A combined EDTA-citrate complexing method was developed for the easy preparation of mixed oxygen-ionic and electronic conducting dense ceramic membrane for oxygen separation. The nea method takes the advantage of lowe...A combined EDTA-citrate complexing method was developed for the easy preparation of mixed oxygen-ionic and electronic conducting dense ceramic membrane for oxygen separation. The nea method takes the advantage of lower calcination temperature for phase formation. lower membrane sintering temperature and higher relative density over the standard ceramic method.展开更多
A novel zirconium-based membrane material of BaCo0.4Fe0.4Zr0.2O3-6 with cubic perovskite structure was synthesized for the first time through a method of citric and EDTA acid combined complexes. The structural stabili...A novel zirconium-based membrane material of BaCo0.4Fe0.4Zr0.2O3-6 with cubic perovskite structure was synthesized for the first time through a method of citric and EDTA acid combined complexes. The structural stability was characterized by XRD, O-2-TPD and H-2-TPR techniques respectively. The high oxygen permeation flux of 0.873 mL/cm(2) min at 950 degreesC was obtained under He/Air gradient. Meanwhile, the single activation energy for oxygen permeation and the long-term steady operation of 200 h at 800 degreesC were achieved.展开更多
A novel silicon-on-insulator (SOI) high-voltage device based on epitaxy-separation by implantation oxygen (SIMOX) with a partial buried n+-layer silicon-on-insulator (PBN SOI) is proposed in this paper. Based o...A novel silicon-on-insulator (SOI) high-voltage device based on epitaxy-separation by implantation oxygen (SIMOX) with a partial buried n+-layer silicon-on-insulator (PBN SOI) is proposed in this paper. Based on the proposed expressions of the vertical interface electric field, the high concentration interface charges which are accumu- lated on the interface between top silicon layer and buried oxide layer (BOX) effectively enhance the electric field of the BOX (EI), resulting in a high breakdown voltage (BV) for the device. For the same thicknesses of top silicon layer (10 μm) and BOX (0.375 μm), the EI and BV of PBN SOI are improved by 186.5% and 45.4% in comparison with those of the conventional SOI, respectively.展开更多
A novel cobalt-free perovskite based on Ba0.5Sr0.5Fe0.8Zn0.2O3-δ (BSFZ) were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray di...A novel cobalt-free perovskite based on Ba0.5Sr0.5Fe0.8Zn0.2O3-δ (BSFZ) were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction (HTXRD). The thermal expansion coefficient of BSFZ is 10.5×10^-6 K^-1, which is lower than that of cobalt-based perovskite materials. The BSFZ membrane was also used to construct reactors for the partial oxidation of methane (POM) to syngas. Results show that the BSFZ membrane can be operated for the POM reaction for more than 100 h without any fractures. The CO selectivity of 97% is obtained. The steady oxygen permeation flux reaches around 2.5 mL/min cm^2 during POM reaction.展开更多
Perovskite-type a0.5Sr0.5Co0.8Fe0.1R0.1O3-δ (R=Al, Mn, Fe, Ce, Cr, Ni, Co) oxide membranes were ex- ploited and synthesized. Oxygen behavior, order-disorder transition and phase stability of these composite oxides ...Perovskite-type a0.5Sr0.5Co0.8Fe0.1R0.1O3-δ (R=Al, Mn, Fe, Ce, Cr, Ni, Co) oxide membranes were ex- ploited and synthesized. Oxygen behavior, order-disorder transition and phase stability of these composite oxides were investigated by combined analysis of X-ray diffraction (XRD), temperature programmed desorp- tion (TPD), thermogravimetric-differential thermal analysis (TG-DTA). Oxygen permeation through these membranes was studied by the gas chromatography (GC) method using a high-temperature permeation cell in a wide temperature range from 700 to 950℃. High permeation fluxes were observed for these materials. The high permeation flux was about 3.19 ml.min-l.cm-2 under air/He gradients at 950℃, which was achieved for a0.5Sr0.5Co0.8Fe0.1R0.1O3-δ(BSCFNiO) membrane. The results of analysis showed no phase transition for BSCFNiO oxide with increasing temperature and XRD pattern of this material after O2-TPD indicated to sustain a pure perovskite structure after oxygen permeation process.展开更多
In the field of modern hydrogen energy,obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems.Developing solid oxide fuel cells(SOFC)and catalytic membr...In the field of modern hydrogen energy,obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems.Developing solid oxide fuel cells(SOFC)and catalytic membranes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems.In this work,the authors’recent studies in this field are reviewed;the fundamentals of developing materials for SOFC cathodes and oxygen separation membranes’permselective layers based on research of their oxygen mobility and surface reactivity are presented.Ruddlesden-Popper phases Ln_(2-x)Ca_(x)NiO_(4+δ)(LnCNO)and perovskite-fluorite nanocomposites PrNi_(0.5)Co_(0.5)O_(3-δ)-Ce_(0.9)Y_(0.1)O_(2-δ)(PNC-YDC)were studied by isotope exchange of oxygen with C_(18)O_(2)and^(18)O_(2)in flow and closed reactors.For LnCNO a high oxygen mobility was shown(D*~10^(-7)cm^(2)/s at 700℃),being provided by the cooperative mechanism of oxygen migration involving both regular and highly-mobile interstitial oxygen.For PNC-YDC dominated a wide fast diffusion channel via fluorite phase and interphases due to features of the redistribution of cations resulting in superior oxygen mobility(D*~10^(-8)cm^(2)/s at 700℃).After optimization of composition and nanodomain structure of these materials,as cathodes of SOFC they provided a high power density,while for asymmetric supported oxygen separation membranes-a high oxygen permeability.展开更多
