scispace - formally typeset
Search or ask a question

Showing papers on "Thermal decomposition published in 2006"


Journal ArticleDOI
TL;DR: Upconverting lanthanide-doped nanocrystals were synthesized via the thermal decomposition of trifluoroacetate precursors in a mixture of oleic acid and octadecene to provide highly luminescent nanoparticles through a simple one-pot technique with only one preparatory step.
Abstract: Upconverting lanthanide-doped nanocrystals were synthesized via the thermal decomposition of trifluoroacetate precursors in a mixture of oleic acid and octadecene. This method provides highly luminescent nanoparticles through a simple one-pot technique with only one preparatory step. The Er3+, Yb3+ and Tm3+, Yb3+ doped cubic NaYF4 nanocrystals are colloidally stable in nonpolar organic solvents and exhibit green/red and blue upconversion luminescence, respectively, under 977 nm laser excitation with low power densities.

955 citations


Journal ArticleDOI
TL;DR: In this article, the authors summarize literature data on thermal decomposition of ammonium perchlorate and discuss the mechanism of the decomposition and various factors that influence the thermal decompositions of perchlorates.

492 citations


Journal ArticleDOI
TL;DR: Monodisperse Fe nanoparticles are synthesized via a simple one-pot thermal decomposition of Fe(CO)5 in the presence of oleylamine and are suitable for biomolecule attachment and biomedical applications.
Abstract: Monodisperse Fe nanoparticles are synthesized via a simple one-pot thermal decomposition of Fe(CO)5 in the presence of oleylamine. Controlled oxidation of the iron surface leads to crystalline Fe3O4 shell and results in dramatic increase of chemical and dispersion stability of the nanoparticles. Surface ligand exchange is readily applied to transfer the core/shell nanoparticles from hydrophobic to hydrophilic, and a stable aqueous nanoparticle dispersion in PBS is formed. The functionalized nanoparticles are suitable for biomolecule attachment and biomedical applications.

491 citations


Journal ArticleDOI
08 Dec 2006-Polymer
TL;DR: In this paper, a systematic and comparative evaluation of the pyrolysis of halogen-free flame-retarded epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (phosphorus contents around 2.6 wt%) and the fire behavior of their carbon fiber composites is presented.

379 citations


Journal ArticleDOI
TL;DR: Magnetite nanoparticles (Fe3O4) of three different sizes below the limit for single domain magnetic behaviour have been obtained by thermal decomposition of an iron precursor in an organic medium in the presence of a surfactant.
Abstract: Magnetite nanoparticles (Fe3O4) of three different sizes below the limit for single domain magnetic behaviour have been obtained by thermal decomposition of an iron precursor in an organic medium in the presence of a surfactant. Good agreement between mean particle size obtained by TEM, crystal size calculated from x-ray diffraction and magnetic diameter calculated from magnetization curves measured at room temperature shows that the samples consist of uniform, crystalline and isolated magnetite nanoparticles with sizes between 5 and 11 nm. High saturation magnetization and high initial susceptibility values have been found, the latter decreasing as the particle size decreases. The main contribution to the anisotropy is magnetocrystalline and shape anisotropy, since surface anisotropy is suppressed by the oleic acid molecules which are covalently bonded to the nanoparticle surface.

337 citations


Journal ArticleDOI
TL;DR: In this paper, a gas phase process of single-walled carbon nanotube (SWCNT) formation, based on thermal decomposition of iron pentacarbonyl or ferrocene in the presence of carbon monoxide (CO), was investigated in ambient pressure laminar flow reactors in the temperature range of 600-1300 ǫ.

301 citations


Journal ArticleDOI
TL;DR: An assessment of the mechanisms and kinetics of pyrite transformation in inert and oxygen-containing atmospheres at elevated temperatures has been performed based on a literature review in this paper.

261 citations


Journal ArticleDOI
TL;DR: It is found that nearly monodisperse copper oxide nanoparticles prepared via the thermal decomposition of a Cu(I) precursor exhibit exceptional activity toward CO oxidation in CO/O2/N2 mixtures.
Abstract: We find that nearly monodisperse copper oxide nanoparticles prepared via the thermal decomposition of a Cu(I) precursor exhibit exceptional activity toward CO oxidation in CO/O2/N2 mixtures. Greater than 99.5% conversion of CO to CO2 could be achieved at temperatures less than 250 degrees C for over 12 h. In addition, the phase diagram and pathway for CO oxidation on Cu2O (100) is computed by ab initio methods and found to be in qualitative agreement with the experimental findings.

