounts of H 3 B. SMe 2.
Abstract: This study treats the preparation of polyborosilazanes which are obtained by hydroboration of oligovinylsilazane [–(H 2 CCH)SiHNH–] n with different amounts of H 3 B . SMe 2 . Pyrolysis of these precursors yields amorphous ceramic materials, which only differ in their relative boron content whereas their Si/C/N ratio is very similar. High temperature thermogravimetric analysis reveals that with increasing boron content the material's thermal degradation is shifted toward higher temperatures. Furthermore, the observed mass loss due to nitrogen evaporation during the material's decomposition is noticeably smaller in boron-rich materials than thermodynamically calculated. X-ray diffraction (XRD) experiments support the presence of crystalline silicon nitride in heat treated samples with a minimum boron content of 5 at.%. The decomposition temperature of this phase strongly depends on the amount of boron and can exceed 2000°C. However, high temperature stable materials are not only characterized by a definite B/N ratio, but also by the ability to develop appropriate microstructures.

Journal ArticleDOI
TL;DR: In this article, the thermal decomposition of the complexes Mg(pc)·H 2 O ( I), mg(nc)·3H 2 OD ( II), mgl(nc), 4H 2 OC ( III), mga, ng, 2,6-pyridinedicarboxylate, ac=CH 3 COO − and na=nicotinamide was investigated in an atmosphere of air in the temperature range 20-1000°C by means of TG and DTA.

Journal ArticleDOI
TL;DR: In this article, a simple single-source precursor to stibnite (Sb2S3) synthesized from SbCl3 and thiourea in methanol was characterized.
Abstract: A simple single-source precursor to stibnite (Sb2S3) synthesized from SbCl3 and thiourea in methanol was characterized. The thermal decomposition of the precursor in polar solvents resulted in the formation of one-dimensional Sb2S3 nanocrystallites with the growth direction along the c axis. It is found that the as-prepared Sb2S3 nanorods are formed through the spontaneous connection of adjacent particles. The pressure in the solvothermal process plays an important role in the formation of the nanorods.

Journal ArticleDOI
TL;DR: In this article, the thermal decomposition of transition metal sulphates was studied by thermogravimetry in static air and the TG, DTG and DTA curves were obtained using a Hungarian MOM C-derivatograph.

Journal ArticleDOI
Jin Woo Lee1, Yong Taik Lim1, O Ok Park1
TL;DR: In this paper, the thermal characteristics of two types of organically modified montmorillonite (OMMT) with different alkylammonium cations and their effects upon the formation of polypropylene oligomer (maPP) nanocomposite were examined.
Abstract: We have examined thermal characteristics of two types of organically modified montmorillonite (OMMT) with different alkylammonium cations and their effects upon the formation of PP nanocomposite, when using a maleic anhydride grafted polypropylene oligomer (maPP) as a compatibilizer. The microstructure of the composite has been characterized by X-ray diffraction (XRD) analysis, transmission electron microscopy and Fourier transform infrared spectroscopy. OMMT showed the decrease of the interlayer spacing at the processing temperature, due to the release of organic ion by thermal decomposition. Thermal characteristics of OMMTs depended greatly on the interlayer structure of OMMT. When the OMMT with small interlayer spacing and less organophilicity was used, PP composite resulted in the only partial exfoliation due to thermal decomposition of the clay layers.

Journal ArticleDOI
TL;DR: In this paper, a comparison of the thermal decomposition pathways of ultrathin oxide layers, formed on Ge (100) and Si(100) surfaces, as revealed by photoemission studies, employing synchrotron radiation.

Journal ArticleDOI
TL;DR: In this article, a series of azo metal chelate dyes have been synthesized and the UV-Vis absorption spectra of the azo dye and its metal complexes were measured.

Journal ArticleDOI
TL;DR: In this paper, a new organic nonlinear material for which its solubility in methanol and acetone was found out using the apparatus fabricated by the authors, in order to get the good-quality crystals, methods of evaporation of solvent at room temperature and slow cooling of saturated solution at boiling temperature were adopted.

Journal ArticleDOI
TL;DR: In this paper, the effect of the composition of starting solutions on the phase and chemical composition and the structure of sprayed films is studied, and it was determined that organic phases as products of the thermal decomposition of thiourea ligand are present in the films at all used solution compositions.

Journal ArticleDOI
TL;DR: In this paper, small diamond crystals were crystallized from the starting system of graphite and oxalic acid dihydrate, (COOH) 2 ·2H 2 O, at high pressure and high temperatures of 7.7 GPa and 1400-2000°C, respectively.

Journal ArticleDOI
TL;DR: In this article, Magnesium hydroxide was precipitated from aqueous solution in the form of ultrafine hexagonal tabular particles of about 0.1 μm, and heating this mixture with submicron particles of tabular kaolinite in a molar ratio of MgO·Al 2 O 3 ·2SiO 2 resulted in the formation of an amorphous state at about 900°C after thermal decomposition.

Journal ArticleDOI
TL;DR: In this paper, the authors used XRD, FTIR, ICP/CHN, DTA, TGA, combined TGA-FTIR, HRTEM, and XPS methods to study the decomposition of CoMgAl-hydrotalcite-like compounds.
Abstract: CoMgAl-hydrotalcite-like compounds (CoaMgbAl(OH)c(TA)d·nH2O) intercalated with terephthalate anions ([C6H4(COO)2]2- or TA2-) have been prepared. By using XRD, FTIR, ICP/CHN, DTA, TGA, combined TGA-FTIR, HRTEM, and XPS methods, it has been found that the as-prepared samples undergo different decomposition pathways when they are heated, respectively, in air and in nitrogen atmospheres. In particular, the collapse of the layered structure, i.e., dehydroxylation and the thermal decomposition of TA2- are overlapped within a narrow temperature range (20−30 °C) in air, showing a vigorously exothermic effect. However, the two thermal processes are distinctly separated in N2; each lasts over a rather wide temperature range (100−200 °C). Carbon nanoparticles and short tubules have been produced in the solid state from the intercalated TA2- anions during the decomposition of the hydrotalcite-like compounds in N2. These carbon nanomaterials are multiwalled and close-ended with a diameter of 10−35 nm and a length of 2...

Journal ArticleDOI
TL;DR: In this paper, ammonium persulfate was used as an oxidant in boiling glacial acetic acid for o-phenylenediamine and 2-pyrimidylamine polymers.