This paper presents a novel method that uses the interception effect of gradient magnetic field on oxygen molecules to realize enrichment.The use of two opposite magnetic poles of two magnets at a certain distance for...This paper presents a novel method that uses the interception effect of gradient magnetic field on oxygen molecules to realize enrichment.The use of two opposite magnetic poles of two magnets at a certain distance forms a magnetic space having a field intensity gradient near its borders.When air injected into the magnetic space outflows from the magnetic space via its borders,oxygen molecules in the air will experience the interception effect of the gradient magnetic field,but nitrogen molecules will outflow from the magnetic space without hindrance.Thus,continuous oxygen enrichment is realized.The enrichment degree of oxygen reaches 0.65%when the inlet and outlet air flows are 40 mL/min and 20 mL/min,respectively,and the gas temperature is 298 K and the maximal product of magnetic flux density and its gradient is 563 T2/m(the distance between two magnetic poles is 1 mm).When the gas temperature rises to 343 K,the enrichment degree drops to 0.32%;and when the maximal product of magnetic flux density and field intensity gradient drops to 101 T2/m(the distance between two magnetic poles is 4 mm),the enrichment degree drops to 0.23%.The experimental results show that there is an optimal ratio between the inlet air flow and the outlet air flow.Under the experimental conditions in this paper,the value is about 2.0.It is demonstrated that the method presented in this paper can continuously enrich oxygen and has a higher enrich-ment degree than other oxygen-enrichment methods using magnetic separation.展开更多
The change of bubbles and the position of the tuyere in an oxygen coal combustion melting and separating furnace affect the flow and splash behavior of the molten pool.To analyze this problem further,a three-dimension...The change of bubbles and the position of the tuyere in an oxygen coal combustion melting and separating furnace affect the flow and splash behavior of the molten pool.To analyze this problem further,a three-dimensional numerical simulation method was used to explore the behavior and change of the flow field inside the molten pool during double-row tuyere injection.In addition,the arrangement of the tuyere was changed for a more detailed understanding of the internal phase distribution and splashing in a molten pool.The results indicated that under three-dimensional numerical simulation conditions,bubbles rise after leaving the tuyere and break on the surface of the molten pool,which results in certain fluctuations in the nearby melt.During the injection process of the tuyere,the meteorological accumulation in the middle part of the molten pool formed part of the foam slag because of the influence of surface tension.When the layout of the upper and lower exhaust tuyeres was changed from staggered to symmetrical,or when the spacing of the upper and lower exhaust tuyeres changed,it had an effect on the phase distribution and splash behavior.展开更多
Partial oxidation of methane(POM) co-fed with CO_2 to syngas in a novel catalytic BaCo_(0.6)Fe_(0.2)Ta_(0.2)O_(3-δ) oxygen permeable membrane reactor was successfully reported.Adding CO_2 to the partial oxi...Partial oxidation of methane(POM) co-fed with CO_2 to syngas in a novel catalytic BaCo_(0.6)Fe_(0.2)Ta_(0.2)O_(3-δ) oxygen permeable membrane reactor was successfully reported.Adding CO_2 to the partial oxidation of methane reaction not only alters the ratio of CO/H_2,but also increases the oxygen permeation flux and CH_4 conversion.Around 96%CH_4 conversion with more than 93%CO_2 conversion and 100%CO selectivity is achieved,which shows an excellent reaction performance.A steady oxygen permeation flux of 15 mL/(cm^2 min) is obtained during the 100-h operation,which shows good stability as well.展开更多
基金the National Natural Science Foundation of China (Grant No. 59789201), the National Advanced Materials Committee of China (Grant
文摘A combined EDTA-citrate complexing method was developed for the easy preparation of mixed oxygen-ionic and electronic conducting dense ceramic membrane for oxygen separation. The nea method takes the advantage of lower calcination temperature for phase formation. lower membrane sintering temperature and higher relative density over the standard ceramic method.