260 citations


Journal ArticleDOI
TL;DR: In this paper, the dissolution of a metallic precursor in a supercritical fluid and the exposure of a substrate to the solution is used to reduce the precursor to its metal form by a wide variety of methods resulting in films or particles.
Abstract: Supercritical fluids (SCFs) have been used to deposit thin metal films onto a wide range of surfaces and incorporate metallic particles into different inorganic and organic substrates for microelectronic, optical and catalytic applications. The technique involves the dissolution of a metallic precursor in a SCF and the exposure of a substrate to the solution. After incorporation of the precursor with the substrate, the metallic precursor is reduced to its metal form by a wide variety of methods resulting in films or particles. The reduction methods employed are chemical reduction in the SCF with a reducing agent, such as hydrogen and alcohols, thermal reduction in the SCF and thermal decomposition in an inert atmosphere or chemical conversion with hydrogen or air. Both highly dispersed and uniformly distributed metal crystallites (

242 citations


Journal ArticleDOI
TL;DR: The long term thermal stability of ionic liquids containing dicyanamide or tricyanomethide anions is significantly lower than might be expected from temperature ramped TGA studies, and these anions, combined with N-based cations, yield polymeric products during thermal decomposition.

221 citations


Journal ArticleDOI
TL;DR: In this article, the thermal decomposition behavior of poly(N-vinyl-2-pyrrolidone) (PVP) on platinum (Pt) is investigated.
Abstract: TG-DTA, TEM, and IR were used to investigate the thermal decomposition behavior of poly(N-vinyl-2-pyrrolidone) (PVP). The TG-DTA results show that the thermal decomposition behavior of PVP on platinum (Pt) is quite different from that of pure PVP. For pure PVP, 95.25% is decomposed when the temperature is increased up to 500°C; while under the same experimental condition, PVP coated on the Pt nanoparticles is only 66.7% decomposed. This is further supported by IR measurement. TEM results exhibited that the partially decomposed PVP still plays a role in stabilizing Pt nanoparticles: after heating treatment at 500°C for half an hour, the platinum nanoparticles did not aggregate heavily. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 23–26, 2006

Journal ArticleDOI
TL;DR: In this article, the synthesis and characterization of nanocrystalline ZnO powders by a simple method using zinc acetate dihydrate and polyvinyl pyrrolidone (PVP) as a chelating agent was reported.

Journal ArticleDOI
TL;DR: In this article, single-walled carbon nanotube (SWNT) and polyvinylidene fluoride (PVDF) composites were fabricated by dispersion of SWNT in an aqueous surfactant solution, followed by mixing with PVDF powder, filtration and hot pressing.
Abstract: Single-walled carbon nanotube (SWNT)–poly(vinylidene fluoride) (PVDF) composites were fabricated by dispersion of SWNT in an aqueous surfactant solution, followed by mixing with PVDF powder, filtration and hot pressing. The thermal properties of the composites at various SWNT volume fraction up to 49% were investigated. The coefficient of thermal expansion (CTE) was decreased with increase of the SWNT content. The thermal conductivity increased with temperature in the temperature range from 25 to 150 °C. The thermal conductivity was enhanced, but not up to the level required by heat sink applications. The melting point was not affected significantly by the addition of SWNT, but the degree of crystallinity was increased and the decomposition temperature of the matrix was decreased. The large number of junctions among SWNT largely offsets the benefit of the high thermal conductivity of SWNT. In addition, the impurity and defects in SWNT are believed to limit the thermal conductivity of the composites. Lastly, the reduced thermal stability of the composite compared to the matrix might result from the presence of the metal catalyst contained in the SWNT.

Journal ArticleDOI
Jiang Li1, Yubai Pan1, Changshu Xiang1, Qiming Ge1, Jingkun Guo1 
TL;DR: In this paper, a simple aqueous sol-gel method using a citrate polymeric precursor derived from aluminum nitrate and citric acid mixed solution was used to synthesize ultrafine α-Al 2 O 3.

