共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Uraiwan Sirimahachai Nicholas Ndiege Ramesh Chandrasekharan Sumpun Wongnawa Mark A. Shannon 《Journal of Sol-Gel Science and Technology》2010,56(1):53-60
Nanosized TiO2 and nano-anatase TiO2 decorated on SiO2 spherical core shells were synthesized by using a sol–gel method. The synthesized pure TiO2 nano particle and TiO2 grafted on SiO2 sphere with various ratios have been characterized for their structure and morphologies by X-ray diffraction (XRD), X-ray
photoelectron spectroscopy (XPS), Fourier transform infrared spectrophotometry (FTIR) and transmission electron microscopy
(TEM). Their surface areas were measured using the BET method. The photocatalytic activity of all nanocomposites was investigated
using methylene blue as a model pollutant. The synthesized TiO2/SiO2 particles appeared to be more efficient in the degradation of methylene blue pollutant, as compared to pure TiO2 particles. 相似文献
3.
Water responsive SiO2/cellulose nanocomposite hydrogels and films were constructed, for the first time, by dispersing SiO2 nanoparticles into cellulose solution in LiOH/urea solvent, and then by crosslinking with epichlorohydrin or regeneration in coagulation bath, respectively. The cellulose nanocomposite materials were characterized by Field emission scanning electron microscopy, FTIR, dynamic rheology, wide angle X-ray diffraction and mechanical test. The SiO2/cellulose nanocomposites at wet state or in water displayed unique behaviors, showing higher light transmittance than those before contacting with water. The results revealed that strong hydrogen-bonding interaction among water, cellulose and SiO2 led the good dispersion of SiO2 nanoparticles in the cellulose matrix. The incorporation of SiO2 nanoparticles improved the transmittance and mechanical strength of the cellulose hydrogels, and also enhanced the mechanical strength of the films. Especially, the cellulose/SiO2 nanocomposite films were milky at dry state, and changed to transparent after being soaked in water, different from the cellulose film without the SiO2 nanoparticles. In our findings, SiO2 and cellulose with water could form strong hydrogen bonding to create a homogenous network structure. The cellulose/SiO2 composite as a smart material exhibited moisture and solvent responsiveness, showing potential applications in moisture detection. 相似文献
4.
Li Chen Haixia Shen Zhen Lu Cang Feng Su Chen Yanru Wang 《Colloid and polymer science》2007,285(13):1515-1520
TiO2–SiO2 composite nanoparticles were prepared by a sol–gel process. To obtain the assembly of TiO2–SiO2 composite nanoparticles, different molar ratios of Ti/Si were investigated. Polyurethane (PU)/(TiO2–SiO2) hybrid films were synthesized using the “grafting from” technique by incorporation of modified TiO2–SiO2 composite nanoparticles building blocks into PU matrix. Firstly, 3-aminopropyltriethysilane was employed to encapsulate TiO2–SiO2 composite nanoparticles’ surface. Secondly, the PU shell was tethered to the TiO2–SiO2 core surface via surface functionalized reaction. The particle size of TiO2–SiO2 composite sol was performed on dynamic light scattering, and the microstructure was characterized by X-ray diffraction and
Fourier transform infrared. Thermogravimetric analysis and transmission electron microscopy (TEM) employed to study the hybrid
films. The average particle size of the TiO2–SiO2 composite particles is about 38 nm when the molar ratio of Ti/Si reaches to1:1. The TEM image indicates that TiO2–SiO2 composite nanoparticles are well dispersed in the PU matrix. 相似文献
5.
6.
A. S. Vorokh N. S. Kozhevnikova A. A. Uritskaya A. Magerl 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(7):1132-1137
The region of stable coexistence of Cd(OH)2 and CdS as a function of pH and the concentration of the complex-forming agent (ammonia) was determined by thermodynamic analysis with the purpose of the preparation of Cd(OH)2 cadmium hydroxide particles surrounded by cadmium sulfide CdS shells. In this region, powders were obtained by chemical precipitation during various precipitation times from aqueous solutions. X-ray diffraction was used to track the growth of the CdS nanophase of a disordered structure and hexagonal Cd(OH)2 phase consumption with time. It was found by complexonometry that part of cadmium formed insoluble structures as a result of the formation of continuous nanosized CdS shells on single crystalline Cd(OH)2 particles. A comparative analysis of the experimental data was used to determine the kinetics of formation of nucleus-shell Cd(OH)2/CdS particles in the system. 相似文献
7.
