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1.
We report here the enhanced sensing characteristics to H2 for a potentiometric sensor using an yttria-stabilized zirconia (YSZ) solid electrolyte and a ZnO(+ 84 wt.% Ta2O5) sensing electrode (SE) after aging at 500 °C. The emf response toward 400 ppm H2 was found to gradually increase up to − 800 mV after 40 days operation (aging) and was stabilized at this value until the 90th day. The aged and stabilized sensor exhibited highly sensitive response to H2, with minor responses toward other examined gases such as NOx and HCs. The 90% response time toward 100 ppm H2 was approximately 70 s. The H2 sensitivity of the stabilized sensor was hardly affected by changes in water vapor as well as O2 concentration, with repeatable and reproducible responses to H2.  相似文献   

2.
Redox stable K2NiF4 type layered perovskite SrLaFeO4  δ(SLFO4  δ) has been prepared and evaluated as anode for solid oxide fuel cell (SOFC). The SLFO4  δ shows linear thermal expansion behavior with TEC of 14.3 × 10 6 K 1. It also demonstrates excellent catalytic activity for various fuels. A scandia stabilized zirconia (ScSZ, 180 μm) electrolyte supported SOFC with the anode achieves maximum power densities (Pmax) of 0.93, 0.76, 0.63, and 0.46 Wcm 2 at 900–750 °C, respectively, in wet H2. Pmaxs of cells supported by 250 μm ScSZ reach 0.57, 0.60 and 0.50 Wcm 2 in H2, H2 + 50 ppm H2S and propane, respectively, at 800 °C. Moreover, the cells show stable power output during ~ 100 h operation at 800 °C under 0.7 V in various fuels. The Pmax at 800 °C in wet H2 even increases by ~ 11% in the subsequent two thermal cyclings, indicating that SLFO4  δ is a promising anode candidate for SOFC with good electro-catalytic activity, high stability and resistance to sulfur and coking.  相似文献   

3.
A new type of lithium ion conducting solid electrolyte based on a cubic rare earth oxide was developed by co-doping LiNO3 and KNO3 into a (Gd1−xNdx)2O3 solid, which possesses large interstitial open spaces within the structure. Among the samples prepared, 0.6(Gd0.4Nd0.6)2O3–0.16LiNO3–0.24KNO3 exhibits the highest lithium ion conductivity of 8.05 × 10−2 and 1.35 × 10−3 S cm−1 at 400 and 100 °C, respectively, which is comparable to that of the LISICON materials. Pure Li+ ion conduction was successfully demonstrated by the dc electrolysis method.  相似文献   

4.
A novel three-dimensional (3D) electrochemical sensor was developed for highly sensitive detection of hydrogen peroxide (H2O2). Monolithic and macroporous graphene foam grown by chemical vapor deposition (CVD) served as the electrode scaffold. Using in-situ polymerized polydopamine as the linker, the 3D electrode was functionalized with thionine molecules which can efficiently mediate the reduction of H2O2 at close proximity to the electrode surface. Such stable non-enzymatic sensor is able to detect H2O2 with a wide linear range (0.4 to 660 μM), high sensitivity (169.7 μA mM 1), low detection limit (80 nM), and fast response (reaching 95% of the steady current within 3 s). Furthermore, this sensor was used for real-time detection of dynamic release of H2O2 from live cancer cells in response to a pro-inflammatory stimulant.  相似文献   

5.
A mixed ionic and electronic conductor, BaPr0.8In0.2O3  δ (BPI), was synthesized and examined as a cathode material for proton-conducting solid oxide fuel cells (H-SOFCs). X-ray diffraction analysis revealed that BPI had a perovskite structure and showed satisfactory tolerance to CO2 and H2O and good chemical compatibility with BaZr0.1Ce0.7Y0.1 Yb0.1O3  δ (BZCYYb) electrolyte. Test cells with a single-phase BPI cathode exhibited excellent electrochemical performances, demonstrating a peak power density of ~ 688 mW cm 2 at 750 °C. Furthermore, the cells with a BPI cathode showed very stable power output at a cell voltage of 0.7 V at 600 °C over 100 h, suggesting that BPI is a promising alternative cathode for H-SOFCs.  相似文献   