Journal ArticleDOI
TL;DR: In this article, the synthesis of N-doped single-walled carbon nanotubes (N-SWNTs) via the thermal decomposition of ferrocene/ethanol/benzylamine (FEB) solutions in an Ar atmosphere at 950 °C was described.

Journal ArticleDOI
TL;DR: In this paper, the authors report the preparation and electrochemical performance of an ordered mesoporous β-MnO2 as a positive electrode for rechargeable lithium batteries, and the correlation between the specific mesopore structure and the superior performance was discussed in detail.
Abstract: The highly crystallized β-MnO2 with the narrowest [1 × 1] channels prepared by direct thermal decomposition of Mn(NO3)2 does not provide much capacity due to the poor kinetics of the lithium intercalation/deintercalation process. In the present work, we report the preparation and electrochemical performance of an ordered mesoporous β-MnO2 as a positive electrode for rechargeable lithium batteries. The well-ordered mesoporous β-MnO2 prepared using mesoporous silica KIT-6 as a template by thermal decomposition of Mn(NO3)2 exhibits high initial capacity, reaching a chemical composition of Li0.75MnO2, and it also shows a good rate capability and cycling ability. The correlation between the specific mesoporous structure and the superior electrochemical performance was discussed in detail.

Journal ArticleDOI
TL;DR: In this article, surface modified zinc oxide nanoparticles (ZnO) in methyl methacrylate (MMA) were used to improve the free radical bulk polymerization process as well as the thermal stability of the formed polymer.
Abstract: Summary: Dispersing surface-modified zinc oxide nanoparticles (ZnO) in methyl methacrylate (MMA) improves the free radical bulk polymerization process as well as the thermal stability of the formed polymer. Hydroxy groups available on the ZnO surface may induce a degenerative transfer. This suppresses the gel effect, which leads to a better control of the heat evolution during the late stages of polymerization. The formation of chains having vinylidene end groups and head-to-head links is suppressed, which shifts the onset of thermal decomposition to the regime where decomposition occurs by random chain scission.

Journal ArticleDOI
TL;DR: In this paper, the reduction of stored NO x with hydrogen was analyzed over model Ba/ γ -Al 2 O 3 and Pt-Ba/Al 2O 3 LNT trap catalysts.

Journal ArticleDOI
TL;DR: 1,1-diamino-2,2-dinitroethylene has been synthesised by treatment of acetamidinium chloride with diethylmalonate to obtain 2-methyl-pyrimidine-4,6-dione which on nitration followed by hydrolysis gave FOX-7.

Journal ArticleDOI
TL;DR: In this paper, thermogravimetric/mass spectrometric (TG/MS) analysis of straight rubber elastomers and tire parts was performed by using DTG curves of tire parts.

Journal ArticleDOI
TL;DR: Nickel oxide nanorings were synthesized by controllable thermal decomposition of precursor Ni(OH)(2) nanoplates obtained via the reaction between Ni(NO(3))·6H(2)O and NaOH under hydrothermal conditions.
Abstract: Nickel oxide (NiO) nanorings were synthesized by controllable thermal decomposition of precursor Ni(OH)2 nanoplates obtained via the reaction between Ni(NO3)·6H2O and NaOH under hydrothermal conditions. The process of their formation was investigated and an unexpected catalytic property of this novel-shaped material is reported for CO oxidation.

Journal ArticleDOI
TL;DR: In this article, the effect of nano-LDHs and nano-TiO2 on the improvement in fire-resistant and anti-ageing properties of the APP-PER-MEL coating was investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Differential thermal analysis (DTA), Thermogravimetry (TG) and fire protection test.
Abstract: Flame-retardant nano-coatings have been prepared by adding nano-concentrates with nanometer layer double hydroxides (nano-LDHs) and nanometer titanium dioxide (nano-TiO2) to ammonium polyphosphate–pentaerythritol–melamine (APP–PER–MEL) coating. The dispersion and stability principle of nanoparticles is analyzed by using transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The effect of nano-LDHs and nano-TiO2 on the improvement in fire-resistant and anti-ageing properties of the APP–PER–MEL coating is investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Differential thermal analysis (DTA), Thermogravimetry (TG) and fire protection test. The DTA and TG data show that the thermal decomposition of nano-LDHs at 310–430 °C is helpful to the char formation of the APP–PER–MEL system at 300–440 °C. The XRD and SEM data show that the thermal decomposition of nano-LDHs leads to the formation of an intercalated nanostructure of the char and mixed metal oxides (Al2O3 and MgAl2O4). The intercalated nanostructure can improve the anti-oxidation property of the char structure. Accelerated ageing badly affects the chemical action and interaction of ammonium polyphosphate, pentaerythritol and melamine in traditional APP–PER–MEL coating, whereas the flame retardants in the nano-coating still have a very good interaction even after 500 h accelerated ageing. Nano-TiO2 can greatly improve anti-ageing properties of flame-retardant coating by its excellent ultraviolet-blocking power, and nanoscale interpenetrating network formed by uniformly dispersed nanoparticles can enhance the resistance of the coating to moisture in natural weathering.

