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1.
Xiaole Jiang Xingzheng Liu Qianqian Chen Risheng Jin Yu Lu Jingxiong Yu Ying Wu Yiming He 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(6):1683-1693
Ag2WO4/g-C3N4 composites with different Ag2WO4 concentration and calcination temperature were synthesized via a mixing and heating approach. Various techniques were used to investigate the characters of the as-prepared samples, such as thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy. The degradation of rhodamine B (20 ppm) under visible light was performed to investigate the photocatalytic activity of Ag2WO4/g-C3N4 composites. Results indicate that the Ag2WO4/g-C3N4 is actually Ag/Ag2WO4/g-C3N4 ternary system. 7.5 wt% Ag2WO4/g-C3N4 prepared at 300 °C presented the best photocatalytic performance in rhodamine B degradation. The degradation rate reaches 0.0679 min?1, which is 3.25 times higher than the value of pure g-C3N4. The enhanced activity is attributed to the synergetic effect of Ag2WO4, g-C3N4 and metal Ag. Additionally, cycling experiments also proved that the Ag2WO4/g-C3N4 photocatalyst has good stability. 相似文献
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Yanju Long Lingxin Li Shan Wang Yu Chen Lulu Wang Sifeng Zhang Lijun Luo Fengzhi Jiang 《Catalysis Letters》2018,148(12):3608-3617
A series of Bi2O3/Bi2O4 composites were prepared by calcining raw materials with different NaBiO3/KOH mass ratios. The Bi2O3/Bi2O4 photocatalysts were characterized by the various measurements and their photocatalytic performance was assessed by degradation of 17α-ethinyl estradiol (EE2). The Bi2O3/Bi2O4 photocatalysts have wider visible light absorption and lower fluorescence emission intensity than the commercial Bi2O3. So, they displayed superior performance in the degradation of EE2. After the adsorption equilibrium of EE2 was reached, the degradation efficiency of Bi2O3/Bi2O4 for EE2 can reach a maximum value of ~?100% in 12 min under the visible-light illumination. Degradation analysis results indicated that both holes (h+) and superoxide radical (·O2?) can affect the degradation efficiency of EE2. 相似文献
Graphical Abstract
4.
An oxygen-diluted partially premixed/oxygen-enriched supplemental combustion (ODPP/OESC) counterflow flame is studied in this paper. Flame images are obtained through experiments and numerical simulations with the GRI-Mech 3.0 chemistry. The oxygen dilution effects are revealed by comparing the flame structures and emissions with those of a premixed flame and partially premixed flame (PPF) at the same equivalence ratio (?Σ = 0.95 and ? f = 1.4). The results show that both PPF and ODPP/OESC flames have distinct double flame structures; however, the location of the premixed combustion zone and the distance between premixed/nonpremixed combustion zone are significantly different for these two cases. For the ODPP/OESC flame, the temperature in the premixed combustion zone is lower and the premixed zone itself is located farther downstream from the fuel nozzle, which leads to reduction of NO and CO emissions, as compared to those of the PPF. Therefore, by adjusting the distribution of the oxygen concentration in the premixed and nonpremixed combustion zones, the ODPP/OESC can effectively balance the chemical reaction rate in the entire combustion zone and, consequently, reduce emissions. 相似文献
5.
The phase relationships in the Na2ZnP2O7–LiKZnP2O7 system are studied. They are represented by a mixture of the starting components in the subsolidus region. The eutectic was found at a temperature of 640°C and composition of 0.5LiKZnP2O7. The phase formation of this system is compared with the previously studied NaKZnP2O7–LiKZnP2O7 system. It is shown that a structural factor affects the geometry of the state diagrams. 相似文献
6.
L. P. Mezentseva A. V. Osipov V. L. Ugolkov V. F. Popova T. P. Maslennikova S. K. Kuchaeva A. V. Yakovlev 《Glass Physics and Chemistry》2018,44(5):423-427
Nanosized La1–xDyxPO4 · nH2O powders are synthesized by the sol-gel method using direct and reverse precipitation. The formation of a continuous series of hexagonal solid solutions based on LaPO4 · nH2O is confirmed by the XRD and DSC/TG methods. A continuous series of monoclinic solid solutions based on LaPO4 is formed at temperatures higher than 600°C. A reflex corresponding to a tetragonal form of DyPO4 is formed during the calcination of DyPO4 powder at 850°C. Two types of solid solutions are observed at temperatures of 1000–1200°C, namely, monoclinic solutions based on LaPO4 (to x ≈ 0.7) and tetragonal solutions based on DyPO4 (0.90 ≤ x ≤ 1.0). The results are compared depending on the methods of nanopowder synthesis. 相似文献
7.