6.
The charge accumulation due to peroxidase (POD)-catalyzed reduction of H2O2 in a test solution (4 μL) by Os(II) in a POD/PVI[Os(dmebpy)2Cl]-immobilized layer on an electrode (PVI = poly(1-vinylimidazole), dmebpy = 4,4′-dimethyl-2,2′-bipyridine) was monitored potentiometrically for the detection of H2O2. Before potentiometry, the Os(II)/Os(III) ratio of the modified electrode was controlled by pre-electrolysis at a given potential in a separated electrolysis cell. The redox potential of the Os polymer film in the test solution shifted to the positive side on the addition of H2O2 and reached a constant value due to the accumulation of Os(III) in the film. The total amount of the accumulated charge was determined from the area of the portion corresponding to the redox potential shift on a reversible cyclic voltammogram recorded separately. The low detection limit (5 pmol H2O2) was realized with 82–90% of the recovery percentage.  相似文献   

7.
A cathode-supported electrolyte film was fabricated by tape casting and co-sintering techniques. (La0.8Sr0.2)0.95MnO3 (LSM95), LSM95/Zr0.89Sc0.1Ce0.01O2?x (SSZ), and SSZ were used as materials of cathode substrate, cathode active layer, and electrolyte, respectively. CuO–NiO–SSZ composite anode was deposited on SSZ surface by screen-printing and sintered at 1250 °C for 2 h. The effects of CuO addition to NiO–SSZ anode on the performance of cathode-supported SOFCs were investigated. CuO can effectively improve the sintering activity of NiO–SSZ. The assembled cells were electrochemically characterized with humidified H2 as fuel and O2 as oxidant. With 4 wt.% CuO addition, the ohmic resistance decreased from 3 to 0.46 Ω cm2, and at the same time the polarization resistance decreased from 3.4 to 0.74 Ω cm2. In comparison with the cell without CuO, the maximum power density at 850 °C increased from 0.054 to 0.446 W cm?2 with 4 wt.% CuO addition.  相似文献   

8.
A large area cathode-supported electrolyte film, comprising porous (La0.8Sr0.2)0.95MnO3 (LSM95) cathode substrate, LSM95/Zr0.89Sc0.1Ce0.01O2?x (SSZ) cathode active layer, and SSZ electrolyte, has been successfully fabricated by tape casting and co-sintering techniques. The interface reaction between cathode and electrolyte was inhibited by using A-site deficient LSM. A dense enough SSZ thin film with a thickness of ~26 μm was obtained at 1250 °C. By using Pt as anode, the obtained single cell reached the maximum power density of 0.54 W cm?2 at 800 °C in O2/humidified H2, with open circuit voltage (OCV) value of 1.08 V.  相似文献   

9.
This work reports on a novel chitosan–hematite nanotubes composite film on a gold foil by a simple one-step electrodeposition method. The hybrid chitosan–hematite nanotubes (Chi–HeNTs) film exhibits strong electrocatalytic reduction activity for H2O2. Interestingly, two electrocatalytic reduction peaks are observed at −0.24 and −0.56 V (vs SCE), respectively, one controlled by surface wave and the other controlled by diffusion process. The Chi–HeNTs/Au electrode shows a linear response to H2O2 concentration ranging from 1 × 10−6 to 1.6 × 10−5 mol L−1 with a detection limit of 5 × 10−8 mol L−1 and a sensitivity as high as 1859 μA μM−1 cm−2.  相似文献   

10.
The hydrogen production by water electrolysis was tested with different electrocatalysts (molybdenum, nickel, iron alloys containing chromium, manganese and nickel) using aqueous solutions of ionic liquid (IL) like 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF4). The hydrogen evolution reaction (HER) was performed at room temperature in a potential of −1.7 V (PtQRE). A Hoffman cell apparatus was used to water electrolysis with current density values, j, between 14.6 mA cm−2 (for Ni electrode) and 77.5 mA cm−2 (for Mo electrode). The system efficiency was very high for all electrocatalysts tested, between 97.0% and 99.2%. The energy activation values of HER was determined in an aqueous solution of BMI.BF4 10 vol.%, using platinum (23.40 kJ mol−1) and Mo (9.22 kJ mol−1) as electrocatalysts. The results show that the hydrogen production in IL electrolyte can be carried out with cheap material at room temperature, which makes this method economically attractive.  相似文献   