Journal ArticleDOI
TL;DR: The plasmon-assisted enhancing optical properties were demonstrated by SERS of 2-naphthalenethiol (2NAT), an analyte with a well-defined SERS spectrum.
Abstract: although full characterization and determination of the yield of octahedra with respect to other shapes in the mixture are lacking. [2b] Under the reaction conditions described in this paper, at least 70% of the products are crystalline gold octahedra, permitting detailed analysis by electron microscopy and surface spectroscopy of these nanomaterials. The plasmon-assisted enhancing optical properties were demonstrated by SERS of 2-naphthalenethiol (2-NAT), an analyte with a well-defined SERS spectrum. The gold octahedral nanoparticles were synthesized in high yields by thermal treatment of HAuCl4-loaded polystyreneblock-poly(2-vinylpyridine) (PS-b-P2VP; 91500 gmol –1 105000 gmol –1 ) with a 1:2 ratio of Au III /pyridyl-groups, at a temperature of 250°C in air for 5 min. The block copolymer solution (0.5 wt% in toluene) was loaded with a predefined amount of HAuCl4(s), and spin-coated onto a native oxide capped silicon surface to form a monolayer of block copolymer micelles, followed by brief heating. Scanning electron

Journal ArticleDOI
TL;DR: In this paper, the crystal structures of these particles were investigated as a function of the size and the temperature using synchrotron radiation x-ray diffraction (XRD) measurement.
Abstract: High density, almost impurity-free and defect-free barium titanate (BaTiO3) fine particles with various sizes from 20to1000nm were prepared by the two-step thermal decomposition of barium titanyl oxalate and postheating treatment. The crystal structures of these particles were investigated as a function of the size and the temperature using synchrotron radiation x-ray diffraction (XRD) measurement. As a result, the size-induced ferroelectric (tetragonal-cubic) phase transition observed at around 30nm. Moreover, the temperature dependence of the crystal structures revealed that one phase transition at 135°C separated into two kinds of phase transition behaviors with decreased particle sizes, i.e., the tetragonal-cubic phase transition temperature was constant at 135°C despite particle sizes while the cell volume expansion temperature shifted to low temperature with decreasing particle sizes. Moreover, the temperature dependence of Raman scattering spectra clarified that the temperature at a discontinuous c...

Journal ArticleDOI
TL;DR: In this article, a first-order kinetic model for the thermal decomposition of boric acid was proposed and the Suzuki and Coats-Redfern methods were applied for the kinetic investigation.
Abstract: The kinetic parameters of the thermal decomposition of boric acid have been investigated by using TGA data. Suzuki and Coats-Redfern methods have been applied for the kinetic investigation. It was determined that decomposition kinetics of boric acid occurred in two steps and both regions suitably fit a first-order kinetic model. According to Coats-Redfern method, the activation energy and frequency factor were found as 79.85 kJ·mol-1 and 3.82x 104 min-1 for region I and 4.79 kJ·mol-1 and 4.045 x 10-5 min-1 for region II, respectively. The activation energies and frequency factors were found as 4.45 kJ·mol-1 and 4.08 x108 min-1 for the Suzuki method.

Journal ArticleDOI
Changjie Cong1, Jianhe Hong1, Qingzhen Liu1, Lei Liao1, Keli Zhang1 
TL;DR: In this article, Ni-doped ZnO particles were synthesized by rheological phase reaction-precursor method and the thermal decomposition of oxalate precursors was studied by thermogravimetry and differential thermal analysis in air atmosphere.