Effects of ZnO–B2O3 (ZB) addition on the densification, phase evolution and microwaves dielectric properties of Ba4Sm9.33Ti18O54 (BST) ceramics for low-temperature fired applications have been investigated. The sintering temperature of BST ceramics can be effectively lowered to about 1000°C with introduction of ZB. Tungsten bronze like single phase is observed in the BST ceramics with 0.5 and 1.0% ZB. However, Sm2Ti2O7 secondary phase appears when ZB addition reaches 2%, and Sm2Ti2O7 phase gradually increases with the increase ZB addition. Microwave dielectric properties of the present ceramics are strongly dependent on phase constitution and density. Optimal microwave dielectric properties of ε = 63.4, Qf = 2830 GHz, τ f =–8.8 ppm/°C is obtained for BST ceramics with 1% ZB addition. 相似文献
8.
L. A. Angolenko G. D. Semchenko E. E. Starolat S. A. Savina M. A. Kushchenko S. V. Tishchenko V. V. Povshuk 《Refractories and Industrial Ceramics》2009,50(5):387-390
A study has been made on the effects of the amount of silicon nitride and graphite on the physicomechanical properties of
Al2O3–Si3N4–C composites for lining purposes. Adding 2.5–5.0 wt.% silicon nitride and 0.5 wt.% reactive alumina improves the properties,
raises their apparent density, and increases the mechanical strength, while reducing the open porosity. Optimized compositions
have been determined for refractory materials of Al2O3–Si3N4–C composition, and it has been found that to attain the higher values of physicomechanical properties the amount of graphite
should constitute 5–10 wt.%. 相似文献
9.
Marta Legawiec-Jarzyna Wojciech Juszczyk Magdalena Bonarowska Zbigniew Kaszkur Leszek Kępiński Zbigniew Kowalczyk Zbigniew Karpiński 《Topics in Catalysis》2009,52(8):1037-1043
A series of Pt/Al2O3 catalysts were prepared by the impregnation method and were characterized by TEM, XRD, H2 and CO chemisorptions, and investigated in the hydrodechlorination of tetrachloromethane. Three Pt-rich, Pt–Au/Al2O3 catalysts (Pt100, Pt95Au5 and Pt90Au10) showed a similar metal particle size (~2.5–2.7 nm), so observed changes in the catalytic behavior are ascribed to alloying
effect, especially because a considerable degree of Pt–Au mixing was achieved in the bimetallic samples. It appeared that
by introducing very small amount of gold (10 at.%) to platinum, the catalytic activity is increased. It is argued that the
occurrence of this moderate synergistic effect is associated with a decreased tendency of surface chloriding when platinum
is alloyed with gold.
Zbigniew Kowalczyk—deceased. 相似文献
10.
Some photon interaction parameters such as mass attenuation coefficient, effective atomic number, half value layer, mean free path and electron density for 15ZnO–(17.5–x)Al2O3–xFe2O3–67.5P2O5 glass system (x = 0, 7.5, 12.5, 17.5) and 15ZnO–(25–x)Al2O3–xFe2O3–60P2O5 glass system (x = 0, 25) have been investigated in the photon energy range of 1 keV to 100 GeV. It has been observed that all the photon interaction parameters for the selected glass systems vary with the photon energy. Among the selected glass systems, the sample 15ZnO–25Fe2O3–60P2O5 glass system shows maximum values for mass attenuation coefficients, effective atomic numbers, electron densities and minimum values for mean free path and half value layer in the entire energy grid. 相似文献
11.
