In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA...In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA-5118.For acetaldehyde in acetone with ferric ion as catalyst,the optimized process conditions were presented. The main factors influencing the yield,selectivity and conversion are residence time,temperature and acetaldehyde concentration,respectively.The temperature range checked is from 30 to 65℃.High yield of 81.53%with high se- lectivity of 91.84%can be obtained at higher temperature of 55℃when the residence time is 5.5min and the acet- aldehyde concentration is 9.85%（by mass）.And there is a critical acetaldehyde concentration point（Cccp）between 18%and 19.5%（by mass）.At temperature less than 55℃,the highest yield to peracetic acid at each temperature level increases with temperature when the acetaldehyde concentration is below Cccp and decreases with temperature when the acetaldehyde concentration is above Cccp.展开更多
In this paper, a kinetics model for the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid catalyzed by cobalt-manganese-bromide is proposed. The effects of the reaction tempe...In this paper, a kinetics model for the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid catalyzed by cobalt-manganese-bromide is proposed. The effects of the reaction temperature, catalyst concentration and ratio of catalyst on the lime evolution of the experimental concentration for the constituents including raw material, intermediates and product are investigated. The model parameters are determined in a nonlinear optimization, minimizing the difference between the simulated and experimental time evolution of the product composition obtained in a semi-batch oxidation reactor where the gas and liquid phase were well nuxed. The kinetics data demonstrate that the model is suitable to the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid.展开更多
For the goal of sulfur recovery, most methods are aimed at the tail gas with high-concentration H2S, but few effective methods are used for low-concentration H2S. In this work, Low-concentration H2S could be purified ...For the goal of sulfur recovery, most methods are aimed at the tail gas with high-concentration H2S, but few effective methods are used for low-concentration H2S. In this work, Low-concentration H2S could be purified well by liquid phase catalytic oxidation (LCO), and the sulfur resource could also be recovered. The absorption solution was prepared by FeCl3 and sulfosalicylic acid. Under the experimental conditions, the conversion of H2S to S could be maintained above 94% at 60 ℃. In order to enhance the economical efficiency of LCO method, the absorption solution was modified by doping Ce, and a series of experiments were designed to investigate its performance. The results showed that the conversion of H2S had no obvious improvement, but above 98% conversion could be gained at 60 ℃, and the H2S conversion rate was enhanced. The optimum addition quality of Ce(NO3)3 was 0.08 g to 50 ml Fe3+ solution.展开更多
YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios were deposited on superalloy Inconel 600 by electrophoretic deposition（EPD） technique, followed by sintering in CH_4 atmosphere at 1 100 ℃for 2 h ...YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios were deposited on superalloy Inconel 600 by electrophoretic deposition（EPD） technique, followed by sintering in CH_4 atmosphere at 1 100 ℃for 2 h and isothermally oxidation at 1000 ℃ for 50 h. After sintering at 1100 ℃ for 2 h in CH_4 atmosphere, besides ZrC and t-ZrO_2 phases, the phase constitutes of Ni：Al mole ratios with 1：3, 1：2, and 1：1 were（Zr, Al）C, AlNi_3 and Ni phases, respectively. A remarkable difference in the oxidation behaviors of YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios was observed. For YSZ（Ni：Al=1：3） coated sample, oxidation at 1000 ℃ causes decomposition of the（Zr,Al）C solid solution to metallic Al, and then most of the Al is oxidized to Al_2O_3. For the YSZ（Ni：Al=1：2） coated sample, oxidation at 1000 ℃ mainly causes decomposition of the AlNi_3 phase. For YSZ（Ni：Al=1：1） coated sample, after oxidation at 1000 ℃, most of the Ni is oxidized to Ni O phase, and tolerated 50 h of oxidation and finally cracked and spalled from the specimen. YSZ（Ni：Al=1：3） and YSZ（Ni：Al=1：2） coated samples show superior oxidation resistance than that of YSZ coating. The different oxidation resistance mechanisms of YSZ/（Ni, Al） composite coatings sintered in CH_4 atmosphere were discussed.展开更多
Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and su...Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and sulfur capacity of the composite solution was about 3 g/L.The results show that purification efficiency was affected by catalyst addition,pH,experimental temperature,and sulfur capacity.The parameters effects on catalytic oxidation were studied,and the optimized conditions were that Fe3+ concentration 0.08 mg/L,reaction temperature 70°C,pH 9.0,with a absorption solution volume of 50 mL,a gas flow rate 200 mL/min,and H2S mass concentration of 1.58-2.02 mg/m3.展开更多
The mechanical properties and oxidation resistance of two nickel-based superalloys with and without oxide dispersion strengthened(ODS)phases at different temperatures were studied.The microstructure was investigated b...The mechanical properties and oxidation resistance of two nickel-based superalloys with and without oxide dispersion strengthened(ODS)phases at different temperatures were studied.The microstructure was investigated by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and transmission electron microscopy(TEM).The results show that the yield strength of the samples with and without ODS phases at room temperature is 1020 and 324 MPa,respectively.The yield strength model was constructed,and it is found that the contribution of grain boundary strengthening,dislocation strengthening and nanoparticle strengthening of nickel-based ODS superalloy exceeds 83%.As the temperature increases,grain boundary sliding and migration decrease the strength of sample but improve its ductility.Oxidation hinders the ductility of sample and intensifies its fracture,and the maximum elongation of nickel-based ODS superalloy at 800℃ is 47.3%.展开更多
Thermal barrier coatings（TBCs） protection is widely used to prolong the lifetime of turbine components.The outermost layer of TBCs is ceramic layer, whose function is heat insulation, and the main composition of the...Thermal barrier coatings（TBCs） protection is widely used to prolong the lifetime of turbine components.The outermost layer of TBCs is ceramic layer, whose function is heat insulation, and the main composition of the ceramic layer is ZrO2. In this study, the micro-Zr02 and the nano-ZrO2 doped with 10 wt% CeO2 as well as microZrO2 and nano-ZrO2 were prepared by air plasma spraying（APS） to study the advantages of the addition of rare earth element. The effect of CeO2 on the phase transformation of ZrO2 was studied. The results show that there are few cracks in micro-and nano-ZrO2 doped with 10 wt% CeO2,and rare earth oxides can affect the phase transformation significantly. The morphologies, hardness and elastic modulus of the four ceramic layers were also discussed.展开更多
The effects of MgO and TiO_2 on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed b...The effects of MgO and TiO_2 on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO_2 content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO_2 contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO_2 content.展开更多
The non-isothermal oxidation experiments of ilmenite concentrate were carried out at various heating rates under air atmosphere by thermogravimetry.The oxidation kinetic model function and kinetic parameters of appare...The non-isothermal oxidation experiments of ilmenite concentrate were carried out at various heating rates under air atmosphere by thermogravimetry.The oxidation kinetic model function and kinetic parameters of apparent activation energy（Ea）were evaluated by Málek and Starink methods.The results show that under air atmosphere,the oxidation process of ilmenite concentrate is composed of three stages,and the chemical reaction（G（α）=1-（1-α）~2,whereαis the conversion degree）plays an important role in the whole oxidation process.At the first stage（α=0.05-0.30）,the oxidation process is controlled gradually by secondary chemical reaction with increasing conversion degree.At the second stage（α=0.30-0.50）,the oxidation process is completely controlled by the secondary chemical reaction（G（α）=1-（1-α）~2）.At the third stage（α=0.50-0.95）,the secondary chemical reaction weakens gradually with increasing conversion degree,and the oxidation process is controlled gradually by a variety of functions;the kinetic equations are G（α）=（1-α）^（-1）（β=10K·min^（-1）,whereβis heating rate）,G（α）=（1-α）^（-1/2）（β=15-20K·min^（-1））,and G（α）=（1-α）^（-2）（β=25K·min^（-1））,respectively.For the whole oxidation process,the activation energies follow a parabolic law with increasing conversion degree,and the average activation energy is 160.56kJ·mol^（-1）.展开更多