11.
Poly (neutral red) nanowires (PNRNWs) have been synthesized for the first time by the method of cyclic voltammetric electrodeposition using porous anodic aluminum oxide (AAO) template and were examined by scanning electron microscopy (SEM) and transmission electron microscope (TEM). Moreover, horseradish peroxidase (HRP) was encapsulated in situ in PNRNWs (denoted as PNRNWs–HRP) by electrochemical copolymerization for potential biosensor applications. The PNRNWs showed excellent efficiency of electron transfer between the HRP and the glassy carbon (GC) electrode for the reduction of H2O2 and the PNRNWs–HRP modified GC electrode showed to be excellent amperometric sensors for H2O2 at −0.1 V with a linear response range of 1 μM to 8 mM with a correlation coefficient of 0.996. The detection limit (S/N = 3) and the response time were determined to be 1 μM and <5 s and the high sensitivity is up to 318 μA mM−1 cm−2.  相似文献   

12.
A robust and effective composite film based on gold nanoparticles (GNPs)/room temperature ionic liquid (RTIL)/multi-wall carbon nanotubes (MWNTs) modified glassy carbon (GC) electrode was prepared by a layer-by-layer self-assembly technique. Cytochrome c (Cyt c) was successfully immobilized on the RTIL-nanohybrid film modified GC electrode by electrostatic adsorption. Direct electrochemistry and electrocatalysis of Cyt c were investigated. The results suggested that Cyt c could be tightly adsorbed on the modified electrode. A pair of well-defined quasi-reversible redox peaks of Cyt c was obtained in 0.10 M, pH 7.0 phosphate buffer solution (PBS). RTIL-nanohybrid film showed an obvious promotion for the direct electron transfer between Cyt c and the underlying electrode. The immobilized Cyt c exhibited an excellent electrocatalytic activity towards the reduction of H2O2. The catalysis currents increased linearly to the H2O2 concentration in a wide range of 5.0 × 10−5– 1.15 × 10−3 M. Based on the multilayer film, the third-generation biosensor could be constructed for the determination of H2O2.  相似文献   

13.
A new ferrocenecarboxylic acid–C60 composite (Fc–C60) has been synthesized by controlled potential electrolysis. A composite modified glassy carbon electrode has been prepared based on its good electrochemical activity. The modified electrode in 0.1 M NaClO4 solution shows a reversible oxidation wave at E1/2 = 0.32 V (vs. SCE) attributed to the oxidation of the ferrocene entity and a quasi-reversible reduction wave of C60 entity at E1/2 = ?0.54 V (vs. SCE). Electrocatalytic studies show that Fc–C60 at the modified electrode can mediate the reduction of hydrogen peroxide (H2O2), and a broad linear range from 1.2 μM to 21.9 mM for H2O2 were obtained with a determination limit of 2.5 × 10?7 M by amperometry.  相似文献   

14.
Cobalt-free perovskite oxide La0.5Sr0.5Fe0.8Cu0.2O3  δ (LSFC) was applied as both anode and cathode for symmetrical solid oxide fuel cells (SSOFCs). The LSFC shows a reversible transition between a cubic perovskite phase in air and a mixture of SrFeLaO4, a K2NiF4-type layered perovskite oxide, metallic Cu and LaFeO3 in reducing atmosphere at elevated temperature. The average thermal expansion coefficient of LSFC in air is 17.7 × 10 6 K 1 at 25 °C to 900 °C. By adopting LSFC as initial electrodes to fabricate electrolyte supported SSOFCs, the cells generate maximum power output of 1054, 795 and 577 mW cm 2 with humidified H2 fuel (~ 3% H2O) and 895, 721 and 482 mW cm 2 with humidified syngas fuel (H2:CO = 1:1) at 900, 850 and 800 °C, respectively. Moreover, the cell with humidified H2 fuel demonstrates a reasonable stability at 800 °C under 0.7 V for 100 h.  相似文献   

15.
Electrode–electrolyte hetero-epitaxial systems for solid oxide fuel cells (SOFCs) with two different configuration of Nd2NiO4 + δ(110)//YSZ(100) and Nd2NiO4 + δ(100)//YSZ(110) were successfully fabricated by pulsed laser deposition. Thin films of Nd2NiO4 + δ approximately 20 nm thick were grown on a commercial single crystal of YSZ. The preferred two-dimensional diffusion paths of the oxide ions were perpendicular to the substrate for both configurations and showed oxygen reduction capability different from each other. This opens up new research direction focusing on the details of anisotropic catalytic activity of SOFC cathode depending on the crystalline surface.  相似文献   

