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Guiqiang Wang - One of the best experts on this subject based on the ideXlab platform.

  • Performance characteristics of dye-sensitized solar cells with counter Electrode based on NiP-plated Glass and titanium plate
    Current Applied Physics, 2009
    Co-Authors: Guiqiang Wang
    Abstract:

    Abstract The counter Electrodes based on NiP-plated Glass and titanium plate were prepared. The performance characteristics of the dye-sensitized solar cells with platinized NiP-plated Glass Electrode (Pt/NiP Electrode) and platinized titanium plate Electrode (Pt/TP Electrode) were discussed. Pt/NiP Electrode and Pt/TP Electrode showed the same catalytic activity for triiodide reduction compared with platinized fluorine-doped tin oxide conducting Glass Electrode (Pt/FTO Electrode). However, Pt/NiP Electrode and Pt/TP Electrode have the advantage over Pt/FTO Electrode in reducing the sheet resistance and increasing light reflectivity, which resulted in improving the photovoltaic performance of dye-sensitized solar cells effectively. Compared with the cell using Pt/FTO Electrode, the incident photon conversion efficiency of dye-sensitized solar cells with Pt/NiP Electrode and Pt/TP Electrode was increased by 20% and 5%, respectively, the overall energy efficiency of dye-sensitized solar cells with Pt/NiP Electrode and Pt/TP Electrode was increased by 32% and 27%, respectively.

  • Novel counter Electrodes based on NiP-plated Glass and Ti plate substrate for dye-sensitized solar cells
    Journal of Materials Science, 2007
    Co-Authors: Guiqiang Wang
    Abstract:

    Novel counter Electrodes based on NiP-plated Glass and Ti plate substrate were prepared by thermal decomposition of H2PtCl6. Their properties and application in dye-sensitized solar cells were investigated. Platinized Ti plate Electrode (Pt/TP Electrode) and platinized NiP-plated Glass Electrode (Pt/NiP Electrode) exhibited the same electrochemical activity for triiodide reduction as platinized fluorine-dope tin oxide (FTO) conducting Glass Electrode (Pt/FTO Electrode). However, Pt/NiP Electrode and Pt/TP Electrode have the advantage over the Pt/FTO Electrode in increasing the light reflectance and reducing the sheet resistance, which resulted to improve the light harvest efficiency and the fill factor of the dye-sensitized solar cells effectively. Examination of the anodic dissolution indicated the good stability of the Pt/NiP Electrode and Pt/TP Electrode in the electrolyte containing iodide/triiodide.

  • a novel high performance counter Electrode for dye sensitized solar cells
    Electrochimica Acta, 2005
    Co-Authors: Guiqiang Wang, Ruifeng Lin, Yuan Lin, Xiaowen Zhou, Xurui Xiao
    Abstract:

    Abstract A novel Pt counter Electrode for dye-sensitized solar cells (DSC) was prepared by thermal decomposition of H 2 PtCl 6 on NiP-plated Glass substrate. The charge-transfer kinetic properties of the platinized NiP-plated Glass Electrode (Pt/NiP Electrode) for triiodide reduction were studied by electrochemical impedance spectroscopy. Pt/NiP Electrode has the advantage over the platinized FTO conducting Glass Electrode (Pt/FTO Electrode) in increasing the light reflectance and reducing the sheet resistance leading to improve the light harvest efficiency and the fill factor of the dye-sensitized solar cells effectively. The photon-to-current efficiency and the overall conversion efficiency of DSC using Pt/NiP counter Electrode is increased by 20% and 33%, respectively, compared to that of using Pt/FTO counter Electrode. Examination of the anodic dissolution and the long-term test on the variation of charge-transfer resistance indicates the good stability of the Pt/NiP Electrode in the electrolyte containing iodide/triiodide.

Gábor Galbács - One of the best experts on this subject based on the ideXlab platform.

