共查询到20条相似文献,搜索用时 12 毫秒
1.
Qing-Yun Xiang Jiang-Li Cao Yue Li Ya-Li Huang Yu Shi Jie Wang Li-Bin Mo Wen-Qing Yao 《Catalysis Surveys from Asia》2016,20(3):133-140
The environmental-friendly hematite iron oxide (α-Fe2O3) has important application prospects in the photocatalysis field owing to its narrow indirect band gap. Here, we report a band gap engineering of α-Fe2O3 by incorporation of electrochemically-generated atomic hydrogen at moderate conditions. The ultraviolet–visible spectra show the reduction of the α-Fe2O3 band gap after hydrogenation and the absorption region from 200–800 nm is enhanced, especially in the visible light region. First principles calculation reveals the mixing of the new hybrid energy level with the valence band top resulting in a decrease in the band gap of α-Fe2O3. Further photocatalytic degradation experiments of dyes demonstrate that the photocatalytic efficiency of α-Fe2O3 can be greatly enhanced by the atomic hydrogen incorporation. The hydrogenated α-Fe2O3 can be easily recycled by magnets and has good photocatalytic stability. These findings offer possibilities for utilizing this inexpensive and earth-abundant oxide materials in the pollution controlling areas. 相似文献
2.
Shreelekha N. Khatavkar Shrikrishna D. Sartale 《Journal of Solid State Electrochemistry》2017,21(9):2555-2566
In the present study, iron oxide (α-Fe2O3) thin films with good adhesion on stainless steel substrates are deposited by liquid phase deposition (LPD) technique, which is additive and binder-free. Iron oxyhydroxide (FeOOH) thin films are formed by means of a ligand-exchange equilibrium reaction of metal-fluoro complex ions and an F?ions consuming reaction by using boric acid (H3BO3) as a scavenging agent. These films are annealed at 500 °C to get α-Fe2O3 thin films. The transformation from hydrophobic to hydrophilic nature of the films is observed due to annealing. The films are characterized by different techniques. The α-Fe2O3 film is checked for electrochemical supercapacitive performance in Na2SO3 solutions of various concentrations. Specific capacitance is calculated from cyclic voltammetry at numerous scan rates (5–200) mV s?1. The highest obtained value of specific capacitance is 582 F g?1 at 5 mV s?1 for 0.5 M Na2SO3 electrolyte. The maximum values of specific power and specific energy are 6.9 and 53.4 Wh kg?1 from the charge-discharge curve at the current density 2 mA cm?2 in 0.5 M Na2SO3 electrolyte. 相似文献
3.
V. N. Krasil’nikov O. I. Gyrdasova A. P. Tyutyunnik T. V. Diachkova I. V. Baklanova V. V. Marchenkov A. N. Domozhirova V. G. Bamburov 《Doklady Chemistry》2018,481(2):161-165
Low-dimension ferromagnetic maghemite γ-Fe2O3 was synthesized through a precursor route, using basic iron formate Fe(OH)(HCOO)2 as a precursor. Conditions of formation of γ-Fe2O3 and the temperature range of its existence on heating in air were determined. The saturation magnetization of γ-Fe2O3 produced through heating the precursor at 350°C 57.5 (T = 4.2 K) and 43.8 emu/g (T = 300 K). 相似文献
4.
M. I. Ivanovskaya D. A. Kotikov V. V. Pan’kov Yu. Lubina 《Russian Journal of General Chemistry》2010,80(10):1908-1912
The structural features and magnetic properties of composite materials Fe2O3-SiO2 consisting of γ-Fe2O3 nanoparticles in an amorphous porous matrix of SiO2 were considered. The studied samples were synthesized by the sol-gel method. The structure of γ-Fe2O3-SiO2 depending on the heating temperature was studied by electron microscopy, X-ray diffraction analysis, ESR and IR spectroscopy.
Magnetic measurements were performed on a SQUID magnetometer in the range 2–350 K. 相似文献
5.
