共查询到20条相似文献,搜索用时 15 毫秒
1.
N. Parkansky L. Glikman I. I. Beilis B. Alterkop R. L. Boxman D. Gindin 《Plasma Chemistry and Plasma Processing》2007,27(6):789-797
Electrode erosion was studied in pulsed arcs ignited between two electrodes comprised of 99.99% C (graphite) and 99.5% W submerged
in deionized water or analytical (99.8%) ethanol. In the both cases the erosion rate increased proportionally to the pulse
energy, and the total electrode erosion per unit energy was inversely proportional to the discharge pulse duration. Fifteen
and sixty-μF discharge capacitors were used for formation of the pulses in water. It was obtained that, respectively (a) erosion
of the tungsten anode (Wa) was by factors of 5–6 and ∼10 greater than that of the carbon (Cc) cathode; (b) erosion of the carbon anode (Ca) was by a factor of 1.34 greater and by a factor of 2.65 less than that of the tungsten cathode (Wc); (c) the total erosion rate of both electrodes (anode and cathode) per unit pulse energy for the Wa–Cc pair was greater by factors of 11 and 12.5 than that for the Wc–Ca pair. 相似文献
2.
Jawad Haidar 《Plasma Chemistry and Plasma Processing》2009,29(4):307-319
Nanopowders of metals and metal oxides have been produced using an arc operated between a refractory rod anode and a hollow
cathode (J. Haidar in A method and apparatus for production of material vapour, Australian Patent No. 756273, 1999). the arc
attachment to the anode is through a small region of molten metal located at the tip of the rod anode. Heat from the arc evaporates
the molten metal and the vapour is passed through the arc plasma before condensing into sub-micron particles downstream of
the cathode. A precursor metal is continuously fed onto the tip of the anode to maintain the molten metal region and compensate
for losses of materials due to evaporation. The particle size of the produced powder depends on the pressure in the arc chamber
and for production of nanoparticles in the range below 100 nm we use a pressure of 100 torr. Aluminium has been used as a
precursor material, leading to production of aluminium metal nanopowders when the arc is operated in argon and to aluminium
oxide nanopowders for operation in air. For operation in air, the products are made of γ-Al2O3. 相似文献
3.
Ozone (O3) has been generated on Ni–Sb–SnO2/Ti electrode as anode immersed in acidic media at 25 °C by electrochemical process. The anode was electrochemically characterized
by cyclic voltammetry and morphologically characterized by scanning electron microscopy (SEM) and X-ray diffraction. The concentration
of dissolved ozone was determined by a UV/Vis spectrophotometer. The type of electrode with different times coating on the
titanium mesh and different acid type and various concentrations (C
acid) were used, and the stability of the electrode was investigated under the experimental conditions by SEM images. Results
shows that higher efficiency (53.7%) for O3 generation by electrochemical oxidation of water were obtained in HClO4 (1 M) and an applied potential of 2.4 V vs. Ag/AgCl in 150 ml volume undivided electrochemical cell. 相似文献
4.
Jaekyung Yoon Sanghyun Bae Jinwook Ha Hyunku Joo 《Research on Chemical Intermediates》2009,35(3):287-297
In this study, an anodized tubular TiO2 electrode (ATTE) on titanium foil was prepared and used both as a photoanode and a cathode in an enzymatic photoelectrochemical
system to split water into oxygen and hydrogen. The effect of applied voltage when anodized, thickness of the foil, electrolytes,
annealing temperature, and cathodes was investigated (optimum conditions: 20 V of applied voltage in 0.5 vol.% of hydrofluoric
acid, 0.25-mm foil thickness, and 450–650°C annealing temperature). The samples with higher activities had similar X-ray diffraction
(XRD) patterns, clearly indicating that the samples showing the highest evolution rate were composed of both anatase and rutile,
while those showing a lower evolution rate were made of either anatase or rutile. The ATTE successfully replaced the Pt mesh
cathode and the immobilization of the enzyme enhanced the H2 evolution by 50% (from ca. 66 to 99 μmol/(h × cm2)). Moreover, the use of KOH instead of Tris–HCl buffer in a cathodic compartment further increased the H2 evolution to 115 μmol/(h × cm2). 相似文献
5.