Shu-Yu Wang Le-Yan Zou Yuan-Chen Liang Guang-Ming Li 《Research on Chemical Intermediates》2018,44(2):1025-1033
Silver nanoparticles have good sterilization performance due to their small size and large specific surface area, while the small size also brings about reunification and reduces the sterilization activity. To resolve the problem, magnesium hydroxide [Mg(OH)2] microsphere was designed as a supported material to load silver particles on its surface. Mg(OH)2 microspheres were successfully synthesized under the control of a biotemplate of eggshell membrane. X-ray diffraction, thermal gravimetric analysis/differential scanning calorimetry, and transmission electron microscopy were performed to characterize the Mg(OH)2 microspheres. The results indicate that the Mg(OH)2 microspheres of average size ~ 2 μm were formed from nanoflakes. The silver nanoparticles were loaded on the surface of Mg(OH)2 microspheres to form Mg(OH)2/Ag nanocomposite, which exhibited enhanced antibacterial effect compared to that of silver nanoparticles. The enhanced antibacterial mechanism was investigated in detail. 相似文献
8.
This work includes the applications of radiation processing to decompose dimethyl phthalate (DMP) with gamma and gamma/H2O2 processes. Changes in amounts of DMP, dissolved oxygen, total acidity and formaldehyde with irradiation dose were followed. The qualitative analysis of the DMP and the intermediates were determined by using a gas chromatography combined to mass spectrometry and ion chromatography. The results indicated that degradation rate of DMP was affected by H2O2 concentration, irradiation dose and removal efficiency of 25 mg L?1 DMP can reach 100% for 1.42 kGy irradiation dose in the concentration of 4.8 mM H2O2, respectively. 相似文献
9.
Jinhe Sun Yongzhong Jia Yan Jing Ying Yao Wu Li 《Russian Journal of Inorganic Chemistry》2008,53(1):36-39
Cu(OH)2 nanowires with a diameter of 8–10 nm and lengths of tens of micrometers were fabricated in the basic solution by dropping
simply NaOH solution into CuCl2 solution at ambient temperature. The formation mechanism of nanowires was discussed. Scanning electron microscopy (SEM),
transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the samples.
This article was submitted by the authors in English. 相似文献
10.
V. S. Savenko 《Russian Journal of Inorganic Chemistry》2007,52(3):465-467
Be2(OH)2CO3 solubilities at 25°C in 0.7 M NaClO4 solutions containing variable NaHCO3 and Na2CO3 concentrations has been experimentally determined. The solubilities increase with increasing carbonate alkalinity. The results of the experiments do not contradict the suggestion that the mixed hydroxocarbonate complex Be2(OH)2CO 3 2? is the major beryllium solute species. At fluoride concentrations higher than 250 μmol/L, the Be2(OH)2CO3 solubilities noticeably increase as a result of the formation of beryllium fluoride complexes. 相似文献
11.
12.
Jiahong Zheng Runmei Zhang Xingang Wang Pengfei Yu 《Research on Chemical Intermediates》2018,44(11):6637-6648
Two kinds of electrode materials Ni(OH)2 and Ni(OH)2@Zn(OH)2 composite are fabricated on nickel foam. Electrochemical experiments indicate Ni(OH)2@Zn(OH)2 composite deserves further study due to high specific capacitance and good cycle stability, so that it can achieve energy storage and conversion as much as possible. When the hydrothermal time is different, the electrochemical performance of the sample is also different. Accurately, samples can obtain better electrochemical performance at 15 h, and the maximum specific capacitance of Ni(OH)2@Zn(OH)2 is 7.87 F cm?2 compared to Ni(OH)2 (0.61 F cm?2) at 5 mA cm?2. Even at 50 mA cm?2, specific capacitance is 5.24 F cm?2 and rate capability is 66.6%. Furthermore, Ni(OH)2@Zn(OH)2-15 h loses 19.8% after 1000 cycles, revealing the composite has an outstanding stable cycle. These properties also indicate Ni(OH)2@Zn(OH)2-15 h is a promising electrode material. 相似文献
13.
A. V. Petrov I. V. Murin A. K. Ivanov-Schitz 《Russian Journal of General Chemistry》2017,87(7):1456-1460
Electronic structure of (SiO2)3 clusters was calculated by the density functional method. Charge states were determined using various functionals, bond lengths and total energies of clusters were estimated. 相似文献
14.
Reverse micellar microemulsions were utilised to synthesise stable lead titanate colloids from typical sol–gel type molecular
precursors. The particles of a few nanometres in diameter that formed by hydrolysis in the micelle cores demonstrated a nanocrystalline
texture without the need for thermal treatment. In a chemical solution deposition routine based on the nanoparticle dispersions,
ferroelectric PbTiO3 thin films showing excellent remanent polarisation of more than 50 μC cm−2 were derived. The electrical characteristics of the layers were correlated to their microstructure which was controlled by
the precursor composition and the annealing conditions. A columnar morphology that was realised by spinning on coatings of
up to 100 nm in individual thickness proved most favourable with respect to the ferroelectric performance of the films. 相似文献
15.