T. N. Afonasenko N. N. Leont’eva V. P. Talzi N. S. Smirnova G. G. Savel’eva A. V. Shilova P. G. Tsyrul’nikov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(10):1939-1945
The textural and structural properties of mixed oxides Ga2O3–Al2O3, obtained via impregnating γ-Al2O3 with a solution of Ga(NO3)3 and subsequent heat treatment, are studied. According to the results from X-ray powder diffraction, gallium ions are incorporated into the structure of aluminum oxide to form a solid solution of spinel-type γ-Ga2O3–Al2O3 up to a Ga2O3 content of 50 wt % of the total weight of the sample, accompanied by a reduction in the specific surface area, volume, and average pore diameter. It is concluded that when the Ga2O3 content exceeds 50 wt %, the β-Ga2O3 phase is observed along with γ-Ga2O3–Al2O3 solid solution. 71Ga and 27Al NMR spectroscopy shows that gallium replaces aluminum atoms from the tetrahedral position to the octahedral coordination in the structure of γ-Ga2O3–Al2O3. 相似文献
6.
Sodium aluminophosphate samples with composition 43.8Na2O12.5Al2O343.8P2O5 were prepared by the sol–gel route using different precursors and working in different pH ranges from pH < 1 up to pH > 10. The structures of the gels and of the corresponding glasses were investigated by solid state NMR and compared to that of a glass with the same composition prepared by a traditional melting process. In addition to bulk materials, thin films were deposited by dip coating on silica glasses. Applying secondary neutral mass spectrometry (SNMS), the expected elements and residual carbon were identified. The surfaces of the coatings and fracture surfaces of bulk material were investigated using atomic force microscopy (AFM). Solid state NMR revealed that samples prepared via a lactate route exhibited local Al and P environments closest to that of the melt-prepared glass, with the highest extent of Al-O-P connectivity. 相似文献
7.
Jian-Jin Huang Yu-Jen Hsiao Te-Hua Fang Tao-Hsing Chen 《Journal of Sol-Gel Science and Technology》2012,62(1):75-78
Hexagonal Ba5Ta4O15 were synthesized by a sol–gel process at temperatures of 700–900 °C. The microstructure properties and morphology are studied
by X-ray diffraction and scanning electron microscope. Traces of the Ba5Ta4O15 component were detected by energy dispersive X-ray analysis. A higher temperature enhanced higher atom mobility and caused
the growth direction to change and created hexagonal square makes obvious good quality of samples. The visible light absorption
edges of the Ba5Ta4O15 nanorods and were corresponded to band-gap energies of 4.0 eV. 相似文献
8.
V. M. Kuimov A. Sh. Khaliullina A. A. Pankratov B. D. Antonov L. A. Dunyushkina 《Russian Journal of Electrochemistry》2018,54(2):170-177
Conditions of the chemical solution deposition of CaZrO3-based electrolyte films on supporting composite electrodes are studied. The films are formed on the composites of CaZrO3 with metal oxides СuO, Fe2O3, and NiO. The morphology and the phase and elemental composition of supports and films are studied as well as the gas permeability and conductivity of films. It is concluded that composites of calcium zirconate with nickel can be recommended as the supporting anodes for the proton-conducting CaZr0.9Y0.1O3–δ film electrolyte. 相似文献
9.
E. A. Baryshnikova V. V. Batrakov V. V. Egorov 《Russian Journal of Electrochemistry》2009,45(7):765-771
The adsorption of chloride ions on γ-Fe2O3 oxide (maggemite) from nitrate solution is studied using the method of potentiometric titration and an ion-selective electrode. The specific character of adsorption is determined. It is shown that the maggemite surface coverage with Cl? ions increases with increasing concentration of ions in the solution, decreasing pH value, and increasing potential. The adsorbability of ions changes drastically in the pH range about pH0 (γ-Fe2O3)6.2. It is found that the adsorption of chloride ions from neutral nitrate solution exponentially increases in the potential range from 0.1 to 1.0 V. The type of adsorption isotherm and the adsorption parameters are determined. It is found that, in the absence of external polarization, the concentration dependences of adsorption of Cl? ions are complex-shaped, and their initial portions are described by the Langmuir isotherm. Further increase of adsorption is explained by the penetration of Cl? ions inwards the oxide. 相似文献
10.