Zenta Kato Koichi Izumiya Naokazu Kumagai Koji Hashimoto 《Journal of Solid State Electrochemistry》2009,13(2):219-224
The change in the polarization potentials of anode and cathode due to pH change on electrode surfaces during galvanostatic
polarization was examined in 0.5 M NaCl solutions of different pH. On the basis of these results, feeding of the anolyte after
oxygen evolution to the cathode compartment for hydrogen production was examined for energy-saving seawater electrolysis.
This was assumed to prevent the occurrence of a large pH difference on cathode and anode in electrolysis of neutral solution
if sufficient H+ is permeated through the membrane. The cell performance was examined using Nafion 115 or Selemion HSF membranes for separation
of anode and cathode compartments. The permeation fraction of H+ with Nafion 115 was 45–65% in 0.5 M NaCl and was about 90% in 0.25 M Na2SO4. These values were smaller than 97% necessary for prevention of the occurrence of pH difference on cathode and anode. The
permeation fraction of H+ with Selemion HSF became more than 97% during electrolysis of 0.025 M Na2SO4, and the cell voltage was kept at low values. These results indicate the effectiveness of our seawater feeding system if
the 97% H+ permeation fraction through the membrane is attained.
Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on Electrochemical/Chemical
Reactivity of Metastable, Warsaw, 17th-21st September, 2007. 相似文献
6.
Tian Yongmei Huang Jichun Gao Yuan Cao Dianxue Wang Guiling 《Journal of Solid State Electrochemistry》2012,16(5):1901-1906
Fe–N–C catalysts were prepared through metal-assisted polymerization method. Effects of carbon treatment, Fe loading, nitrogen
source, and calcination temperature on the catalytic performance of the Fe–N–C for H2O2 electroreduction were measured by voltammetry and chronoamperometry. The Fe–N–C catalyst shows optimal performance when prepared
with pretreated active carbon, 0.2 wt.% Fe, paranitroaniline (4-NA) and one-time calcination. The Fe–N–C catalyst displayed
good performance and stability for electroreduction of H2O2 in alkaline solution. An Al–H2O2 semi-fuel cell was set up with Fe–N–C catalyst as cathode and Al as anode. The cell exhibits an open-circuit voltage of 1.3 V
and its power density reached 51.4 mW cm−2 at 65 mA cm−2. 相似文献
7.
Takayuki Watanabe Narengerile Hiroshi Nishioka 《Plasma Chemistry and Plasma Processing》2012,32(1):123-140
Decomposition of acetone, methanol, ethanol, and glycerine by water plasmas at atmospheric pressure has been investigated
using a direct current discharge. At torch powers of 910–1,050 W and organic compound concentrations of 1–10 mol%, the decomposition
rate of methanol and glycerine was over 99%, while those of acetone and ethanol was 95.4–99%. The concentrations of H2 obtained were 60–80% in the effluent gas for any compounds by pyrolysis. Based on the experimental results, the decomposition
mechanism of organic compounds in water plasmas was proposed and the roles of intermediate species such as CH, CH3, and OH have been investigated; CH radical generated from organic compounds decomposition was easily oxidized to form CO;
incomplete oxidation of CH3 leads to C2H2 generation as well as soot formation; and negligible amount of soot observed from glycerine decomposition even at high concentration
indicated that oxidation of CH×(×:1–3) was enhanced by OH radical. 相似文献
8.
A direct ethanol fuel cell (DEFC) is developed with low catalyst loading at anode and cathode compared to that reported in the literature. Pt/Ru (40%:20% by wt.)/C and Pt-black were used as anode and cathode catalyst with loadings in the range of 0.5–1.2 mg/cm2. The temperatures of anode and cathode were varied from 34 °C to 110 °C, and the pressure was maintained at 1 bar. Although low catalyst loading was used, the cell performance is enhanced by 40–50% with the use of low concentration of sulfuric acid in ethanol and Ni-mesh as current collector at the anode. The power density 15 mW/cm2 at 32 mA/cm2 of current density is obtained from the single cell with 0.5 mg/cm2 loading of Pt–Ru/C at anode (90 °C) and Pt-black at cathode (110 °C). The performance of DEFC increases with the increase in ethanol and sulfuric acid concentrations, electrocatalyst loadings up to 1 mg cm−2 at anode and cathode. However, the performance of DEFC decreases with further increase in electrocatalyst loading. 相似文献
9.