Many phases appear in BaLn 2Mn 2O 7 family (Ln=rare earth) belonging to one of the Ruddlesden-Popper type compounds, depending upon the experimental conditions such as heating conditions when prepared and compositi...Many phases appear in BaLn 2Mn 2O 7 family (Ln=rare earth) belonging to one of the Ruddlesden-Popper type compounds, depending upon the experimental conditions such as heating conditions when prepared and composition. Some of these phases were characterized by powder X-ray diffraction method using Rietveld analysis. These phases have only a little difference in crystal structure which has fundamentally K 2NiF 4 type structure, although the X-ray diffraction patterns are clearly different: a little deformation or tilting of the oxygen octahedron surrounding a central manganese ion composing the main frame of this structure induce these different diffraction patterns. Phase behavior of these compounds, mainly the detailed relation between various phases in BaTb 2Mn 2O 7, was refined including the data of high temperature X-ray diffractometry.展开更多
La（0.4）Sr（0.6）Co（0.2）Fe（0.7）Nb（0.1）O（3-δ）（LSCFN）was applied as both anode and cathode for symmetrical solid oxide fuel cells（SSOFCs）with zirconia based electrolyte.The cell with LSCFN electrode was fa...La（0.4）Sr（0.6）Co（0.2）Fe（0.7）Nb（0.1）O（3-δ）（LSCFN）was applied as both anode and cathode for symmetrical solid oxide fuel cells（SSOFCs）with zirconia based electrolyte.The cell with LSCFN electrode was fabricated by tape-casting and screen printing.Fabrication process was optimized firstly by comparing co-sintering and separate-sintering of electrode and electrolyte.To further improve the LSCFN electrode properties,oxygen ionic conductor of Gd（0.1）Ce（0.9）O（2-δ）（GDC）was added into the LSCFN electrode.The preferred composition of LSCFN-GDC composite electrode was found to be 1：1 in weight ratio with polarization resistance of 0.16Ωcm^2at 800~℃.The maximum power densities of LSCFN-GDC｜｜GDC/YSZ/GDC｜｜LSCFN-GDC tested in H2and CH4with 3%H2O were 395 m W cm^（-2）and 124 m W cm^（-2）at 850~？C,respectively,which were much higher than that of LSCFN｜｜GDC/YSZ/GDC｜｜LSCFN cells at same condition,possibly due to the extension of the triple phase boundary induced by the addition of GDC.The cell showed reasonable stability using H2and CH4with 3%H2O as fuels and no significant power output degradation was observed after total 200 h operation.展开更多
A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior ...A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-（tert-butoxy）-N-（3-carbamothioylphenyl）acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions（pH 6,flow rate 9 mL/min）,metal ions were retained on the column,then quantitatively eluted by HNO3solution（5 mL,3.0 mol/L）.The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL（Ni2＋） to0.63 ng/mL（Cu2＋）.The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.展开更多
Many researchers have studied on perovskite oxide for its unique structure.Perovskite oxides,ABO3-δ,with different A and B metals have shown wide applications in many fields,in particular solid oxide electrolysers.Sr...Many researchers have studied on perovskite oxide for its unique structure.Perovskite oxides,ABO3-δ,with different A and B metals have shown wide applications in many fields,in particular solid oxide electrolysers.SrFeO3-δ,typical perovskite oxides,in which iron is the mixed-valence cation with the capacity to change the chemical valence,have a wide range of oxygen nonstoichiometry.In this study,Sr（0.9）Fe（0.9）Zr（0.1）O3-δ（SFZO） is synthesized and then treated in 5%H2/Ar and air at high temperature,exhibiting excellent redox stability.Redox-stable structure,oxygen vacancy and electrical properties of SFZO are investigated.Steam electrolysis is then performed with SFZO cathode under 5%H2O/5%H2/Ar and 5%H2O/Ar atmospheres,respectively.The present results indicate that the SFZO is a novel promising cathode material for solid oxide steam electrolyser.展开更多
A series of Co/Mg-Al oxide samples, CoMgAl-x （x = （Mg ＋ Co）]AI molar ratio of 1-5）, were prepared by the self-combustion method followed by H2 reduction. The catalytic performance and stability of the samples wer...A series of Co/Mg-Al oxide samples, CoMgAl-x （x = （Mg ＋ Co）]AI molar ratio of 1-5）, were prepared by the self-combustion method followed by H2 reduction. The catalytic performance and stability of the samples were studied in dry reforming ofCH4. XRD and H2-TPR characterization results showed that the reduced CoMgAl-x samples mainly consisted of solid solution and spinel phases with cobalt particles. The spinel phases contained COB04 and ConMgl-nAl204 （0 〈 n 〈 1 ） varying with the （Mg ＋ Co）/AI ratio, The effect of （Mg ＋ Co）/A1 molar ratio on the catalytic behavior was investigated in detail and CoMgAI-3 exhibited the highest catalytic activity and stability among the catalysts studied.展开更多