基金This work was supported by the National Advanced Materials Committee(Grant No.715-006-0122)the Ministry of Science and Technology of China(G1999022401)the National Natural Science Foundation of China(Grant No.59789201).
文摘A novel zirconium-based membrane material of BaCo0.4Fe0.4Zr0.2O3-6 with cubic perovskite structure was synthesized for the first time through a method of citric and EDTA acid combined complexes. The structural stability was characterized by XRD, O-2-TPD and H-2-TPR techniques respectively. The high oxygen permeation flux of 0.873 mL/cm(2) min at 950 degreesC was obtained under He/Air gradient. Meanwhile, the single activation energy for oxygen permeation and the long-term steady operation of 200 h at 800 degreesC were achieved.
基金supported by the Natural Science Foundation of Chongqing Science and Technology Commission (CQ CSTC) of China (Grant No.cstcjjA40008)
文摘A novel silicon-on-insulator (SOI) high-voltage device based on epitaxy-separation by implantation oxygen (SIMOX) with a partial buried n+-layer silicon-on-insulator (PBN SOI) is proposed in this paper. Based on the proposed expressions of the vertical interface electric field, the high concentration interface charges which are accumu- lated on the interface between top silicon layer and buried oxide layer (BOX) effectively enhance the electric field of the BOX (EI), resulting in a high breakdown voltage (BV) for the device. For the same thicknesses of top silicon layer (10 μm) and BOX (0.375 μm), the EI and BV of PBN SOI are improved by 186.5% and 45.4% in comparison with those of the conventional SOI, respectively.
基金supported by Program for New Century Excellent Talents in Chinese Ministry of Education(No.NECT-07-0307)Natural Science Foundation of Guangdong province(No.7300769)+1 种基金Fok Ying Tung Education Foundation(No.114019)New Teacher Fund of Ministry of Education of China(No.20070561032).
文摘A novel cobalt-free perovskite based on Ba0.5Sr0.5Fe0.8Zn0.2O3-δ (BSFZ) were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction (HTXRD). The thermal expansion coefficient of BSFZ is 10.5×10^-6 K^-1, which is lower than that of cobalt-based perovskite materials. The BSFZ membrane was also used to construct reactors for the partial oxidation of methane (POM) to syngas. Results show that the BSFZ membrane can be operated for the POM reaction for more than 100 h without any fractures. The CO selectivity of 97% is obtained. The steady oxygen permeation flux reaches around 2.5 mL/min cm^2 during POM reaction.
文摘Perovskite-type a0.5Sr0.5Co0.8Fe0.1R0.1O3-δ (R=Al, Mn, Fe, Ce, Cr, Ni, Co) oxide membranes were ex- ploited and synthesized. Oxygen behavior, order-disorder transition and phase stability of these composite oxides were investigated by combined analysis of X-ray diffraction (XRD), temperature programmed desorp- tion (TPD), thermogravimetric-differential thermal analysis (TG-DTA). Oxygen permeation through these membranes was studied by the gas chromatography (GC) method using a high-temperature permeation cell in a wide temperature range from 700 to 950℃. High permeation fluxes were observed for these materials. The high permeation flux was about 3.19 ml.min-l.cm-2 under air/He gradients at 950℃, which was achieved for a0.5Sr0.5Co0.8Fe0.1R0.1O3-δ(BSCFNiO) membrane. The results of analysis showed no phase transition for BSCFNiO oxide with increasing temperature and XRD pattern of this material after O2-TPD indicated to sustain a pure perovskite structure after oxygen permeation process.
基金the Russian Science Foundation(Project 16-13-00112)the budget project#AAAA-A17-117041110045-9 for Boreskov Institute of Catalysis is gratefully acknowledged.