Journal ArticleDOI
TL;DR: In this article, the solid-solid interaction and thermal decomposition behavior of 2wt% Ag2O in ZnO powder have been investigated by using thermogravimetry analysis and differential thermal analysis.
Abstract: The solid-solid interaction and thermal decomposition behavior of 2wt% Ag2O in ZnO powder have been investigated by using thermogravimetry analysis and differential thermal analysis. Ag2O, which remained stable in ZnO up to 200°C, was observed to be thermally decomposed to Ag+ ions in the temperature range of 200–250°C, suggesting that Ag+ ions were diffused into ZnO matrix. Based on thermal analysis, ZnO:Ag films have been fabricated on a (001) Al2O3 substrate using specifically synthesized Ag-doped ZnO target by pulsed laser deposition. The effect of (002) peak shift on the structural property of Ag-doped ZnO films has been systematically characterized to investigate the influence of the substitution of Ag+ for Zn+. Ag-doped p-type ZnO films have been successfully grown at a deposition temperature in the range of 200–250°C, which is in good agreement with thermally decomposed temperature for Ag2O to Ag+ in ZnO powder, with hole concentrations of 4.9×1016–6.0×1017cm−3, hole mobilities of 0.29–2.32cm2∕Vs,...

Journal ArticleDOI
TL;DR: A large quartz reactor was constructed to study the decomposition of methane in a fluidized bed of carbon-black particles, which acts as a catalyst as mentioned in this paper, and experiments were run for 400-2000 min using three types of carbon black, temperatures of 810-980 °C, and space velocities of 95-210 ǫ h - 1.

Journal ArticleDOI
TL;DR: In this paper, thermal reactions between 1.0 M LiPF 6 in 1:1:1 ethylene carbonate and metal-oxide cathode particles were investigated by analyzing both the liquid electrolyte and solid cathode particle through the combined use of nuclear magnetic resonance spectroscopy, gas chromatography with mass selective detection, scanning electron microscopy with energy dispersive X-ray spectroscopic, X-Ray photoelectron spectroscope, and thermogravimetric analysis.
Abstract: Thermal reactions between 1.0 M LiPF 6 in 1:1:1 ethylene carbonate/dimethyl carbonate/diethyl carbonate and metal-oxide cathode particles were investigated by analyzing both the liquid electrolyte and solid cathode particles through the combined use of nuclear magnetic resonance spectroscopy, gas chromatography with mass selective detection, scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The reactions between the electrolyte and cathode particles inhibit the thermal decomposition of the electrolyte and modify the surface of the cathode particles. The Li 2 CO 3 on the surface of the metal oxides is removed and replaced by a complex mixture including poly(ethylene oxide), polycarbonate, ROCO 2 Li, LiF, and Li x PO y F z . Higher surface concentration of Li 2 CO 3 on LiNi 0.8 Co 0.2 O 2 allows a fragile temperature-dependent equilibrium to be established, accounting for the thermal stability of the electrolyte. Higher temperature leads to more Li x PO y F z and less Li 2 CO 3 on the surface. With LiCoO 2 , no equilibrium is established due to lower surface concentration of Li 2 CO 3 . Consequently, thermal reactions of the electrolyte with LiCoO 2 generate decomposition products, including Li x PO y F z and cobalt fluorides on the surface and bulk electrolyte decomposition. Independent addition of Li 2 CO 3 enhances the thermal stability of the LiPF 6 -based electrolyte, confirming the thermal-stabilizing properties of Li 2 CO 3 surface films. The addition of a carbonate solution of PF 5 to LiNi 0.8 Co 0.2 O 2 generates LiPF 6 in the solution and Li x PO y F z on the surface.

Journal ArticleDOI
TL;DR: Monodisperse lanthanide oxysulfide nanoplates and short nanorods were synthesized by the thermal decomposition of molecular precursors in the presence of oxygen and show unusual fluorescence properties obviously differing from the bulk powder phosphors.
Abstract: Monodisperse lanthanide oxysulfide nanoplates and short nanorods were synthesized by the thermal decomposition of molecular precursors in the presence of oxygen. The nanoplates have uniform thicknesses and further self-organize to nanowires up to micron scale. The Eu2O2S and Eu3+-doped Gd2O2S nanocrystals both show unusual fluorescence properties obviously differing from the bulk powder phosphors, which are related to the surface-modification effects.