L. A. Dunyushkina V. M. Kuimov A. A. Pankratov O. G. Reznitskikh A. Sh. Khaliullina 《Russian Journal of Electrochemistry》2016,52(11):1057-1063
Compact CaZr0.9Y0.1O3–δ (CZY) film on a porous SrTi0.8Fe0.2O3–δ (STF) support is obtained using the technique of deposition from solutions of inorganic salts in ethanol. According to the data of scanning electron microscopy (SEM), the film has a nanoporous granular structure with the grain size of 0.2 to 1 μm. The thickness of the CZY film on the STF support is about 3 μm after 15-fold solution application. The results of studying the elemental composition showed that elements of the support diffuse into the film in the course of synthesis. Analysis of the data of impedance spectroscopy shows that conductivity of the CZY film is limited the grain bulk. It is assumed that the comparatively low conductivity activation energy of the film (50.3 kJ/mol) is due to diffusion of elements of the STF support that results in variation of the film composition and properties. 相似文献
11.
Masoud Salavati-Niasari Fatemeh Davar Masoud Farhadi 《Journal of Sol-Gel Science and Technology》2009,51(1):48-52
Nanocrystalline Copper aluminate (CuAl2O4) was prepared by sol–gel technique using aluminum nitrate, copper nitrate, diethylene glycol monoethyl ether and citric acid
were used as precursor materials. This method starts from of the precursor complex, and involves formation of homogeneous
solid intermediates, reducing atomic diffusion processes during thermal treatment. The formation of pure crystallized CuAl2O4 nanocrystals occurred when the precursor was heat-treated at 600 °C in air for 2 h. The stages of the formation of CuAl2O4, as well as the characterization of the resulting compounds were done using thermo–gravimetric analysis, X-ray diffraction,
scanning electron microscopy and Fourier transform infrared spectroscopy. The products were analyzed by transmission electron
microscopy and ultraviolet–visible (UV–Vis) spectroscopy to be round, about 17–26 nm in size and E
g = 2.10 eV. 相似文献
12.
Alexander Efremov Junmyung Lee Jihun Kim 《Plasma Chemistry and Plasma Processing》2017,37(5):1445-1462
The effects of both CF4/O2 and Ar/O2 mixing ratios in three-component CF4 + O2 + Ar mixture on plasma parameters, densities and fluxes of active species determining the dry etching kinetics were analyzed. The investigation combined plasma diagnostics by Langmuir probes and zero-dimensional plasma modeling. It was found that the substitution of CF4 for O2 at constant fraction of Ar in a feed gas produces the non-monotonic change in F atom density, as it was repeatedly reported for the binary CF4/O2 gas mixtures. At the same time, the substitution of Ar for O2 at constant fraction of CF4 results in the monotonic increase in F atom density toward more oxygenated plasmas. The natures of these phenomena as well as theirs possible impacts on the etching/polymerization kinetics were discussed in details. 相似文献
13.
L. T. Denisova L. A. Irtyugo Yu. F. Kargin V. M. Denisov V. V. Beletskii 《Russian Journal of Inorganic Chemistry》2017,62(6):814-817
Stannates Dy2Sn2O7 and Ho2Sn2O7 are produced by solid-phase synthesis from Dy2O3 (Ho2O3)–SnO2 stoichiometric mixtures by calcining at 1473 K. The molar heat capacity of holmium and dysprosium stannates is measured by differential scanning calorimetry (DSC) in the temperature range 370–1000 K. The experimental data are used to calculate thermodynamic properties (enthalpy change H°(T)–H°(370 K), entropy change S°(T)–S°(370 K), and the reduced Gibbs free energy Φ°(T)) of the synthesized compound. 相似文献
14.
Nanorods of orthorhombic V3O7 · H2O with the parameters a = 16.805 Å, b = 9.428 Å, and c = 3.660 Å are prepared under hydrothermal conditions (T = 180–190°C, τ = 30–40 h) from the V2O5 · nH2O/H2C2O4 · 2H2O composite. The particle diameter is 40–70 nm, and the length is several micrometers. The IR spectra, electric conductivity, and thermal properties of the nanorod powder are studied. In air V3O7 · H2O begins to decompose at temperatures above 150°C, and at 350°C nanobelts V2O5 40–100 nm wide and 40 µm long are formed. A mechanism of nanostructure formation is suggested. 相似文献
15.