  • The effect of sonication on Glass Electrodes.
    Talanta, 2005
    Co-Authors: Zoltán Galbács, Herman Van Langenhove, Gábor Galbács
    Abstract:

    This communication describes observations made on the disturbing effect of ultrasound on the functioning of Glass Electrodes. It was observed that the signal of Glass Electrodes drops significantly, with as much as several pH units, if sonication is applied to the sample solution. The effect was studied for a variety of electrolyte solutions and for several Glass Electrode makes, and was always found to be reversible and reproducible. The quality and the concentration of the electrolyte, as well as the ultrasonic power applied were seen to strongly influence the magnitude of the effect. These findings suggests that (i) if a Glass Electrode is being used to follow chemical reactions in sonicated solutions, irradiation should be intermitted for the time of measurements, and (ii) the phenomenon may provide an alternative method for sensing ultrasound or mapping ultrasound energy distribution.

Richard G Compton - One of the best experts on this subject based on the ideXlab platform.

  • optimising amperometric ph sensing in blood samples an iridium oxide Electrode for blood ph sensing
    Analyst, 2019
    Co-Authors: Korbua Chaisiwamongkhol, Christopher Batchelormcauley, Richard G Compton
    Abstract:

    Amperometric pH sensing in blood samples has been studied using iridium oxide Electrodes. The iridium oxide Electrodes are made by Electrodeposition of iridium oxide onto an iridium micro-disc Electrode from an alkaline solution of iridium(III) oxide. The response of the Electrode is studied in aqueous solutions and authentic samples of sheep's blood employing both cyclic voltammetry and square wave voltammetry. Uncertainties of pH measurement in blood samples via cyclic voltammetry (±0.07 pH units) were improved by a factor of two using square wave voltammetry (±0.03 pH units). Limitations of amperometric pH sensing in blood samples are considered as caused by the uncertainty of the required reference measurements (via a conventional Glass Electrode) and also the use of matrix-free and low ionic strength buffers to calibrate a standard Glass Electrode for the measurement of blood pH.

F. G. K. Baucke - One of the best experts on this subject based on the ideXlab platform.

  • Functioning of Glass Electrodes. A discussion of interfacial equilibria
    Physics and Chemistry of Glasses, 2001
    Co-Authors: F. G. K. Baucke
    Abstract:

    The central process of the Glass Electrode response, i.e. interfacial equilibrium between functional groups at the Glass surface and hydronium and/or alkali ions in the solution is presented and discussed. Depending on the relative pH and pM it generates a coverage of the surface with the acidic and/or salt form of the surface groups. A minute concentration of anionic groups involved represents a negative charge density at the Glass surface, which generates a membrane potential which is the basis of the Glass Electrode response. A thermodynamic treatment of the interfacial equilibrium reveals that the Glass Electrode response is subideal which gives the sub-Nernstian response a thermodynamic meaning. The practical potential slope consists of two parts, whose magnitudes are obtained from the sub-Nernstian response: the dependence of the potential on the activity of the anionic groups (internal slope') and the dependence of their activity on pH (and pM) in solution. The membrane coverage is described as a function of pH and pM. Due to the minute concentration of the anionic surface groups, their activity coefficient is independent of pH and pM at 100% pH and pM selectivities which explains why the Glass Electrode response is linear in these ranges.

  • Further Insight into the Dissociation Mechanism of Glass Electrodes. The Response in Heavy Water
    The Journal of Physical Chemistry B, 1998
    Co-Authors: F. G. K. Baucke
    Abstract:

    It is shown that the functioning of Glass Electrodes in heavy water reflects the same mechanism as that in light water, the quantitative difference being the isotope effect. The central process of this “dissociation mechanism” is an interfacial equilibrium between surface groups of the membrane Glass and hydronium and/or alkali ions in the solution involving dissociated surface groups whose charge causes the ion activity-dependent potential of the Glass. The dissociation mechanism thus differs from other explanations of the Glass Electrode functioning in that it is based on verified reactions and is not merely a theory. The common Glass Electrode mechanism in the isotopic solvents permits the understanding of empirical methods to determine pD (“deuteron effect”) and pNa(D2O) (“deuterium oxide effect”) in heavy water by the application of correction terms, δGlass and δGlass,Na, which are added, respectively, to the apparent (“operational”) pHD and the pNa(H2O)D2O values measured by Glass Electrode cells ca...