P2-type layered Ni–Mn-based oxides are vital cathode materials for sodiumion batteries(SIBs)due to their high discharge capacity and working voltage.However,they suffer from the detrimental P2→O_(2) phase transition...P2-type layered Ni–Mn-based oxides are vital cathode materials for sodiumion batteries(SIBs)due to their high discharge capacity and working voltage.However,they suffer from the detrimental P2→O_(2) phase transition induced by the O^(2-)−O^(2-)−electrostatic repulsion upon high-voltage charge,which leads to rapid capacity fade.Herein,we construct a P2-type Ni–Mn-based layered oxide cathode with a core-shell structure(labeled as NM–Mg–CS).The P2-Na_(0.67)[Ni_(0.25)Mn_(0.75)]O_(2)(NM)core is enclosed by the robust P2-Na_(0.67)[Ni_(0.21)Mn_(0.71)Mg_(0.08)]O_(2)(NM–Mg)shell.The NM–Mg–CS exhibits the phase-transition-free character with mitigated volume change because the confinement effect of shell is conductive to inhibit the irreversible phase transition of the core material.As a result,it drives a high capacity retention of 81%after 1000 cycles at 5 C with an initial capacity of 78mA h/g.And the full cell with the NM–Mg–CS cathode and hard carbon anode delivers stable capacities over 250 cycles.The successful construction of the core-shell structure in P2-type layered oxides sheds light on the development of high-capacity and long-life cathode materials for SIBs.展开更多
Research topics and methods of green chemistry in chromate production are introduced in this paper. New original green chemical process of the heterogeneous reaction and separation system of liquid phase oxidation of ...Research topics and methods of green chemistry in chromate production are introduced in this paper. New original green chemical process of the heterogeneous reaction and separation system of liquid phase oxidation of chromite in molten salt of sodium hydroxide—one way separation in high concentration medium—metastable phase separation—carbonate recycle conversion has been developed. The green commercial process for comprehensive utilization of mineral resources—reactant recycle inside the process—zero emission was established.展开更多
文摘In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA-5118.For acetaldehyde in acetone with ferric ion as catalyst,the optimized process conditions were presented. The main factors influencing the yield,selectivity and conversion are residence time,temperature and acetaldehyde concentration,respectively.The temperature range checked is from 30 to 65℃.High yield of 81.53%with high se- lectivity of 91.84%can be obtained at higher temperature of 55℃when the residence time is 5.5min and the acet- aldehyde concentration is 9.85%（by mass）.And there is a critical acetaldehyde concentration point（Cccp）between 18%and 19.5%（by mass）.At temperature less than 55℃,the highest yield to peracetic acid at each temperature level increases with temperature when the acetaldehyde concentration is below Cccp and decreases with temperature when the acetaldehyde concentration is above Cccp.
文摘In this paper, a kinetics model for the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid catalyzed by cobalt-manganese-bromide is proposed. The effects of the reaction temperature, catalyst concentration and ratio of catalyst on the lime evolution of the experimental concentration for the constituents including raw material, intermediates and product are investigated. The model parameters are determined in a nonlinear optimization, minimizing the difference between the simulated and experimental time evolution of the product composition obtained in a semi-batch oxidation reactor where the gas and liquid phase were well nuxed. The kinetics data demonstrate that the model is suitable to the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid.
基金the Natural Science Foundation of Yunnan Province (2001E0011Q)the Science Foundation of The Education Department of Yunnan Province (0142111 and 07Z11402)
文摘For the goal of sulfur recovery, most methods are aimed at the tail gas with high-concentration H2S, but few effective methods are used for low-concentration H2S. In this work, Low-concentration H2S could be purified well by liquid phase catalytic oxidation (LCO), and the sulfur resource could also be recovered. The absorption solution was prepared by FeCl3 and sulfosalicylic acid. Under the experimental conditions, the conversion of H2S to S could be maintained above 94% at 60 ℃. In order to enhance the economical efficiency of LCO method, the absorption solution was modified by doping Ce, and a series of experiments were designed to investigate its performance. The results showed that the conversion of H2S had no obvious improvement, but above 98% conversion could be gained at 60 ℃, and the H2S conversion rate was enhanced. The optimum addition quality of Ce(NO3)3 was 0.08 g to 50 ml Fe3+ solution.