16.
Micro-tubular solid-oxide fuel cell consisting of a 10-μm thick (ZrO2)0.89(Sc2O3)0.1(CeO2)0.01 (ScSZ) electrolyte on a support NiO/(ScSZ) anode (1.8 mm diameter, 200 μm wall thickness) with a Ce0.8Gd0.2O1.9 (GDC) buffer-layer and a La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF)/GDC functional cathode has been developed for intermediate temperature operation. The functional cathode was in situ formed by impregnating the well-dispersed nano-Ag particles into the porous LSCF/GDC layer using a citrate method. The cells yielded maximum power densities of 1.06 W cm−2 (1.43 A cm−2, 0.74 V), 0.98 W cm−2 (1.78 A cm−2, 0.55 V) and 0.49 W cm−2 (1.44 A cm−2, 0.34 V), at 650, 600 and 550 °C, respectively.  相似文献   

17.
A direct borohydride fuel cell with a Pd/Ir catalysed microfibrous carbon cathode and a gold-catalysed microporous carbon cloth anode is reported. The fuel and oxidant were NaBH4 and H2O2, at concentrations within the range of 0.1–2.0 mol dm−3 and 0.05–0.45 mol dm−3, respectively. Different combinations of these reactants were examined at 10, 25 and 42 °C. At constant current density between 0 and 113 mA cm−2, the Pd/Ir coated microfibrous carbon electrode proved more active for the reduction of peroxide ion than a platinised-carbon one. The maximum power density achieved was 78 mW cm−2 at a current density of 71 mA cm−2 and a cell voltage of 1.09 V.  相似文献   

18.
An interesting mode of reactivity of MnO2 nanoparticles modified electrode in the presence of H2O2 is reported. The MnO2 nanoparticles modified electrodes show a bi-direction electrocatalytic ability toward the reduction/oxidation of H2O2. Based on this property, a choline biosensor was fabricated via a direct and facile electrochemical deposition of a biocomposite that was made of chitosan hydrogel, choline oxidase (ChOx) and MnO2 nanoparticles onto a glassy carbon (GC) electrode. The biocomposite is homogeneous and easily prepared and provides a shelter for the enzyme to retain its bioactivity. The results of square wave voltammetry showed that the electrocatalytic reduction currents increased linearly with the increase of choline chloride concentration in the range of 1.0 × 10−5 –2.1 × 10−3 M and no obvious interference from ascorbic acid and uric acid was observed. Good reproducibility and stability were obtained. A possible reaction mechanism was proposed.  相似文献   

19.
Electrochemical cells with two ion-selective electrodes, a cation ion-selective electrode against an anion ion-selective electrode, were used to measure the activity coefficient of amino acids in aqueous electrolyte solutions. Activity coefficient data were measured for (H2O + NaBr + glycine) and (H2O + NaBr + l-valine) at T=298.15 K. The maximum concentrations of sodium bromide, glycine, and l-valine were (1.0, 2.4, and 0.4) mol · kg−1, respectively. The results show that the presence of an electrolyte and the nature of both the cation and the anion of the electrolyte have significant effects on the activity coefficients of amino acid in aqueous electrolyte solutions.  相似文献   

20.
Hydrogen peroxide-fuel cell (H2O2-FC) possesses a theoretical power generating efficiency of 119% much larger than hydrogen/oxygen (H2/O2)-FC (82.9%) with a thermodynamic electromotive force of 1.09 V. This communication presents the prototype of H2O2-photofuel cell (PFC) without using noble metal catalyst. The H2O2-PFC is comprised of mesoporous anatase TiO2 nanocrystalline film coated on fluorine-doped tin oxide electorode (mp-TiO2/FTO, photoanode), glassy carbon (cathode), and an aqueous electrolyte solution containing 0.1 M NaClO4 and 0.1 M H2O2. Under UV-light irradiation, the H2O2-PFC stably works, providing a short-circuit current of 0.24 mA cm 2 and an open-circuit voltage of 0.72 V at ambient temperature and pressure, while current hardly flows in the dark. Further, the PFC responds to visible-light due to the charge-transfer complex formation of H2O2 on the TiO2 surface.  相似文献   

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