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1.
Perumal Elumalai Vladimir V. Plashnitsa Taro Ueda Masaharu Hasei Norio Miura 《Ionics》2006,12(6):331-337
The effect of thickness of oxide-sensing electrode (SE) on NO2 sensitivity of the planar sensor based on yttria-stabilized zirconia (YSZ) was examined at high temperatures. The sensitivity
of the sensor increased with decreasing thickness of SE, and the highest sensitivity was obtained by using the thinnest layer
of Cr2O3–SE (2.7 μm) at 700 °C. In the case of NiO–SE, the highest sensitivity was observed for the sensor using the 4-μm-thick SE
even at a high temperature of 850 °C. Based on the results of the measurements for the complex impedances, the polarization
curves, and the gas-phase NO2 decomposition catalysis, it was confirmed that the catalytic activity to the gas-phase NO2 decomposition on the oxide–SE matrix played an important role in determining the NO2 sensitivity of the present sensors. 相似文献
2.
Perumal Elumalai Vladimir V. Plashnitsa Taro Ueda Masaharu Hasei Norio Miura 《Ionics》2007,13(6):387-393
The effect of thickness of oxide-sensing electrode (SE) on NO2 sensitivity of the planar sensor based on yttria-stabilized zirconia (YSZ) was examined at high temperatures. The sensitivity
of the sensor increased with decreasing thickness of SE, and the highest sensitivity was obtained by using the thinnest layer
of Cr2O3–SE (2.7 μm) at 700 °C. In the case of NiO–SE, the highest sensitivity was observed for the sensor using the 4 μm-thick SE
even at high temperature of 850 °C. Based on the results of the measurements for the complex impedances, the polarization
curves, and the gas-phase NO2 decomposition catalysis, it was confirmed that the catalytic activity to the gas-phase NO2 decomposition on the oxide–SE matrix played an important role in determining the NO2 sensitivity of the present sensors.
This artice was accidentally published twice. This is the second publication, please cite only the authoritative first one
which is available at . An additional erratum is available at .
An erratum to this article can be found at 相似文献
3.
Perovskite-type mixed oxides with the formula LaCr1−yGayO3−δ and La0.95Sr0.02Cr1−yGayO3−δ with y=0.1; 0.2; 0.3 were investigated in view of their usability as electrode materials in exhaust gas sensors for hydrocarbon
(HC) detection. The electrode materials were characterized regarding their catalytic activity for propylene and propane oxidation
and their potentiometric behavior in oxygen containing gaseous mixtures of these combustibles. The potentiometric measurements
with propane indicate higher sensitivities of the strontium doped materials than of the materials without strontium. The comparison
of these results with those of the catalytic investigations using propane show, that a lower catalytic activity comes along
with a higher sensitivity. The electrodes show non-Nernstian behavior.
Paper presented at the 8th EuroConference on Ionics, Carvoeiro, Algarve, Portugal, Sept. 16–22, 2001. 相似文献
4.
Superconductivity is found in tetragonal La3−x
Ba3+x
Cu6O14+δ and La, Ba)6−x
Sr
x
Cu6O14+δ even though they do not possess Cu-O chains or the K2NiF4 structure. Resistivity measurements confirm the occurrence of a transformation from chain-superconductivity to sheet-superconductivity
in YBa2Cu3O7−δ as δ is varied in the range 0.0–0.5.
Contribution No. 481 from the Solid State and Structural Chemistry Unit 相似文献
5.
Vladimir V. Plashnitsa Taro Ueda Perumal Elumalai Toshikazu Kawaguchi Norio Miura 《Ionics》2008,14(1):15-25
The nanostructured thin NiO films with the thicknesses of 30–180 nm were examined as a sensing electrode (SE) for the planar
mixed-potential-type yttria-stabilized zirconia (YSZ)-based NO2 sensor. The sensing characteristics were examined in the temperature range of 600–800 °C under the wet condition (5 vol.%
water vapor). Among the NiO-SEs tested, the 60 nm-thick NiO-SE sintered at 1,000 °C was found to give the highest NO2 sensitivity in the NO2 concentration range of 50–400 ppm accompanying with fast response/recovery at the operating temperatures of 600–700 °C. The
high NO2 sensitivity was attributed to the high catalytic activity for both electrochemical reactions of O2 and NO2 at the interface of NiO-SE/YSZ. The ultrathin gold layer with the thickness of about 60 nm was additionally formed on the
60 nm-thick NiO-SE to fabricate the laminated-type (60 nm NiO/60 nm Au)-SE. It was demonstrated that the use of this laminated
(NiO–Au)-SE improved both the sensitivity and the selectivity to NO2. 相似文献
6.