基金Funded by the Science and Technology Key Fund Project of Shanghai University of Engineering Science(cs1405015)the Graduate Research and Innovation Special Projects of Shanghai University of Engineering Science(15KY0501 and 14KY0515)
文摘YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios were deposited on superalloy Inconel 600 by electrophoretic deposition（EPD） technique, followed by sintering in CH_4 atmosphere at 1 100 ℃for 2 h and isothermally oxidation at 1000 ℃ for 50 h. After sintering at 1100 ℃ for 2 h in CH_4 atmosphere, besides ZrC and t-ZrO_2 phases, the phase constitutes of Ni：Al mole ratios with 1：3, 1：2, and 1：1 were（Zr, Al）C, AlNi_3 and Ni phases, respectively. A remarkable difference in the oxidation behaviors of YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios was observed. For YSZ（Ni：Al=1：3） coated sample, oxidation at 1000 ℃ causes decomposition of the（Zr,Al）C solid solution to metallic Al, and then most of the Al is oxidized to Al_2O_3. For the YSZ（Ni：Al=1：2） coated sample, oxidation at 1000 ℃ mainly causes decomposition of the AlNi_3 phase. For YSZ（Ni：Al=1：1） coated sample, after oxidation at 1000 ℃, most of the Ni is oxidized to Ni O phase, and tolerated 50 h of oxidation and finally cracked and spalled from the specimen. YSZ（Ni：Al=1：3） and YSZ（Ni：Al=1：2） coated samples show superior oxidation resistance than that of YSZ coating. The different oxidation resistance mechanisms of YSZ/（Ni, Al） composite coatings sintered in CH_4 atmosphere were discussed.
基金Project(2008ZX07105-002) supported by the Erhai Lake Project of National Science and Technology Major Project in the 11th Five years Plan of China
文摘Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and sulfur capacity of the composite solution was about 3 g/L.The results show that purification efficiency was affected by catalyst addition,pH,experimental temperature,and sulfur capacity.The parameters effects on catalytic oxidation were studied,and the optimized conditions were that Fe3+ concentration 0.08 mg/L,reaction temperature 70°C,pH 9.0,with a absorption solution volume of 50 mL,a gas flow rate 200 mL/min,and H2S mass concentration of 1.58-2.02 mg/m3.
基金supported by the National Natural Science Foundation of China(No.52271177)Leading Talents Project of Scientific and Technological Innovation in Hunan Province,China(No.2021RC4036)+1 种基金the Natural Science Foundation of Hunan Province,China(Nos.2023JJ50172,2020JJ6069)State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology,China。
文摘The mechanical properties and oxidation resistance of two nickel-based superalloys with and without oxide dispersion strengthened(ODS)phases at different temperatures were studied.The microstructure was investigated by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and transmission electron microscopy(TEM).The results show that the yield strength of the samples with and without ODS phases at room temperature is 1020 and 324 MPa,respectively.The yield strength model was constructed,and it is found that the contribution of grain boundary strengthening,dislocation strengthening and nanoparticle strengthening of nickel-based ODS superalloy exceeds 83%.As the temperature increases,grain boundary sliding and migration decrease the strength of sample but improve its ductility.Oxidation hinders the ductility of sample and intensifies its fracture,and the maximum elongation of nickel-based ODS superalloy at 800℃ is 47.3%.
基金financially supported by the National Natural Science Foundation of China(No.51371173)the Natural Science Foundation of Liaoning Province(No.2013024011)the Doctor Start-Up Fund of Liaoning Province(No.20121063)
文摘Thermal barrier coatings（TBCs） protection is widely used to prolong the lifetime of turbine components.The outermost layer of TBCs is ceramic layer, whose function is heat insulation, and the main composition of the ceramic layer is ZrO2. In this study, the micro-Zr02 and the nano-ZrO2 doped with 10 wt% CeO2 as well as microZrO2 and nano-ZrO2 were prepared by air plasma spraying（APS） to study the advantages of the addition of rare earth element. The effect of CeO2 on the phase transformation of ZrO2 was studied. The results show that there are few cracks in micro-and nano-ZrO2 doped with 10 wt% CeO2,and rare earth oxides can affect the phase transformation significantly. The morphologies, hardness and elastic modulus of the four ceramic layers were also discussed.
