The three-way catalysts （TWCs） promoters Ce0.6Zr0.4- x TbxO2-y were prepared by sol-gel method. BET surface areas analysis indicated that an increase of the dopant Tb content from x = 0.05 to x = 0.15 favors an incr...The three-way catalysts （TWCs） promoters Ce0.6Zr0.4- x TbxO2-y were prepared by sol-gel method. BET surface areas analysis indicated that an increase of the dopant Tb content from x = 0.05 to x = 0.15 favors an increase of surface area from 66.8 to 80.4 m^2· g^-1 compared with the undoped sample Ce0 .6oZr0.40O2 65.1 m^2·g^- 1 after calcination at 650℃. Transmission electron microscopy （TEM） observation indicated that the doped samples have a higher thermal stability. The XRD and Raman spectra confirmed that the Ce0.6Zr0.4-xTbxO2-y cubic solid solution is formed. XPS analysis revealed that Ce and Tb mainly existed in the form of Ce^4＋ and Tb^3 ＋ , and Zr existed in the form of Zr^4＋ on the surface of the samples. The doped samples were homogenous in composition ; the introduction of Tb into the CeO2-ZrO2 promoters resuited in the formation of a solid solution, and the concentration of surface lattice oxygen was increased.展开更多
A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolyt...A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolytes were measured by AUTOLAB PGSTA30 electrochemical measuring device at different temperatures. The conductivities of the electrolytes are 1.62×10^-4 - 6.43×10^-3, 2.52×10^-5 - 3.73×10^-3S·cm^-1 in the temperature range of 350-800℃. The activity energies are 0.54 and 0.84 eV. At the same time BaCe0.9Y0.1O3-α was prepared by direct solid state reaction. The conductivity of BaCe0.9Y0.1O3-α is 1 × 10^-4- 4×10^-3 S·cm^-1 and the activation energy is 0.50 eV at the same condition. The results show that conduction of electrolyte prepared by sol-gel method is higher than the one by solid state reaction. As far as BaCe0.9Y0.1O3-α concerned, its conductivity of the Zr-substituted specimens is decreased.展开更多
A series of solid electrolytes, (Ce 0.8 Ln 0.2 ) 1- x M x O 2-δ (Ln= La, Nd, Sm, Gd, M:Alkali earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite...A series of solid electrolytes, (Ce 0.8 Ln 0.2 ) 1- x M x O 2-δ (Ln= La, Nd, Sm, Gd, M:Alkali earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite phase is formed at 800 ℃. The electrical conductivity and the AC impedance spectra were measured. XPS spectra show that the oxygen vacancies increase owing to the MO doping, which results in the increase of the oxygen ionic transport number and conductivity. The performance of ceria based solid electrolyte is improved. The effects of rare earth and alkali earth ions on the electricity were discussed. The open circuit voltages and maximum power density of planar solid oxide fuel cell using (Ce 0.8 Sm 0.2 ) 1-0.05 Ca 0.05 O 2- δ as electrolyte are 0.86 V and 33 mW·cm -2 , respectively.展开更多
Ce6-xHoxMoO15-δ（0.0≤x≤1.2） was synthesized by modified sol-gel method and characterized by differential X-ray diffraction（XRD）, Raman, and X-ray photoelectron spectroscopy（XPS） methods. The oxide ionic conduc...Ce6-xHoxMoO15-δ（0.0≤x≤1.2） was synthesized by modified sol-gel method and characterized by differential X-ray diffraction（XRD）, Raman, and X-ray photoelectron spectroscopy（XPS） methods. The oxide ionic conductivity of the samples was investigated by AC impedance spectroscopy. It shows that all the samples are single phase with a cubic fluorite structure. The solid solution Ce6-xHoxMoO15-δ（x=0.6） was detected to be the best conducting phase with the highest conductivity（σ1=1.05×10^-2 S/cm） at 800 ℃ and the lowest activation energy（Ea=1.09 eV）. These properties suggest that this kind of material has a potential application in intermediate-low temperature solid oxide fuel ceils.展开更多
The Li_(4+x)Al_xSi_(1-x)O_(4-y)Al_2O_3 (x = 0 to 0.5, y = 0 to 0.5) ionconductors were prepared by the Sol-Gel method and examined in detail. The powder and sinteredsamples were characterized by TG-DTA, XRD, SEM, and ...The Li_(4+x)Al_xSi_(1-x)O_(4-y)Al_2O_3 (x = 0 to 0.5, y = 0 to 0.5) ionconductors were prepared by the Sol-Gel method and examined in detail. The powder and sinteredsamples were characterized by TG-DTA, XRD, SEM, and AC impedance techniques. The experimentalresults show that the conductivity and sinterability increase with the amount of excess Al_2O_3 inthe silicate. The particle size of the powder samples is about 0.13 μm. The maximum conductivity at18 ℃ is 3.057 * 10^(-5) s/cm for Li_(4.4)Al_(0.4)Si_(0.6)O_4-0.3 Al_2O_3.展开更多
