Basic Electrolyte Solution Research Articles

Cobalt sulphide microtube array as cathode in photoelectrochemical water splitting with photoanodes

A CoS microtube electrode catalyses hydrogen evolution efficiently in both neutral and basic aqueous electrolyte solutions. The microtubular CoS electrode was also combined with a hematite photoanode to give a photoelectrochemical water splitting cell.

Experimental investigation of mass transfer of active ions in silica nanofluids

In this paper the effect of silica nanoparticles on mass transfer was studied in circular tube by using electrochemical limiting current technique in both laminar and turbulent flow regimes. Underdeveloped concentration and fully developed hydrodynamic profile was considered. Silica nanoparticles with the size range of 7–13nm was used to prepare electrolyte nanofluid. Base fluid was composed of equimolar potassium ferri-ferrocyanide and sodium hydroxide. Measurements for laminar regime indicated that mass transfer coefficient increased with nanofluid volume fraction up to 0.0057% and decreased with increasing the volume fraction of nanoparticles further. Maximum enhancement in mass transfer reached 21% at Reynolds number of 326. In turbulent flow regime no enhancement was recognized due to the addition of silica nanoparticles to the base electrolyte solution.

BODIPY-Sensitized Photocharging of Anthraquinone-Populated Polymer Layers for Organic Photorechargeable Air Battery

Photocharging of anthraquinone (AQ)-populated polymers was accomplished by incorporating chromophores with redox potentials suitable for the 2e− reduction of the AQ pendants near −1 V versus Ag/AgCl in aqueous basic electrolytes. The photoactive polymers were designed to exhibit redox-isolated behaviors and reversible charge–discharge responses, either by employing a polyacetylene main chain with the π–π* absorption bands in a visible region, or with an aliphatic chain incorporating a BODIPY dye in the form of a multilayer. The charge storage density was maximized by minimizing the molecular weight of the compact repeating units, thus reducing the redox site-to-site distance to allow redox gradient-driven electron self-exchange reactions to proceed throughout the slab of the polymer layer. Homogeneous layers of poly(2-ethynylanthraquinone) and poly(2-vinylanthraquinone) were both sufficiently robust for charge storage application, swellable, and yet insoluble in aqueous basic electrolyte solutions. Such properties allowed the accommodation of external cations from the electrolyte to permeate through the layer for electroneutralization of the negative charge produced by the electroreduction, which led to the repeatable charging and discharging cycles of the photoanodes without degradation of the charge storage capabilities. By virtue of the swelling properties of the polymer layers in the basic aqueous electrolyte, exploration of the aqueous electrochemistry and photochemistry of AQ that had been inaccessible by the lack of the solubility in H2O became feasible. A striking feature of the photoanodes was the capability of employing a hydroxide ion (OH−) as the sacrificial reducing agent, which enabled the use of the O2/OH− redox couple for the cathode reaction during discharging. Combination of the photoanodes with the MnO2/carbon composite cathode, sandwiching the electrolyte layer of aqueous KOH, gave rise to photorechargeable battery effect under irradiation and repeatable discharging with the consumption of O2 at the cathode.

Investigation of Electroreduction Kinetics of the Hexaamminecobalt(III) Cations on the Electrochemically Polished Bi Planes by the Electrochemical Impedance Spectroscopy Method

Electrochemical impedance spectroscopy has been used for investigation of electroreduction kinetics of hexaamminecobalt(III) cations on the electrochemically polished Bi planes. The total charge transfer resistance obtained depends noticeably on the electrode potential and [Co(NH3)6]3+ concentration. Systematic analysis of results show that the equivalent circuit taking into account the adsorption of one reacting or intermediate particle is the more probable and simplest physical model of the complicated [Co(NH3)6]3+ electroreduction reaction under discussion. The charge transfer resistance, adsorption capacitance and adsorption resistance values depend on the electrode potential as well as on the reactant concentration. In the base electrolyte solution with addition of [Co(NH3)6]3+ the adsorption and charge transfer resistance value was maximal and the adsorption capacitance value was minimal in the region of zero charge potential for Bi single crystal (111) and (011-) planes.

Electrochemical synthesis and photocatalytic behavior of flower shaped ZnO microstructures

Flower shaped zinc oxide (ZnO) microstructures have been synthesized via electrochemical method by electrolyzing an aqueous solution of sodium nitrate using sacrificial zinc anode and steel cathode. Investigation on the effect of current density showed that flower shaped structures were formed at lower current density, while irregular ZnO clusters were formed in addition to flowers at higher current densities. Well defined microflowers were formed in neutral and basic electrolyte solutions than in acidic solution. The FESEM results revealed that the flower shaped microstructures have a diameter of ~2–3μm and possess several fusi form petals of ~1–2μm length. Photocatalytic behavior of the synthesized product was investigated through Levafix Blue CA (LB) dye degradation under UV light. The effect of operating parameters like the catalyst load and the initial dye concentration on the rate of dye degradation was studied. Nearly 100% decolorization and ~95% Chemical Oxygen Demand (COD) removal were achieved under optimum experimental conditions, which suggest potential photocatalytic behavior of the synthesized ZnO.

Electrocatalytic Hydrogen Redox Chemistry on Gold Nanoparticles

Electrocatalytic proton reduction leading to the formation of adsorbed molecular hydrogen on gold nanoparticles of 1-3 and 14-16 nm diameter stabilized by 1-mercapto-undecane-11-tetra(ethyleneglycol) has been demonstrated by cyclic voltammetry using a hanging mercury drop electrode. The nanoparticles were adsorbed to the electrode from aqueous dispersion and formed robust surface layers transferrable to fresh base electrolyte solutions. Unique electrocatalytic proton redox chemistry was observed that has no comparable counterpart in the electrochemistry of bulk gold electrodes. Depending on size, the nanoparticles have a discrete number of electrocatalytically active sites for the two-electron/two-proton reduction process. The adsorbed hydrogen formed is oxidized with the reverse potential sweep. These findings represent a new example of qualitative different behavior of nanoparticles in comparison with the corresponding bulk material.