基金financial support by the Fundamental Research Funds for the Central Universities (No. N130602003)National High Technology Research and Development Program of China (No. 2012AA062302)the National Natural Science Foundation of China (No. 51574067)
文摘The effects of MgO and TiO_2 on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO_2 content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO_2 contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO_2 content.
基金supported by the National Natural Science Foundation of China(Grant No.51234010)Special Fund for Basic Scientific Research in Colleges and Universities of the Central Business (No.0903005203413)
文摘The non-isothermal oxidation experiments of ilmenite concentrate were carried out at various heating rates under air atmosphere by thermogravimetry.The oxidation kinetic model function and kinetic parameters of apparent activation energy（Ea）were evaluated by Málek and Starink methods.The results show that under air atmosphere,the oxidation process of ilmenite concentrate is composed of three stages,and the chemical reaction（G（α）=1-（1-α）~2,whereαis the conversion degree）plays an important role in the whole oxidation process.At the first stage（α=0.05-0.30）,the oxidation process is controlled gradually by secondary chemical reaction with increasing conversion degree.At the second stage（α=0.30-0.50）,the oxidation process is completely controlled by the secondary chemical reaction（G（α）=1-（1-α）~2）.At the third stage（α=0.50-0.95）,the secondary chemical reaction weakens gradually with increasing conversion degree,and the oxidation process is controlled gradually by a variety of functions;the kinetic equations are G（α）=（1-α）^（-1）（β=10K·min^（-1）,whereβis heating rate）,G（α）=（1-α）^（-1/2）（β=15-20K·min^（-1））,and G（α）=（1-α）^（-2）（β=25K·min^（-1））,respectively.For the whole oxidation process,the activation energies follow a parabolic law with increasing conversion degree,and the average activation energy is 160.56kJ·mol^（-1）.
文摘Many phases appear in BaLn 2Mn 2O 7 family (Ln=rare earth) belonging to one of the Ruddlesden-Popper type compounds, depending upon the experimental conditions such as heating conditions when prepared and composition. Some of these phases were characterized by powder X-ray diffraction method using Rietveld analysis. These phases have only a little difference in crystal structure which has fundamentally K 2NiF 4 type structure, although the X-ray diffraction patterns are clearly different: a little deformation or tilting of the oxygen octahedron surrounding a central manganese ion composing the main frame of this structure induce these different diffraction patterns. Phase behavior of these compounds, mainly the detailed relation between various phases in BaTb 2Mn 2O 7, was refined including the data of high temperature X-ray diffractometry.
基金supported by the National Natural Science Foundation of China (No. 51402355)Natural Science Foundation of Beijing Project (Nos. LJ201531 and 2154056)+1 种基金Shanxi Province Project (No. MD2014-08)Guangdong Project (No. 201460720100025)
文摘La（0.4）Sr（0.6）Co（0.2）Fe（0.7）Nb（0.1）O（3-δ）（LSCFN）was applied as both anode and cathode for symmetrical solid oxide fuel cells（SSOFCs）with zirconia based electrolyte.The cell with LSCFN electrode was fabricated by tape-casting and screen printing.Fabrication process was optimized firstly by comparing co-sintering and separate-sintering of electrode and electrolyte.To further improve the LSCFN electrode properties,oxygen ionic conductor of Gd（0.1）Ce（0.9）O（2-δ）（GDC）was added into the LSCFN electrode.The preferred composition of LSCFN-GDC composite electrode was found to be 1：1 in weight ratio with polarization resistance of 0.16Ωcm^2at 800~℃.The maximum power densities of LSCFN-GDC｜｜GDC/YSZ/GDC｜｜LSCFN-GDC tested in H2and CH4with 3%H2O were 395 m W cm^（-2）and 124 m W cm^（-2）at 850~？C,respectively,which were much higher than that of LSCFN｜｜GDC/YSZ/GDC｜｜LSCFN cells at same condition,possibly due to the extension of the triple phase boundary induced by the addition of GDC.The cell showed reasonable stability using H2and CH4with 3%H2O as fuels and no significant power output degradation was observed after total 200 h operation.
文摘A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-（tert-butoxy）-N-（3-carbamothioylphenyl）acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions（pH 6,flow rate 9 mL/min）,metal ions were retained on the column,then quantitatively eluted by HNO3solution（5 mL,3.0 mol/L）.The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL（Ni2＋） to0.63 ng/mL（Cu2＋）.The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.