The miniaturized atmospheric pressure glow discharge (APGD) generated between a solid electrode and a flowing small size liquid
cathode (dimension 2 mm) was investigated here using optical emission spectroscopy. The discharge was studied in an open air
atmosphere, and the spectral characteristics of the plasma source was examined. Analysed APGD was operated at a discharge
voltage of 1,100–1,700 V, a discharge current of 20 mA and gaps between a solid anode and a liquid cathode in the range from
0.5 to 3.5 mm. The emission intensities of the main species were measured as a function of various experimental conditions,
including the solution flow rate, the gap between the electrodes, and the concentration of hydrochloric acid. The excitation
temperature, the vibrational temperatures calculated from N2, OH, and NO bands, and the rotational temperatures determined from band of OH, N2 and NO, were found to be dependent on these experimental parameters. The electron number density was determined from the
Stark broadening of Hβ line. Additionally, the ionization temperature and degree were calculated using the Saha–Boltzmann equation, with the ion
to atom ratio for magnesium (MgII/MgI). The results demonstrated that T
exc(H), T
vib(N2), T
vib(OH), T
vib(NO) and T
rot(OH) were well comparable (~3,800–4,200 K) for selected plasma generation conditions (gap ≥2.5 mm, HCl concentration ≥0.1 mol L−1), while the rotational temperatures determined from band of N2 (~1,700–2,100 K) and band of NO (~3,000 K) were considerably lower. The electron number density was evaluated to be (3.4–6.8) × 1020 m−3 and the ionization temperature varied, throughout in the 4,900–5,200 K range. 相似文献
10.
Qiang Li Liping Sun Lihua Huo Hui Zhao Jean-Claude Grenier 《Journal of Solid State Electrochemistry》2012,16(3):1169-1174
The performance of Ca2Fe1.4Co0.6O5–Ce0.9Gd0.1O1.95 (CFC–CGO) composite cathode has been investigated for potential application in intermediate-temperature solid oxide fuel
cells (IT-SOFCs). The composite cathodes are prepared and characterized by XRD and SEM, respectively. The electrochemical
properties of the composite cathodes are investigated using AC impedance and DC polarization methods from 500 to 700 °C under
different oxygen partial pressures. The polarization resistance (R
p) decreases with the increase of CGO content in the composite electrode. The addition of 40 wt.% CGO in CFC results in the
lowest R
p of 0.48 Ω cm2 at 700 °C in air. Oxygen partial pressure dependence study indicates that the charge-transfer process is the rate limiting
step for oxygen reduction reaction. CFC-40CGO composite cathode exhibits the lowest overpotential of about 67 mV at a current
density of 85 mA cm−2 at 700 °C in air. 相似文献
11.
Ekaterina V. Tsipis Vladislav V. Kharton 《Journal of Solid State Electrochemistry》2008,12(11):1367-1391
Following previous surveys of the solid electrolyte ceramics and electrode reaction mechanisms in solid oxide fuel cells,
this review is focused on the comparative analysis of electrochemical performance, thermal expansion, oxygen ionic and electronic
transport, and durability-determining factors in the major groups of electrode materials. The properties of mixed-conducting
oxide phases with perovskite-related and fluorite structures, ceramic–metal and oxide composites, and catalytically active
additives are briefly discussed, with emphasis on the approaches and findings reported during the last 10–15 years. The performance
of conventional and alternative electrode materials in the cells with ZrO2-, CeO2-, LaGaO3-, and La10Si6O27-based electrolytes is appraised in the context of potential optimization strategies. Particular attention is centered on
the cathode and anode compositions providing maximum electrochemical activity and stability and on the critical aspects relevant
for electrode microstructure engineering. 相似文献
12.
Qiang Gong Yu-Shi He Yang Yang Xiao-Zhen Liao Zi-Feng Ma 《Journal of Solid State Electrochemistry》2012,16(4):1383-1388
A LiFePO4/C-polypyrrole (LiFePO4/C-PPy) composite as a high-performance cathode material is successfully prepared through a simple chemical vapor deposition
(CVD) method. According to the transmission electron microscope (TEM) analysis, the surface of the LiFePO4/C is surrounded with PPy in the LiFePO4/C-PPy composite. The as-prepared LiFePO4/C-PPy material shows outstanding rate capability at 20°C and good cycle performance at 55°C in comparison with those of the
bare LiFePO4/C material against Li anode. After 700 cycles, the discharge capacity of LiFePO4/C-PPy could still remain 110 mA h g−1 with the retention of 82% at 5 C rate at 55°C. This could be ascribed to the fact that PPy coating on LiFePO4/C could significantly improve the ionic conductivity of the LiFePO4/C-PPy composite and could greatly reduce the electrode resistance. Furthermore, the PPy coating on LiFePO4/C could effectively decrease the dissolution of Fe in the LiPF6 electrolyte and subsequently suppress the reduction of Fe ions on anode. 相似文献
13.