《Solid State Ionics》2006,177(26-32):2305-2311
The improvement in sensing characteristics of mixed-potential-type NO2 sensor based on an yttria-stabilized zirconia (YSZ) plate was examined by an addition of noble metal to NiO sensing-electrode. Among the various noble metals (Pt, Rh, Ir, Pd and Ru) examined, Rh was found to give a significant enhancement in NO2 sensitivity. In addition, this enhancement was maximum when the Rh content in NiO-SE was 3 wt.%. The sensitivity (emf) to 50 ppm NO2 was as high as about 77 mV for the sensor using the 3 wt.% Rh-loaded NiO-SE at 800 °C under the wet condition (5 vol.% H2O). The NO2 sensitivity was hardly affected by the change of H2O and CO2 concentration in the examined range of 5–15 and 5–20 vol.%, respectively, and was almost stable for about 50 days tested at 800 °C. It was speculated that the improved kinetic effect of Rh loading on the cathodic reaction of NO2 at the interface of SE/YSZ was the major contributing factor for the enhanced NO2 sensitivity of the sensor. 相似文献
7.
I. Ruiz de Larramendi R. López-Antón J. I. Ruiz de Larramendi T. Rojo 《Applied Physics A: Materials Science & Processing》2008,93(3):655-661
Polycrystalline samples of Pr1−x
Sr
x
Fe0.8Co0.2 O3−δ
(x=0.1, 0.2, 0.3) (PSFC) were prepared by the combustion synthesis route at 1200°C. The structure of the polycrystalline powders
was analysed with X-ray powder diffraction data. The X-ray diffraction (XRD) patterns were indexed as the orthoferrite similar
to that of PrFeO3 having a single-phase orthorhombic perovskite structure (Pbnm). Pr1−x
Sr
x
Fe0.8Co0.2O3−δ
(x=0.1, 0.2, 0.3) films have been deposited on yttria-stabilized zirconia (YSZ) single-crystal substrates at 700°C by pulsed
laser deposition (PLD) for application to thin film solid oxide fuel cell cathodes. The structure of the films was analysed
by XRD, scanning electron microscopy (SEM) and atomic force microscopy (AFM). All films are polycrystalline with a marked
texture and present pyramidal grains in the surface with different size distributions. Electrochemical impedance spectroscopy
(EIS) measurements of PSFC/YSZ single crystal/PSFC test cells were conducted. The Pr0.7Sr0.3Fe0.8Co0.2O3−δ
film at 850°C presents a lower area specific resistance (ASR) value, 1.65 Ω cm2, followed by the Pr0.8Sr0.2Fe0.8Co0.2O3−δ
(2.29 Ω cm2 at 850°C) and the Pr0.9Sr0.1Fe0.8Co0.2O3−δ
films (5.45 Ω cm2 at 850°C). 相似文献
8.
Electrochemical sensors using tubular yttria-stabilized zirconia (YSZ) and oxide sensing electrode (SE) were fabricated and
examined for NOx detection at high temperatures. The mixed-potential-type NOx sensor using ZnO-SE gave the highest sensitivity to NOx among other single-type oxides tested as SEs in the temperature range of 600–700 °C. The response of the ZnO-attached device
was a linear for the logarithm of NO2 (NO) concentrations from 40 to 450 ppm. The sensing mechanism of the sensor was discussed on the basis of the gas adsorption-desorption
behavior, the catalytic activity data, and electrochemical behavior for oxides examined. 相似文献
9.