Ultrafast pump-probe and transient photoluminescence spectroscopy were used to investigate carrier dynamics in β-Ga2O3 nanowires converted to β-Ga2O3/Ga2S3 under H2S between 400 to 600 °C. The β-Ga2O3 nanowires exhibited broad blue emission with a lifetime of 2.4 ns which was strongly suppressed after processing at 500–600 °C giving rise to red emission centered at 680 nm with a lifetime of 19 μs. Differential absorption spectroscopy reveals that state filling occurs in states located below the conduction band edge before sulfurization, but free carrier absorption is dominant in the β-Ga2O3/Ga2S3 nanowires processed at 500 to 600 °C for probing wavelengths >500 nm related to secondary excitation of the photo-generated carriers from the mid-gap states into the conduction band of Ga2S3. 相似文献
12.
Lianwei Shan Jun Ding Wenli Sun Zhidong Han Liguo Jin 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(6):1750-1759
To enhance the photocatalytic activity of monoclinic scheelite (ms) BiVO4 for dye degradation, the heterostructured core (BiVO4)/shell (BiVO4:Eu3+) samples were synthesized by sol–gel method. The samples were characterized by UV–Vis diffuse reflectance spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). The results reveal that as-synthesized photocatalysts are characteristic of ms core/shell structure, responsive to visible light. The XPS spectra confirm that the doped Eu3+ mainly distributed in the outside layer of BiVO4 particle. The valence band (VB) spectra indicate the shell (BiVO4:Eu3+) exhibits a high carrier mobility. The core/shell photocatalysts showed higher photocatalytic activity than pure BiVO4 through degrading Rhodamine B and Methylene blue. The better performance of core/shell heterojunction mainly results from that the Eu3+ ions selectively present on shell layer, increasing the VB value of shell layer (forming a interface electric field with core) and carrier mobility. It is considered that the half-filled 7f–electron configuration of Eu3+ can improve the electron trapping and transfer. Besides, the low PL intensity and high SBET of BiVO4/BiVO4:Eu3+ contribute to enhanced photocatalytic performances. 相似文献
13.
S. V. Mulevanov V. M. Nartsev A. N. Trofimov O. F. Beinarovich I. N. Gavrikova 《Glass Physics and Chemistry》2017,43(2):188-190
It is shown that the phase heterogeneity of SiO2–Na2O–Al2O3 glass has a liquation and crystallization nature, the balance between which is determined by the conditions of their synthesis. An increase in the aluminum oxide content decreases the number of liquation and crystallization sites, and also the linear sizes of the crystalline formations without eliminating the phase separation due to the liquation. The area of metastable immiscibility in the SiO2–Na2O–Al2O3 system, which is determined by scanning electron microscopy, is probably wider than the area detected by the optical methods. 相似文献
14.
E. A. Buluchevskii E. D. Fedorova A. V. Lavrenov M. V. Zhuravleva 《Catalysis in Industry》2018,10(2):118-125
The effect of the hydroisomerization conditions of the benzene-containing fraction of catalytic reforming gasoline on the yield and composition of products is studied on Pt/B2O3–Al2O3 and Pt/WO3–Al2O3 catalysts. These catalysts allow benzene to be completely removed from the raw material. At the same time, the greatest yields of liquid products are obtained with minimal losses of the octane number at 2 MPa, a mass feedstock hourly space velocity (MFHSV) of 2 h?1, and 325°C: 96.3 and 95.4 wt % on Pt/B2O3–Al2O3 and Pt/WO3–Al2O3 catalysts, respectively. The activity of the catalysts is maintained for 100 h during their operation. 相似文献
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Najla Karaa Besma Hamdi Abderrazek Oueslati Abdelhamid Ben Salah Ridha Zouari 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(4):746-754
The ionic salt [2(C5H6N2Cl)+], [CuCl4]2? complex of copper(II) has been synthesized and characterized. The X-ray diffraction analysis with a single crystal of this compound showed that the title compound (4-amino-2-chloropyridinium)2CuCl4 [(CAP)2CuCl4], crystallized at room temperature in the monoclinic system, space group C2/c (N°.15) and the following : a = 16.0064 (2) Å; b = 7.7964 (10) Å; c = 14.7240 (2) Å; β = 102.497 (10)°; V = 1793.91 (4) Å3 and Z = 4. The structure was solved by using 1,589 independent reflections down to R value of 0.021. The unit cell is made up of tetrachlorocuprate(II) anions and 4-amino-2-chloropyridinium cations linked together by an extensive hydrogen bond network of types N–H···Cl (N: pyridinium) and N–H···Cl (N: amine), and cation-lone pair of nitrogen element interactions. Solid state NMR spectra showed one and five isotropic resonances, 63Cu and 13C, respectively, confirming the solid state structure determined by X-ray diffraction. Impedance spectroscopy study, reported for single crystal, revealed that the conduction in the material was due to a hopping process. This work aims to reveal the thermal properties of a new copper(II) based organic–inorganic hybrid and the conductivity properties that these compounds exhibit. 相似文献
17.