R. Z. Liu S. R. Wang Bo Huang C. H. Zhao J. L. Li Z. R. Wang Z. Y. Wen T. L. Wen 《Journal of Solid State Electrochemistry》2009,13(12):1905-1911
A dip-coating method to fabricate anode-supported tubular solid oxide fuel cells has been successfully developed. The length,
outside diameter, and thickness of the single cell are 10.8 cm, 1.0 cm, and 0.6 mm, respectively. The area of the cathode
is 15–16 cm2 (cathode length = 4.8 cm). The cell consists of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte
film, a LSM-ScSZ cathode functional layer, and a LSM cathode current collecting layer. A preliminary examination of the single
tubular cell has been carried out and an acceptable performance was obtained. The maximum power density was, respectively,
325, 276, 208, and 168 mW cm−2 at 850, 800, 750, and 700 °C, when operating with humidified hydrogen. 相似文献
14.
Wu Yan Jia Qingzhu Wang Bingwen Zheng Wei Yi Shouzhi 《Russian Chemical Bulletin》2010,59(9):1686-1691
The influence of a thin spreading solvent film (ethanol, diethyl ether, and three fractions of petroleum ether boiling at
30–60 °C, 60–90 °C, and 90–120 °C) on the properties of hexadecan-1-ol (C16H33OH) monolayers at the air—water interface was studied. The specific evaporation resistance and the surface pressure were determined
to describe the spreading behavior of the C16H33OH monolayers. The physical properties of the solvents and the images obtained in an atomic force microscope were examined.
The time of establishing the equilibrium spreading surface pressure of monolayers can be reduced using a more volatile solvent
with a lower boiling point and a lower relative density. The influence of the monolayer nature on water evaporation corresponds
to the order of changing the solvent spreading rate: petroleum ether (30–60 °C) > diethyl ether > ethanol > petroleum ether
(60–90 °C) > petroleum ether (90–120 °C). The monolayers formed upon petroleum ether (30–60 °C) spreading form a film with
a less deficient and relatively planar surface. When ethanol is used as a spreading solvent, water evaporation is accelerated
rather than retarded, while petroleum ether (30–60 °C) is more appropriate for this purpose. 相似文献
15.
A. J. Appleby 《Journal of Solid State Electrochemistry》2009,13(7):991-997
A critical discussion of dioxygen reduction kinetics using the Tafel (for the irreversible cathode process) and the Butler–Volmer
(anode process) rate equations has been used to evaluate the accuracy of “standard” modeling interpretations of experimental
cell potential current (E–I) plots. The potential–current curve for what is believed to be an optimized Nafion™-bonded fuel cell cathode was analyzed.
It appears to behave as a well-ordered diffusional system and shows high electrocatalyst utilization based on its electrocatalytic
and gas diffusion characteristics. The electrode appears to perform as expected, without any anomalous characteristics showing
any lower than expected electrocatalyst utilization. Any improvement in electrode performance, which is certainly desirable,
seems to demand an improved diffusional structure, barring any potential (although unlikely) change in electrochemical kinetic
characteristics.
相似文献
A. J. ApplebyEmail: |
16.
We report the electrochemical reduction of CO2 into hydrocarbons using a new electrochemical membrane reactor holding a yet unreported membrane electrode assembly comprising a copper mesh cathode and a Ti felt coated with mixed metal oxide (MMO) catalyst anode separated by a proton conductive membrane. CO2(g) was supplied to the cathodic reduction compartment, whilst humidified N2 was supplied to the anodic oxidation compartment. The MMO anode produces protons transported across the proton exchange membrane and electrons transported via the external circuit to the copper cathode to reduce CO2(g). Production rates of methane, propane, propene, iso-butane and n-butane were determined as a function of cell potential at temperatures between 30 and 70 °C and relative humidity between ca. 25% and 75%. Maximum methane concentration and the current efficiency for production of hydrocarbons were 3.29 ppm and 0.12%, respectively. Whilst the observed product spectrum is desirable, such low current efficiencies require systematic optimization of the catalytic membrane system, in particular an improved cathode with an optimum contact between proton conducting membrane, electrode and catalyst is desired. 相似文献
17.