  • The modern understanding of the Glass Electrode response
    Fresenius' Journal of Analytical Chemistry, 1994
    Co-Authors: F. G. K. Baucke
    Abstract:

    Electrochemical experiments in combination with infrared spectroscopy and subsurface concentration profiling yielded information on ionic processes at the membrane surface of Glass Electrodes and resulted in a detailed mechanism of the Glass Electrode response. This “dissociation mechanism” is based on phase boundary equilibria between anionic groups at the Glass surface and hydrogen or alkali ions in the solution, which control the potential of the Glass and the concentrations of ions attached to the surface groups. The resulting concentration gradients between Glass surface and bulk Glass cause an interdiffusion of the different ions, if they are not hindered sterically to penetrate into the Glass, and a diffusion potential beneath the Glass surface. The interdiffusion determines the course of the Glass corrosion, which thus depends on whether protons or alkali ions are attached to the surface and interdiffuse with the alkali ions of the Glass, leading, respectively, to a steady-state leached layer or a continuously growing alkali-exchanged layer. pH Electrodes with La2O3-containing membrane Glasses show delayed interfering potential drifts in neutral and alkali phosphate and fluoride solutions caused by LaPO4 and LaF3 deposits, respectively, at the membrane surface (“phosphate” and “fluoride errors”). Equations for the phase boundary potential and phase boundary concentrations are derived on a thermodynamic and kinetic basis and are verified experimentally. Glass leaching and alkali ion interdiffusion are studied, and the diffusion potential within a leached layer is determined. The formation periods of pH and of pM Glass Electrodes are explained, and an indirect part of the sodium error and an irreversible sodium error are detected. Leached and alkali-exchanged layers consist of modified Glass and are not “gel” layers as generally assumed. Large exchange current densities of the phase boundary equilibria explain the stability of Glass Electrode potentials. Migration experiments with subsequent concentration profiling showed that Glasses can be alkali ion, proton, and mixed alkali ion-proton conductors and yielded concentration-dependent mobilities of lithium ions and replacing protons in a lithium silicate Glass. The unchanged pH response of membranes before and after field-driven protonation, in alkali-free solutions, excludes the exchange of different ions as the origin of the Glass Electrode response, as assumed by the ion exchange theory, and verifies the dissociation mechanism.

Elisabeth Bosch - One of the best experts on this subject based on the ideXlab platform.

  • retention of ionizable compounds on hplc 6 ph measurements with the Glass Electrode in methanol water mixtures
    Journal of Chromatography A, 2001
    Co-Authors: Immaculada Canals, Fadoua Z Oumada, Marti Roses, Elisabeth Bosch
    Abstract:

    s The relationship, d values, between the two rigorous pH scales, pH (pH measured in a methanol-water mixture and s s referred to the same mixture as standard state) and pH (pH measured in a methanol-water mixture but referred to water as w ss standard state), in several methanol-water mixtures was determined (d 5 pH2 pH). d values were measured using a ws combined Glass Electrode and a wide set of buffer solutions. The results are consistent with those obtained with the hydrogen Electrode. This confirms the aptness of the Glass Electrode to achieve rigorous pH measurements in methanol-water mixtures. An equation that relates d and composition of methanol-water mixtures, and allows d computation at any ss composition by interpolation, is proposed. Therefore, pH can be achieved from the experimental pH value and d at any sw ss mobile phase composition. pH (or pH) values are related to the chromatographic retention of ionizable compounds through sw their thermodynamic acid-base constants in the methanol-water mixture used as mobile phase. These relationships were tested for the retention variation of several acids and bases with the pH of the mobile phase. Therefore, the optimization of w the mobile phase acidity for any analyte can be easily reached avoiding the disturbances observed when pH is used. w