Chun-guang Gao Yong-xiang Zhao Yin Zhang Dian-sheng Liu 《Journal of Sol-Gel Science and Technology》2007,44(2):145-151
The Ni/ZrO2/SiO2 aerogels catalysts were synthesized via three different routes: (i) impregnation ZrO2–SiO2 composite aerogels with a aqueous solution of Ni(NO3)2, (ii) impregnation SiO2 aerogels with a mixed aqueous solution of Ni(NO3)2 and ZrO(NO3)2 · 2H2O, (iii) one-pot sol–gel procedure from precursors Ni(NO3)2/ZrO(NO3)2 · 2H2O/Si(OC2H5)4. These catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), ammonia temperature-programmed
desorption (NH3-TPD), N2 adsorption–desorption isotherms and Fourier transform infrared (FT-IR). The Liquid-phase hydrogenation of maleic anhydride
(MA) was performed over these catalysts. The results revealed that the different preparation routes result in a difference
between the obtained samples, concerning the crystal structure and composition, surface acidity, mixed level of each component,
texture, and catalytic selectivity. 相似文献
16.
V. V. Voitylov A. V. Voitylov E. N. Korytkova V. P. Romanov S. V. Ul’yanov V. V. Gusarov 《Russian Journal of Applied Chemistry》2008,81(2):207-211
Behavior of hydrosilicate nanotubes of composition Mg3Si2O5(OH)4 in aqueous dispersions was studied. Experiments devoted to observation of steady-state and relaxation electro-optical effects demonstrated that, irrespective of their initial concentration in water, nanotubes form stable bulk aggregates with weak anisotropy, rather than a homogeneous system of separate suspended nanosize cylinders. 相似文献
17.
S. A. Kirillova V. I. Almjashev V. V. Gusarov 《Russian Journal of Inorganic Chemistry》2011,56(9):1464-1471
Phase equilibria in a miscibility gap of the SiO2-TiO2 system were studied. A visual polythermal analysis and annealing of samples were performed in a Galakhov microfurnace. The
microstructure and composition of the obtained samples were investigated by scanning electron microscopy and electron probe
microanalysis. A critical analysis of the experimental data was made. Thermodynamically optimized based on the sub-regular
solution model, a phase diagram of the SiO2-TiO2 system was constructed. 相似文献
18.
The stability and solubility of UO2(OH)2 has been studied as a function of the humic acid concentration in 0.1M NaClO4, in the pH range from 4 to 7 under normal atmospheric conditions. The solid phase under investigation has been prepared by
alkaline precipitation and characterized by TGA, ATR-FTIR, XRD, SEM and solubility measurements. According to the experimental
data UO2(OH)2 is stable and remains the solubility limiting solid phase even in the presence of increased humic acid concentration in the
solution. However, humic acid affects texture and particle size of the solid phase. Increasing humic acid concentration results
in decreasing crystallite size of the UO2(OH)2 solid phase. Based on the solubility data, the logK
sp
(UO2(OH)2) has been evaluated to be −22.0±0.3 and the stability constant for the UO2(OH)HA(I) species has been estimated to be logβ
1101 = 15.3±0.5. 相似文献
19.
The structures and stability of pentacoordinate germylenoid PhCH2(OH)CH3GeLiF were first theoretically studied by density functional theory. Two equilibrium structures, the three-membered ring (1a) and the p-complex (1b) structures, were located. Their energy are in the order of 1b > 1a. The Ge-O coordination energies at the B3LYP/6-311+G(d, p) level are 13.6 and 0.2 kJ/mol in 1a and 1b, respectively. The insertion reactions with CH3F indicate that germylenoid PhCH2(OH)CH3GeLiF is more stable than germylene PhCH2(OH)CH3Ge. The insertion barrier of 1a with CH3F is only 3.1 kJ/mol higher than that of PhCH3CH3GeLiF, indicating that the oxygen coordination PhCH2(OH)CH3GeLiF has the same stability as PhCH3CH3GeLiF. 相似文献
20.
Porous CuO/SiO2 hollow microspheres were synthesized via an impregnation method using pure SiO2 hollow microspheres as the supporter, and Cu species as the functional material. The hollow microspheres were characterized by X-ray diffraction, BET surface area, temperature-programmed reduction, transmission electron microscopy, and scanning electron microscopy. The catalytic activities of the CuO/SiO2 hollow microspheres were investigated via the removal of the total chemical oxygen demand (COD) in the oxidation of phenol solution with air as an oxidant. The influence of various reaction parameters such as the reaction temperature, the partial pressure of O2, and the initial pH of the solution were studied in detail. The coordination, dispersion and aggregation degree of copper species on porous materials play an important role for the COD removal of the phenol aqueous solution. 相似文献