Lei Zhang Rong Lan Arno Kraft Mingtai Wang Shanwen Tao 《Electrochemistry communications》2010,12(11):1589-1592
A cost-effective cell fabrication process was developed for intermediate temperature solid oxide fuel cells (IT-SOFCs). Co-doped ceria Ce0.8Gd0.05Y0.15O1.9 (GYDC) was synthesized by carbonate co-precipitation method. Lithiated NiO was prepared by glycine-nitrate combustion method and adopted as cathode material for IT-SOFCs. Single cell was fabricated by one-step dry-pressing and co-firing anode, anode functional layer (AFL), electrolyte and cathode together at 1200 °C for 4 h. The cell presented decent performance and an overall electrode polarization resistance of 0.54 Ω cm2 has been achieved at 600 °C. These results demonstrate the possibility of using lithiated NiO as cathode material for ceria-based IT-SOFCs and the development of affordable fuel cell devices is encouraged. 相似文献
18.
Y. J. Leng S. H. Chan K. A. Khor S. P. Jiang 《Journal of Solid State Electrochemistry》2006,10(6):339-347
Development of high performance cathodes with low polarization resistance is critical to the success of solid oxide fuel cell
(SOFC) development and commercialization. In this paper, (La0.8Sr0.2)0.9MnO3 (LSM)–Gd0.2Ce0.8O1.9(GDC) composite powder (LSM ~70 wt%, GDC ~30 wt%) was prepared through modification of LSM powder by Gd0.2Ce0.8(NO3)
x
solution impregnation, followed by calcination. The electrode polarization resistance of the LSM–GDC cathode prepared from
the composite powder was ~0.60 Ω cm2 at 750 °C, which is ~13 times lower than that of pure LSM cathode (~8.19 Ω cm2 at 750 °C) on YSZ electrolyte substrates. The electrode polarization resistance of the LSM–GDC composite cathode at 700 °C
under 500 mA/cm2 was ~0.42 Ω cm2, which is close to that of pure LSM cathode at 850 °C. Gd0.2Ce0.8(NO3)
x
solution impregnation modification not only inhibits the growth of LSM grains during sintering but also increases the triple-phase-boundary
(TPB) area through introducing ionic conducting phase (Gd,Ce)O2-δ, leading to the significant reduction of electrode polarization resistance of LSM cathode. 相似文献
19.
Takaaki Sakai Hao Zhong Hiroyuki Eto Tatsumi Ishihara 《Journal of Solid State Electrochemistry》2010,14(10):1777-1780
A composite anode of NiFe–MgO (2.5 wt.%)–La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) (10 wt.%) for solid oxide fuel cells using directly CH4 as fuel was studied. Compared with previously reported NiFe–LSGM (10 wt.%) cermet anode, the NiFe–MgO–LSGM anode exhibited
superior power generation performance, stability under CH4 atmosphere at 973 K, and high tolerance against the carbon deposition. These improvements by the additives are explained
by the increase in basic property of anode material. The anode activity of NiFe–MgO–LSGM cermet for CH4 fuel is still lower than that for H2 one. However, comparing with that of NiFe–LSGM cermet, anodic overpotential slightly decreased by the addition of MgO, suggesting
the improved surface activity. 相似文献
20.
The electrochemical behaviour of lanthanum fluoride dissolved in molten lithium fluoride and in eutectic mixture LiF-CaF2 was investigated by cyclic voltammetry and laboratory electrolysis. The cyclic voltammetry experiments were carried out at
900°C and 800°C, respectively, in a graphite crucible (counter electrode). Several types of working electrodes (Mo, W, Ni
and Cu) were used. Ni/Ni(II) was used as a reference electrode. Laboratory electrolysis was carried out in the system LiF-CaF2-LaF3 at 800°C in galvanostatic (j
c = −0.21 A cm−2) and potentiostatic (E = 0.87 V) regimes. In both cases, nickel served as the cathode and graphite as the anode. It was found that no new separate
reduction peak occurred on the molybdenum or tungsten electrodes in the investigated systems. When copper or nickel electrodes
were used, new peaks corresponding to the reduction of lanthanum(III) to lanthanum metal appeared. This can be explained by
the formation of alloys or intermetallic compounds of lanthanum with copper or nickel. X-ray microanalysis showed that lanthanum
was electrodeposited together with calcium under formation of intermetallic compounds with the electrode materials in the
galvanostatic regime. In the potentiostatic regime, mainly lanthanum was deposited, which enabled its separation. 相似文献