L. V. Morozova M. V. Kalinina T. V. Khamova E. A. Vasil’eva O. A. Shilova 《Glass Physics and Chemistry》2016,42(4):408-413
The results of the studies of the process of fabricating ceramic filtration membranes in the system ZrO2(Y2O3)–Al2O3 are presented. The phase compositions of the precursor powders and sintered ceramics have been investigated and their porous structures have been determined. Two stages of the implementation of the technology were demonstrated: fabrication of substrates with an open porosity ranging from 20 to 47% and pore sizes in the 100–300 nm range, as well as the deposition of nanocrystalline aluminum oxide layers on them. It has been established that the pore size distribution in the membrane layer of α-Al2O3 is unimodal (from 30 to 100 nm). 相似文献
18.
F. Lian M. Gao W. H. Qiu P. Axmann M. Wohlfahrt-Mehrens 《Journal of Applied Electrochemistry》2012,42(6):409-417
With the aim of achieving a high-performance 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2 material, a series of 0.5Li2MnO3·0.5LiMn
x
Ni
y
Fe(1−x−y)O2 (0.3 ≤ x ≤ 0.5, 0.4 ≤ y ≤ 0.5) samples with low Fe content was synthesized via coprecipitation of carbonates. Its crystal structure and electrochemical
performance were characterized by means of powder X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron
spectroscopy, galvanostatic charge/discharge testing, cyclic voltammetry, and electrochemical impedance spectra. Rietveld
refinements with a model integrating R
[`3] \overline{3}
m and Fm
[`3] \overline{3}
m indicate that a low concentration of Fe incorporated in 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2 decrease a disordered cubic domain of the composite structure. The preferential distribution of Fe in cubic rock-salt contributes
to an unimaginable decrease of c-axis parameter of the predominant layered structure as the Fe content increases. Moreover, including Fe as a dopant can kinetically
improve crystallization and also change the ratio of Mn3+/Mn4+ and Ni3+/Ni2+. As a result, 0.5Li2MnO3·0.5LiMn0.4Ni0.5Fe0.1O2 exhibits lower Warburg impedance and higher reversible capacity than the undoped material. 相似文献
19.
Idris Kabalci Erkan Koc Sirri Semih Ozturk 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(3):788-794
Oxide based optical glass materials has important potential material in many applications from fiber optic to sensor due to the high transparency and amourphous structures. The objective of this study is to synthesize the novel optical glass materials based on the bismuth and aluminum contents to be able to determine the physical, chemical and mechanical properties by considering the systematic experimental steps. In this study, Bi2O3–Al2O3 based tellurite optical glasses have been prepared by using conventional melt quenching method as a function of the both Bi2O3 and Al2O3 compositions. There is a strong interactions between the glass former and modifier ions that might effect on the structure and mechanical properties. During the experimental steps, thermal, structural and mechanical properties of the prepared glass materials have been determined considering the DTA/DSC, FT-IR spectroscopy, SEM and Vicker’s hardness techniques, respectively. Thermal parameters, like glass transition, Tg, onset, Tx, crystallization, Tp, and melting, Tm, temperatures were obtained by using DTA scan. 相似文献
20.
Vapor–liquid equilibria of binary components of the BrCF2COOCH3–CF3COOH–BrCF2COOH–CF3COOCH3 quaternary system have been studied experimentally at constant pressure. The experiments have been carried out on a modified Sventoslavskii ebulliometer. Using the Aspen Plus software package, the appropriate models have been selected and the vapor–liquid equilibria for six binary systems have been simulated. 相似文献