Ma?gorzata A. Ma?ecka Ulrich Burkhardt Dariusz Kaczorowski Marcus P. Schmidt Daniel Goran Leszek K?piński 《Journal of nanoparticle research》2009,11(8):2113-2124
The structure and phase evolution of nanocrystalline Ce1−
x
Ln
x
O2−
x/2−δ (Ln = Yb, Lu, x = 0 − 1) oxides upon heating in H2 was studied for the first time. Up to 950 °C the samples were single-phase, with structure changing smoothly with x from fluorite type (F) to bixbyite type (C). For the Lu-doped samples heated at 1100 °C in the air and H2, phase separation into coexisting F- and C-type structures was observed for ~0.40 < x < ~0.70 and ~0.25 < x < ~0.70, respectively. It was found also that addition of Lu3+ and Yb3+ strongly hinders the crystallite growth of ceria during heat treatment at 800 and 950 °C in both atmospheres. Valency of
Ce and Yb in Ce0.1Lu0.9O1.55−δ and Ce0.95Yb0.05O1.975−δ samples heated at 1100 °C was studied by XANES and magnetic measurements. In the former Ce was dominated by Ce4+, with small contribution of Ce3+ after heating in H2. In the latter, Yb existed exclusively as 3+ in both O2 and H2. 相似文献
10.
Nano-sized Al3+-doped V2O5 cathode materials, Al0.2V2O5.3−δ
, were prepared by an oxalic acid assisted sol–gel method at 350 °C (sample A) and 400 °C (sample B). X-ray diffraction confirmed
that samples A and B were pure phase Al0.2V2O5.3−δ
with an orthorhombic structure close to that of V2O5. Scanning electron microscopy showed that sample A was in nanoscale with a mean particle size about 50 nm. Cyclic voltammetry
showed the good electrochemical and structural reversibility of the Al0.2V2O5.3−δ
nanoparticles during the Li+ insertion/extraction process. The Al0.2V2O5.3−δ
nanoparticles exhibited excellent charge–discharge cycling performance and rate capability compared to that of bulky V2O5 electrodes. For instance, the materials delivered a reversible specific capacity about 180 mAh g−1 (sample A) and 150 mAh g−1 (sample B), in the potential window of 4.0–2.0 V at the current density of 150 mA g−1. The Al0.2V2O5.3−δ
nanoparticles in particular showed almost no capacity fading for at least 50 cycles. 相似文献
11.
M. Ganesan 《Ionics》2008,14(5):395-401
Chromium-substituted Li4Ti5O12 has been investigated as a negative electrode for future lithium batteries. It has been synthesized by a solid-state method
followed by quenching leading to a micron-sized material. The minimum formation temperature of Li4Ti2.5Cr2.5O12 was found to be around 600 °C using thermogravimetric and differential thermal analysis. X-ray diffraction, scanning electron
microscopy, cyclic voltammetry (CV), impedance spectroscopy, and charge–discharge cycling were used to evaluate the synthesized
Li4Ti2.5Cr2.5O12. The particle size of the powder was around 2–4 μm. CV studies reveal a shift in the deintercalation potential by about 40
mV, i.e., from 1.54 V for Li4Ti5O12 to 1.5 V for Li4Ti2.5Cr2.5O12. High-rate cyclability was exhibited by Li4Ti2.5Cr2.5O12 (up to 5 C) compared to the parent compound. The conduction mechanism of the compound was examined in terms of the dielectric
constant and dissipation factor. The relaxation time has been evaluated and was found to be 0.07 ms. The mobility was found
to be 5.133 × 10−6 cm2 V−1 s−1. 相似文献
12.
A mixed potential type yttria-stabilized zirconia-based sensor using NiO sensing electrode and Pt reference electrode was fabricated, and its NO2 sensing characteristics were examined at various operating temperatures in the range of 700–950 °C. It was observed that the sensitivity to NO2 strongly depends on the operating temperature of the sensor; the sensitivity decreases with increasing operating temperature, while the response/recovery rates increase. To rationalize this temperature dependence of NO2 response, polarization curves and complex impedances of the sensor were measured in the base gas and in the sample gas (400 ppm NO2?+?base gas) at various operating temperatures. It turned out that the operating temperature had a strong influence on the rate of anodic reaction of oxygen; the increased rate of anodic reaction leads to lower NO2 sensitivity and quicker response/recovery at higher operating temperature. 相似文献
13.