The paper presents experimental results pertaining to the reduction of oxide mixtures namely (Fe2O3 + CuO) and (Fe2O3 + Co3O4), by low-temperature hydrogen plasma in a microwave hydrogen plasma set-up, at microwave power 750 W and hydrogen flow rate 2.5 × 10?6 m3 s?1. The objective was to examine the effect of addition of CuO or Co3O4, on the reduction of Fe2O3. In the case of the Fe2O3 and CuO mixture, oxides were reduced to form Fe and Cu metals. Enhancement of reduction of iron oxide was marginal. However, in the case of the Fe2O3 and Co3O4 mixture, FeCo alloy was formed within compositions of Fe70Co30, to Fe30Co70. Since the temperature was below 841 K, no FeO formed during reduction and the sequence of Fe2O3 reduction was found to be Fe2O3 → Fe3O4 → Fe. Reduction of Co3O4 preceded that of Fe2O3. In the beginning, the reduction of oxides led to the formation of Fe–Co alloy that was rich in Co. Later Fe continued to enter into the alloy phase through diffusion and homogenization. The lattice strain of the alloy as a function of its composition was measured. In the oxide mixture in which excessive amount of Co3O4 was present, all the Co formed after reduction could not form the alloy and part of it appeared as FCC Co metal. The crystallite size of the alloy was in the range of 22–30 nm. The crystal size of the Fe–Co alloy reduced with an increase in Co concentration. 相似文献
16.
J. Ma C. Z. Chen D. G. Wang X. G. Meng J. Z. Shi 《Journal of Sol-Gel Science and Technology》2010,54(1):69-76
Two glasses of the CaO-MgO-P2O5-SiO2 system with different MgO contents (0 and 10 mol%, respectively) have been synthesized by sol–gel method. The degradation
of glass samples was evaluated through the weight loss in the tris-(hydroxymethyl)-aminomethane and hydrochloric acid (Tris–HCl)
buffer solution, and the in vitro bioactivity was assessed by determining the changes in surface morphology and composition
after soaking in a simulated body fluid. Formation of the apatite-like layer on glasses surface was studied by means of X-ray
diffraction, Fourier-transform infrared, scanning electron microscopy. Results indicate that, with the partial substitution
of MgO for CaO in glass composition, the glass degradation decrease and the formation of apatite-like layer is delayed. Furthermore,
it is observed that the glass bioactivity is relative to its dissolution, and the effects of MgO on glass degradability and
bioactivity may be attributed to the influence of ionic field strength and distinct bonding configuration of glass. 相似文献
17.
-Fe2O3/polystyrene composite nanoparticles were synthesized in an oil/water microemulsion. Their structure was characterized by transmission electron microscopy, X-ray diffraction and Fourier transform-infrared spectrometry. An Ubbelonde viscometer, a Gouy balance and a model 283 potentiostat/galvanostat measured the molecular weight of the composite nanoparticles and their magnetic and electrical characteristics respectively. 相似文献
18.
B. Li Y. Y. Wang W. Q. Luo Y. H. Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(3):1619-1625
Radiation-induced degradation of the weakly and strongly 4-vinylpyridine basic ion exchange resins by gamma radiolysis was investigated in the presence of air and liquid water. This study is focused on evaluating the radiolytic gases (H2, CO, CO2 and CH4) and liquid products (water-solute TOC and NH4 +). The weakly basic resin yielded lower amounts of H2 and CO and higher amounts of CO2 than those of the strongly basic resin. Moreover, the strong basic resin tended to yield greater amounts of NH4 +. Resins were characterized by the FTIR spectroscopy technique and the results showed that the resins structures are relatively stable. 相似文献
19.
A quaternary super-ion-conducting system, 20CdI2 − 80[xAg2O − y(0.7V2O5 − 0.3B2O3)] where 1 ≤ x/y ≤ 3, has been prepared by melt quenching technique. The electrical conductivity measured was the order of 10−4 S/cm at room temperature. The values of silver-ion transport number obtained by electromotive force technique are nearly
unity. The thermoelectric power and electrochemical studies were done on the CdI2–Ag2O–V2O5–B2O3 system. The discharge and polarization characteristics were examined for different cathodes to evaluate the utility of these
cells as power sources for low energy applications. 相似文献
20.
The dependence of solid phase composition on the main parameters of the interaction in the CoSO4-K4P2O7-H2O system was studied. The synthesis conditions were determined and a crystalline cobalt(II) diphosphat of the composition
Co2P2O7 · 6H2O was synthesized. Its thermal properties were studied. The composition and the intervals, wherein the thermally stable products
of partial and complete dehydration of Co2P2O7 · 6H2O are formed, were specified. The final heat treatment product, anhydrous α-Co2P2O7, was identified and a sequence of the solid phase thermal transformations accompanying its formation was established. 相似文献