基金Supported by the National Natural Science Foundation of China(91545123)and the Natural Science Foundation of Fujian Province(2016J01275)
文摘Many researchers have studied on perovskite oxide for its unique structure.Perovskite oxides,ABO3-δ,with different A and B metals have shown wide applications in many fields,in particular solid oxide electrolysers.SrFeO3-δ,typical perovskite oxides,in which iron is the mixed-valence cation with the capacity to change the chemical valence,have a wide range of oxygen nonstoichiometry.In this study,Sr（0.9）Fe（0.9）Zr（0.1）O3-δ（SFZO） is synthesized and then treated in 5%H2/Ar and air at high temperature,exhibiting excellent redox stability.Redox-stable structure,oxygen vacancy and electrical properties of SFZO are investigated.Steam electrolysis is then performed with SFZO cathode under 5%H2O/5%H2/Ar and 5%H2O/Ar atmospheres,respectively.The present results indicate that the SFZO is a novel promising cathode material for solid oxide steam electrolyser.
基金supported by the Ministry of Science and Technology(No.2009CB623506)the National Natural Science Foundation of China(No.21173050)Shanghai Leading Academic Discipline Project(No.B108)
文摘A series of Co/Mg-Al oxide samples, CoMgAl-x （x = （Mg ＋ Co）]AI molar ratio of 1-5）, were prepared by the self-combustion method followed by H2 reduction. The catalytic performance and stability of the samples were studied in dry reforming ofCH4. XRD and H2-TPR characterization results showed that the reduced CoMgAl-x samples mainly consisted of solid solution and spinel phases with cobalt particles. The spinel phases contained COB04 and ConMgl-nAl204 （0 〈 n 〈 1 ） varying with the （Mg ＋ Co）/AI ratio, The effect of （Mg ＋ Co）/A1 molar ratio on the catalytic behavior was investigated in detail and CoMgAI-3 exhibited the highest catalytic activity and stability among the catalysts studied.
基金supported by the National Natural Science Foundation of China(Nos.22121005 and 52072186)Open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering(No.JDSX2023003)+1 种基金the National Key Research and Development Program of China(Nos.2022YFB2402200 and 2019YFA0705600)the Fundamental Research Funds for the Central Universities of China(Nos.63233017,63231002,and 63231198).
文摘P2-type layered Ni–Mn-based oxides are vital cathode materials for sodiumion batteries(SIBs)due to their high discharge capacity and working voltage.However,they suffer from the detrimental P2→O_(2) phase transition induced by the O^(2-)−O^(2-)−electrostatic repulsion upon high-voltage charge,which leads to rapid capacity fade.Herein,we construct a P2-type Ni–Mn-based layered oxide cathode with a core-shell structure(labeled as NM–Mg–CS).The P2-Na_(0.67)[Ni_(0.25)Mn_(0.75)]O_(2)(NM)core is enclosed by the robust P2-Na_(0.67)[Ni_(0.21)Mn_(0.71)Mg_(0.08)]O_(2)(NM–Mg)shell.The NM–Mg–CS exhibits the phase-transition-free character with mitigated volume change because the confinement effect of shell is conductive to inhibit the irreversible phase transition of the core material.As a result,it drives a high capacity retention of 81%after 1000 cycles at 5 C with an initial capacity of 78mA h/g.And the full cell with the NM–Mg–CS cathode and hard carbon anode delivers stable capacities over 250 cycles.The successful construction of the core-shell structure in P2-type layered oxides sheds light on the development of high-capacity and long-life cathode materials for SIBs.
基金Special article from the First International Workshop on Green Chemistry, the University of ScienceTechnology of China, Hefei, China, May, 1998.+1 种基金Project supported by Chinese Academy of Sciences (No.KZ95T-05)the National Natural Science Foundation of
文摘Research topics and methods of green chemistry in chromate production are introduced in this paper. New original green chemical process of the heterogeneous reaction and separation system of liquid phase oxidation of chromite in molten salt of sodium hydroxide—one way separation in high concentration medium—metastable phase separation—carbonate recycle conversion has been developed. The green commercial process for comprehensive utilization of mineral resources—reactant recycle inside the process—zero emission was established.