BaCe0.7Ta0.1Y0.2O3−
δ
(BCTY) and BaCe0.8Y0.2O3−
δ
(BCY) were synthesized by solid-state reaction method at 1,300 °C for 20 h. After being exposed in 3% CO2 + 3% H2O + 94% N2 at 700 °C for 20 h, the BCTY exhibited adequate chemical stability against carbonations while BCY decomposed into BaCO3 and CeO2. The BCTY showed the similar thermal expansion behavior to BCY from room temperature to 1,000 °C in air. The BCTY displayed
a conductivity of 0.007 S/cm at 700 °C in humid hydrogen, lower than that of BCY (0.009 S/cm). A fuel cell with 10-μm thick
BCTY membrane prepared through an all-solid-state process exhibited 1.004 V for OCV, 330 mW/cm2 for maximum output at 700 °C, respectively. Short-term test shows that the fuel cell performance does not degrade after 20 h. 相似文献
14.
Fine and uniform La0.6Sr0.4Co0.2Fe0.8O3−δ
powder was synthesized by a glycine–nitrate combustion process. La0.6Sr0.4Co0.2Fe0.8O3−δ
electrodes were prepared on dense Ce0.8Sm0.2O2−δ
electrolyte substrates using a spin-coating technique by sintering at 900–1,000 °C. The electrode properties of La0.6Sr0.4Co0.2Fe0.8O3−δ
were investigated by electrochemical impedance spectroscopy and chronopotentiometry techniques with respect to preparation
conditions and the resulting microstructures. The results indicate a significant effect of the microstructure on the electrode
processes and polarization characteristics. The oxygen adsorption and dissociation process acted as a larger contribution
to the overall electrode polarization R
p in magnitude compared with the charge transfer process due to relatively low porosity levels of the electrodes. It was detected
that the grain size of the electrodes exhibited a crucial role on the electrocatalytic reactivity. At 800 °C, the electrode
sintered at 950 °C attained a polarization resistance of 0.18 Ω cm2, an overpotential of 27 mV at a current density of 200 mA cm−2, and an exchange current density of 308 mA cm−2. 相似文献
15.
Sonochemical synthesis, size controlling and gas sensing properties of NiO nanoparticles 总被引:1,自引:0,他引:1
Nanoparticles of NiO (NP-NiO) were prepared by a novel sonochemical route from Ni acetate and sodium hydroxide without any requirement of calcinations steps at high temperature and without surfactants. Drop casting of the nanocrystals onto alumina substrates allowed the fabrication of gas sensing devices, which were tested towards NO2 and CO and showed promising results. At low working temperature, the NiO nanoparticles based sensors are selective to nitrogen oxide; in fact a good sensitivity is shown at 200 °C at low concentration (2 ppm), while at temperature above 350 °C, high responses are obtained for carbon monoxide. The results obtained are stimulating for further developing of NP-NiO based sensor devices. 相似文献
16.
Fan Yu-shan Song Hong-zhang Li Zhi-hui Yang De-lin Hu Xing 《Frontiers of Physics in China》2006,1(3):368-370
The oxygen adsorption-desorption properties of RBa2Cu3O7−δ
(R = Gd, Er, Eu, Dy, Sm, Ho and Nd) and Y1−x
LaxBa2Cu3O7−δ
(x=0.1, 0.5 and 1.0) were investigated from room temperature to 950 °C by thermogravimetry (TG). The results show that all samples
will release oxygen with the increasing of temperature and the released oxygen can be absorbed back into the sample when temperature
decreases. However, dependent on the rare earth element, the amount of the released oxygen is different for these samples.
Moreover, in the temperature increasing and decreasing circle the repetition of oxygen adsorption-desorption is also different. 相似文献
17.