基金Project supported by the Natural Science Basic Research Plan in Shaanxi Province of China (2004B13)
文摘The three-way catalysts （TWCs） promoters Ce0.6Zr0.4- x TbxO2-y were prepared by sol-gel method. BET surface areas analysis indicated that an increase of the dopant Tb content from x = 0.05 to x = 0.15 favors an increase of surface area from 66.8 to 80.4 m^2· g^-1 compared with the undoped sample Ce0 .6oZr0.40O2 65.1 m^2·g^- 1 after calcination at 650℃. Transmission electron microscopy （TEM） observation indicated that the doped samples have a higher thermal stability. The XRD and Raman spectra confirmed that the Ce0.6Zr0.4-xTbxO2-y cubic solid solution is formed. XPS analysis revealed that Ce and Tb mainly existed in the form of Ce^4＋ and Tb^3 ＋ , and Zr existed in the form of Zr^4＋ on the surface of the samples. The doped samples were homogenous in composition ; the introduction of Tb into the CeO2-ZrO2 promoters resuited in the formation of a solid solution, and the concentration of surface lattice oxygen was increased.
文摘A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolytes were measured by AUTOLAB PGSTA30 electrochemical measuring device at different temperatures. The conductivities of the electrolytes are 1.62×10^-4 - 6.43×10^-3, 2.52×10^-5 - 3.73×10^-3S·cm^-1 in the temperature range of 350-800℃. The activity energies are 0.54 and 0.84 eV. At the same time BaCe0.9Y0.1O3-α was prepared by direct solid state reaction. The conductivity of BaCe0.9Y0.1O3-α is 1 × 10^-4- 4×10^-3 S·cm^-1 and the activation energy is 0.50 eV at the same condition. The results show that conduction of electrolyte prepared by sol-gel method is higher than the one by solid state reaction. As far as BaCe0.9Y0.1O3-α concerned, its conductivity of the Zr-substituted specimens is decreased.
文摘A series of solid electrolytes, (Ce 0.8 Ln 0.2 ) 1- x M x O 2-δ (Ln= La, Nd, Sm, Gd, M:Alkali earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite phase is formed at 800 ℃. The electrical conductivity and the AC impedance spectra were measured. XPS spectra show that the oxygen vacancies increase owing to the MO doping, which results in the increase of the oxygen ionic transport number and conductivity. The performance of ceria based solid electrolyte is improved. The effects of rare earth and alkali earth ions on the electricity were discussed. The open circuit voltages and maximum power density of planar solid oxide fuel cell using (Ce 0.8 Sm 0.2 ) 1-0.05 Ca 0.05 O 2- δ as electrolyte are 0.86 V and 33 mW·cm -2 , respectively.
基金Supported by the National Natural Science Foundation of China(Nos.20671088, 20871023)Jilin Provincial Science Re-search Foundation, China(No.20070510).
文摘Ce6-xHoxMoO15-δ（0.0≤x≤1.2） was synthesized by modified sol-gel method and characterized by differential X-ray diffraction（XRD）, Raman, and X-ray photoelectron spectroscopy（XPS） methods. The oxide ionic conductivity of the samples was investigated by AC impedance spectroscopy. It shows that all the samples are single phase with a cubic fluorite structure. The solid solution Ce6-xHoxMoO15-δ（x=0.6） was detected to be the best conducting phase with the highest conductivity（σ1=1.05×10^-2 S/cm） at 800 ℃ and the lowest activation energy（Ea=1.09 eV）. These properties suggest that this kind of material has a potential application in intermediate-low temperature solid oxide fuel ceils.
基金theNaturalScienceFoundationofHebeiProvince (No .2 96 16 9)
文摘The Li_(4+x)Al_xSi_(1-x)O_(4-y)Al_2O_3 (x = 0 to 0.5, y = 0 to 0.5) ionconductors were prepared by the Sol-Gel method and examined in detail. The powder and sinteredsamples were characterized by TG-DTA, XRD, SEM, and AC impedance techniques. The experimentalresults show that the conductivity and sinterability increase with the amount of excess Al_2O_3 inthe silicate. The particle size of the powder samples is about 0.13 μm. The maximum conductivity at18 ℃ is 3.057 * 10^(-5) s/cm for Li_(4.4)Al_(0.4)Si_(0.6)O_4-0.3 Al_2O_3.