文摘In the field of modern hydrogen energy,obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems.Developing solid oxide fuel cells(SOFC)and catalytic membranes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems.In this work,the authors’recent studies in this field are reviewed;the fundamentals of developing materials for SOFC cathodes and oxygen separation membranes’permselective layers based on research of their oxygen mobility and surface reactivity are presented.Ruddlesden-Popper phases Ln_(2-x)Ca_(x)NiO_(4+δ)(LnCNO)and perovskite-fluorite nanocomposites PrNi_(0.5)Co_(0.5)O_(3-δ)-Ce_(0.9)Y_(0.1)O_(2-δ)(PNC-YDC)were studied by isotope exchange of oxygen with C_(18)O_(2)and^(18)O_(2)in flow and closed reactors.For LnCNO a high oxygen mobility was shown(D*~10^(-7)cm^(2)/s at 700℃),being provided by the cooperative mechanism of oxygen migration involving both regular and highly-mobile interstitial oxygen.For PNC-YDC dominated a wide fast diffusion channel via fluorite phase and interphases due to features of the redistribution of cations resulting in superior oxygen mobility(D*~10^(-8)cm^(2)/s at 700℃).After optimization of composition and nanodomain structure of these materials,as cathodes of SOFC they provided a high power density,while for asymmetric supported oxygen separation membranes-a high oxygen permeability.
基金supported by the Key Project of Beijing Municipal Committee of Education(Grant No.00020)the Foundation Project of University of Science and Technology Beijing(Grant No.20040600290),China.
文摘This paper presents a novel method that uses the interception effect of gradient magnetic field on oxygen molecules to realize enrichment.The use of two opposite magnetic poles of two magnets at a certain distance forms a magnetic space having a field intensity gradient near its borders.When air injected into the magnetic space outflows from the magnetic space via its borders,oxygen molecules in the air will experience the interception effect of the gradient magnetic field,but nitrogen molecules will outflow from the magnetic space without hindrance.Thus,continuous oxygen enrichment is realized.The enrichment degree of oxygen reaches 0.65%when the inlet and outlet air flows are 40 mL/min and 20 mL/min,respectively,and the gas temperature is 298 K and the maximal product of magnetic flux density and its gradient is 563 T2/m(the distance between two magnetic poles is 1 mm).When the gas temperature rises to 343 K,the enrichment degree drops to 0.32%;and when the maximal product of magnetic flux density and field intensity gradient drops to 101 T2/m(the distance between two magnetic poles is 4 mm),the enrichment degree drops to 0.23%.The experimental results show that there is an optimal ratio between the inlet air flow and the outlet air flow.Under the experimental conditions in this paper,the value is about 2.0.It is demonstrated that the method presented in this paper can continuously enrich oxygen and has a higher enrich-ment degree than other oxygen-enrichment methods using magnetic separation.
基金supported by the National Key R&D Program of China(2017YFB0603800 and 2017YFB0603802).
文摘The change of bubbles and the position of the tuyere in an oxygen coal combustion melting and separating furnace affect the flow and splash behavior of the molten pool.To analyze this problem further,a three-dimensional numerical simulation method was used to explore the behavior and change of the flow field inside the molten pool during double-row tuyere injection.In addition,the arrangement of the tuyere was changed for a more detailed understanding of the internal phase distribution and splashing in a molten pool.The results indicated that under three-dimensional numerical simulation conditions,bubbles rise after leaving the tuyere and break on the surface of the molten pool,which results in certain fluctuations in the nearby melt.During the injection process of the tuyere,the meteorological accumulation in the middle part of the molten pool formed part of the foam slag because of the influence of surface tension.When the layout of the upper and lower exhaust tuyeres was changed from staggered to symmetrical,or when the spacing of the upper and lower exhaust tuyeres changed,it had an effect on the phase distribution and splash behavior.
基金the financial support by Natural Science Foundation of China(Nos.U0834004 and 20936001)the Science-Technology Plan of Guangzhou City(No.2009J1-C511-1)the Fundamental Research Funds for the Central Universities,SCUT(No.2009220038)
文摘Partial oxidation of methane(POM) co-fed with CO_2 to syngas in a novel catalytic BaCo_(0.6)Fe_(0.2)Ta_(0.2)O_(3-δ) oxygen permeable membrane reactor was successfully reported.Adding CO_2 to the partial oxidation of methane reaction not only alters the ratio of CO/H_2,but also increases the oxygen permeation flux and CH_4 conversion.Around 96%CH_4 conversion with more than 93%CO_2 conversion and 100%CO selectivity is achieved,which shows an excellent reaction performance.A steady oxygen permeation flux of 15 mL/(cm^2 min) is obtained during the 100-h operation,which shows good stability as well.