A. E. Abdel Ghany A. M. A. Hashem H. A. M. Abuzeid A. E. Eid H. A. Bayoumi C. M. Julien 《Ionics》2009,15(1):49-59
Single phase LiCo1 − y
Ni
y
O2 (y = 0.4 and 0.5) with fine particles and high homogeneity was synthesized by “chimie douce” assisted by citric acid as the
polymeric agent and investigated as positive electrodes in rechargeable lithium batteries. The long-range and short-range
structural properties are investigated with experiments including X-ray diffraction (XRD), Fourier transform infrared spectroscopy
(FTIR), and superconducting quantum interference device magnetometry. The physicochemical properties of the powders (crystallinity,
lattice constants, grain size) have been investigated in this composition. The powders adopted the α-NaFeO2 structure as it appeared from XRD and FTIR results. Magnetic measurements shows signal at low temperature attributed to the
magnetic domains in the nanostructure sample from which we estimated that the cation mixing are 3.35 and 4.74% for y = 0.4 and 0.5 in LiCo1 − y
Ni
y
O2, respectively. LiCo0.5Ni0.5O2 cathode yields capacity (135 mAh g−1) compared to LiCo0.6Ni0.4O2 cathode (147 mAh g−1) when discharged to a cutoff voltage of 2.9 V vs. Li/Li+. Lower capacity loss and higher discharge efficiency percentage are observed for the cell of LiCo0.6Ni0.4O2 cathode. 相似文献
18.
We have studied the growth characteristics, structure, and parameters of the epitaxial heterostructures (001)NdBa2Cu3O7−δ
/(100)SrTiO3/(001)NdBa2Cu3O7−δ
grown by laser ablation on a (100)LaAlO3 substrate with a thin (∼2 nm) YBa2Cu3O7−δ
intermediate layer. The use of an YBa2Cu3O7−δ
intermediate layer promotes layered growth of the (200 nm) NdBa2Cu3O7−δ
layer, whose free-surface roughness is 4–5 nm. The resistance of the NdBa2Cu3O7−δ
layers began to fall off abruptly at T=92 K, and at T≈87 K it vanished completely. The critical current density in the NdBa2Cu3O7−δ
layers at T=76 K exceeded 106 cm2 A/cm2. The dielectric constant of the (400 nm) SrTiO3 layer sandwiched between the NdBa2Cu3O7−δ
epitaxial layers grew by roughly threefold as the temperature was lowered in the interval 300–4.2 K. When a bias voltage
of ±2.5V was applied to the NdBa2Cu3O7−δ
electrodes, the relative dielectric constant of the (400 nm) SrTiO3 intermediate layer fell from 1150 to 400 (T=32 K, f=100 kHz). The conductivity of the SrTiO3 intermediate layer in the direction perpendicular to the substrate plane increased with temperature and the electric field
strength.
Fiz. Tverd. Tela (St. Petersburg) 41, 395–403 (March 1999) 相似文献
19.
V. N. Gridnev B. B. Krichevtsov V. V. Pavlov R. V. Pisarev A. A. Rzhevskii 《Physics of the Solid State》1998,40(5):872-873
An experimental study of nonreciprocal spatial-dispersion effects in para-(Cd1−x
MnxTe), ferro-(LiFe5O8), and antiferromagnetic (Cr2O3) crystals caused by an external magnetic field or magnetic order is reported.
Fiz. Tverd. Tela (St. Petersburg) 40, 946–948 (May 1998) 相似文献
20.
N. Sankara Subramanian R. Vivek Sabaapathy P. Vickraman G. Vimal Kumar R. Sriram B. Santhi 《Ionics》2007,13(5):323-328
P-type porous silicon (PS) structure has been prepared by anodic electrochemical etching process under optimized conditions.
Photoluminescence studies of the PS structure show emission at longer wavelengths (red) for the excitation at 365 nm. Scanning
electron microscope investigations of the PS surface confirm the formation of uniform porous structure, and the pore diameter
have been estimated as 25 μm. Pd:SnO2/PS/p-Si heterojunction with top gold ohmic contact developed by conventional methods has been used as the sensor device.
Sensing properties of the device towards liquefied petroleum gas (LPG) and NO2 gas have been investigated in an indigenously developed sensor test rig. The response and recovery characteristics of the
sensor device at different operating temperatures show short response time for LPG. From the studies, maximum sensitivity
and optimum operating temperature of the device towards LPG and NO2 gas sensing has been estimated as 69% at 180 °C and 52% at 220 °C, respectively. The developed sensor device shows a short
response time of 25 and 57 s for sensing LPG and NO2 gases, respectively.
Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7–9, 2006. 相似文献