Gas Concentration Cell Research Articles

Sodium Sulfate Mixed with Rare Earth Sulfates(Ln=Y and Gd) and Silicon Dioxide as a Solid Electrolyte for a Sulfur Dioxide Detector

Abstract Sodium sulfate mixed with rare earth sulfates(Ln=Y and Gd) and silicon dioxide exhibits a Na2SO4-I-like phase as well as a small amount of silicon dioxide phase. The former phase is excellent in Na+ ion conduction. The electrical conductivity of the Na2SO4–Ln2(SO4)3–SiO2(Ln=Y and Gd) systems is considerably higher than that of pure sodium sulfate. When the Na2SO4–Ln2(SO4)3–SiO2(Ln=Y and Gd) sample is applied as a solid electrolyte for a SO2 gas concentration cell, the measured EMF is in good agreement with the calculated EMF for a SO2 gas concentration range from 0.1% (1000 ppm) to 23%, and 0.32% (3200 ppm) to 10%, respectively.

IONIC CONDUCTION AND ELECTRONIC CONOLUCTION IN THE HIGH IONIC CONDUCTOR OF THE SYSTEM Bi2O3-Y2O3

The ionic electrical conduction in sintered Bi2O3-Y2O3 system for samples containing 20-30 mol% Y2O3 was investigated by means of measurement of ac conductivity and the emf of oxygen gas concentration cell using the specimen tablet as electrolyte. The experimental po2 range from 1 to 10-21 atm for ionic electrical conduction measurement-These materials showed high oxygen ionic conduction, the conductivities for samples containing 22.5-30mol% Y2O3 are many times higher than those of stabilized zirconia ZrO based solid electrolyte at corresponding temperatures. When these materials are used to construct an oxygen concentration cell, the E/E0 is equal to 1 or approaches 1. These values show that the samples containing 22.5 to 30 mol% Y2O3 are nearly pure ionic conductors. The p-type hole conductivity is very small at higher po2 values, so it is negligible. The n-type electronic conduction was investigated by means of coulomb titration technique for Y2O3 27.5 mol% sample We obtained that lg pe＇=-767000/T +665. The pe＇ is equal to 2.6×10-61 atm at 800℃. The n-type electronic conduction is vary small, so that it is also negligible.These materials are proved to be good high ionic conductors.

Formation of high oxide ion conductive phases in the sintered oxides of the system Bi 2O 3 Ln2O 3 ( Ln = LaYb)

The electrical conduction in various phases of the system Bi 2O 3 Ln 2O 3 ( Ln = La, Nd, Sm, Dy, Er, or Yb) was investigated by measuring ac conductivity and the emf of the oxygen gas concentration cell. High-oxide-ion conduction was observed in the rhombohedral and face-centered cubic (fcc) phase in these systems. The fcc phase could be stabilized over a wide range of temperature by adding a certain amount of Ln 2O 3. In these cases, the larger the atomic number of Ln, the lower the content of Ln 2O 3 required to form the fcc solid solution, except in the case of Yb 2O 3. The oxide ion conductivity of this phase decreased with increasing content of Ln 2O 3. Maximum conductivity was obtained at the lower limit of the fcc solid solution formation range in each system, which was more than one order of magnitude higher than those of conventional stabilized zirconias. Lattice parameters of the fcc phase were calculated from the X-ray diffraction patterns. The relationship between the oxide ion conductivity and the lattice parameter was also discussed.

Gas concentration cells for the conversion of ocean wave energy

Abstract The concept of using electrochemical gas concentration cells to convert the mechanical potential energy of ocean waves to electricity using a taut-moored buoy is analyzed. Several idealized embodiments are discussed and one of these is shown to have particular merit. Some results obtained in an experimental program aimed at developing such a system are described. In particular, an electrochemical cell employing the protonically conducting synthetic polymer Nafion, bounded by platinum electrodes, has been studied in a manner which simulates the operation of such a device within a taut-moored buoy subject to ocean waves. It is shown that with some modest engineering advances, this system is indeed capable converting a significant fraction of ocean wave energy into electricity.

Sensing sulfur oxides and other sulfur-bearing pollutants with solid electrolyte pellets—I. Gas concentration cells

Sensing sulfur oxides and other sulfur-bearing pollutants with solid electrolyte pellets—I. Gas concentration cells

Sensing sulfur oxides and other sulfur bearing pollutants with solid electrolyte pellets—I. Gas concentration cells

A new sensing technique using a solid electrolyte has been demonstrated for sulfur-bearing pollutants. Based on potentiometric measurements across a pellet of potassium sulfate, this sensor allows concentrations of sulfur dioxides, sulfur trioxide, hydrogen sulfide, methyl mercaptan and carbonyl sulfide in air to be measured with accuracy. Its operational concentration range at the present time is 0.1 ppm up to at least 10000 ppm. The presence of other common pollutants such as carbon dioxide, methane, nitric oxide and nitrogen dioxide does not interfere with the measurement of air samples containing sulfur-bearing pollutants.

Oxide ion conduction in the sintered oxides of MoO3-doped Bi2O3

In order to examine the conduction behaviour in the sintered oxides of MoO3-doped Bi2O3, the electrical conductivity in air and the EMF of oxygen gas concentration cell were measured with respect to the phase relation determined by X-ray diffraction.

Electrical conduction in the sintered oxides of the system Bi 2O 3BaO

The electrical conduction in various phases of the system Bi 2O 3BaO was investigated by measurement of a-c conductivity and the EMF of oxygen gas concentration cell and observation of X-ray diffraction patterns. High oxide-ion conduction was observed in the rhombohedral phase present in 20–25-mol% BaO and hole conduction was observed in the perovskite-type phase based on 2BaO·Bi 2O 3. The oxide-ion conductivity of the 20-mol% BaO specimen was 1.1 × 10 −2 mho/cm at 500°C and the contribution of electronic conductivity to total conductivity was negligibly small in air. In the remaining range of composition, where the monoclinic and rhombohedral mixed phase was found for less than 20-mol% BaO and the rhombohedral and perovskite-type structure mixed phase was observed for more than 28-mol% BaO, the conduction was attributed to oxide ion and electron hole. High oxide-ion conduction in the rhombohedral phase was considered to be due to an appreciable amount of oxide-ion vacancies in this phase.

Determination of the CO2 dissociation pressures of molten carbonates by an EMF technique

A study is reported of the CO2 dissociation pressures for molten carbonates using an emf technique. In the gas concentration cell Au/O2(CO2)diss/CO32−/CO2, O2/Pt, the conditions are adjusted so that the CO2 in the Au compartment is due to the carbonate dissociation. It is shown that EoAu(CO2/O2) = EoPt(CO2/O2) and it follows that this technique may thus be used to monitor the CO2 dissociation pressures of the electrolyte in a continuous manner, with minimum disturbances. The method appears particularly suited for very low dissociation pressure measurements.

NH4Cl, a Mixed Conductor

Pure and barium-doped single crystals of NH4Cl were grown from alkaline and acid aqueous solutions. Electromotive-force measurements of H2, NH3 gas concentration cells with NH4Cl as a solid electrolyte give the transference numbers of ionic, protonic, and electronic conduction in NH4Cl as f(PH2, PNH3). Measurements of the conductivity in controlled atmospheres of H2 and NH3 as f(T) show a dependence on the gas composition in one case only. It is attempted to interpret the results on the basis of simple defect models.