Influence of surface modification of LiCoO2 by organic compounds on electrochemical and thermal properties of Li/LiCoO2 rechargeable cells

LiCoO2 is the most famous positive electrode (cathode) for lithium ion cells. When LiCoO2 is charged at high charge voltages far from 4.2V, cycleability of LiCoO2 becomes worse. Causes for this deterioration are instability of pure LiCoO2 crystalline structure and an oxidation of electrolyte solutions LiCoO2 at higher charge voltages. This electrolyte oxidation accompanies with the partial reduction of LiCoO2. We think more important factor is the oxidation of electrolyte solutions. In this work, influence of 10 organic compounds on electrochemical and thermal properties of LiCoO2 cells was examined as electrolyte additives. As a base electrolyte solution, 1M (M: molL−1) LiPF6-ethylene carbonate (EC)/ethylmethyl carbonate (EMC) (mixing volume ratio=3:7) was used. These compounds are o-terphenyl (o-TP), Ph-X (CH3)n (n=1 or 2, X=N, O or S) compounds, adamantyl toluene compounds, furans and thiophenes. These additives had the oxidation potentials (Eox) between 3.4 and 4.7V vs. Li/Li+. These Eox values were lower than that (6.30V vs. Li/Li+) of the base electrolyte. These additives are oxidized on LiCoO2 during charge of the LiCoO2 cells. Oxidation products suppress the excess oxidation of electrolyte solutions on LiCoO2. As a typical example of these organic compounds, o-TP (Eox: 4.52V) was used to check the fundamental properties of these organic additives. Charge–discharge cycling tests were carried out for the Li/LiCoO2 cells with and without o-TP. Constant current charge at 4.5V is mainly used as a charge method. Cells with 0.1wt.% o-TP exhibited slightly better cycling performance and lower polarization than those without additives. Lower polarization arises from a decrease in a resistance of interface between electrolyte solutions and LiCoO2 by surface film formation resulted from oxidation of o-TP. Oxidation products were found by mass spectroscopy analysis to be mixture of several polycondensation compounds made from two to four terphenly monomers. Thermal stability of LiCoO2 with electrolyte solutions did not improve by addition of o-TP. Slightly better charge–discharge cycling properties were obtained by using organic modifiers. However, when industrial applications were considered, drastic improvements have not been obtained yet. One of reasons may be too large influence of the deterioration of stability of pure LiCoO2 structure at high voltage charging for industrial use. We hope to realize the tremendous improvements of high energy, long cycle life and safe lithium cells by the combination of both LiCoO2 with more stable structure such as LiCoO2 treated with MgO and new organic additives with molecular structure more carefully designed.

Modeling the phase equilibria of CO2 and H2S in aqueous electrolyte systems at elevated pressure

Abstract The solubility of carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) in basic aqueous electrolyte solutions is determined by a combined phase and reaction equilibrium. A cubic equation of state is applied to model the vapor-liquid equilibria of these reacting systems. The Peng-Robinson equation of state with Wong-Sandler mixing rules is combined with an extended UNIQUAC model for electrolytes where ion-specific interactions are determined from a Debye-Huckel term. The thermodynamic model is parameterized for aqueous systems containing carbon dioxide and hydrogen sulfide along with water and potassium carbonate solutions at high pressure. The UNIQUAC binary interaction parameters are estimated by minimizing deviations in the liquid phase composition of the model with respect to the experimental data. The data is taken from literature and is supplemented by own experimental work conducted as part of this study.

The Development of a Novel in vitro Model Using Kidney Biopsy Specimens to Study the Effects of Warm and Cold Ischaemia on the Kidney

Traditional experimental methods of assessing renal function typically rely on whole kidneys and subsequent measures of glomerular fi ltration rate. In this study, we measured the viability of kidney biopsy samples of fi xed length using formazan-based colorimetry in an attempt to evaluate the suitability of this assay in predicting whole organ viability. A series of experiments were set up to study the response of the ischaemic rabbit kidney tissue of fi xed length (5 mm) obtained using a 16-gauge needle to various preservative solutions at various temperatures. Samples were maintained at 37 °C in a Hereaus EK/O2 incubator in an atmosphere of 5% CO2 in air, or at 1–4 °C in a Labheat incubator (Borolabs, U.K.) or at 20 °C in air for up to 96 hours. The formation of formazan within renal biopsy cores was most rapid during the fi rst hour and then levelled off for the rest of the assay period (4 hours). Formazan formation was marginally more from renal cortex than medulla, although the differences were not statistically signifi cant. The viability of kidney tissue was temperature dependent such that incubating a non-perfused kidney for 20 hours resulted in a 90% reduction in formazan formation and therefore viability at 37 °C compared to 1 °C. Formazan formation from rabbit kidney biopsy samples taken on day 0 and placed singly wells of a 24 well fl at-bottomed tissue culture plate containing 1.8 ml of preservative solution was assessed daily for 4 days. This was compared with the viability of tissue taken daily from whole kidneys perfused with the same preservative solution. Initial viability assessments were similar as were changes with time. This assay was able to demonstrate the superiority of the currently available renal preservative solutions Soltran and Viaspan in maintaining the viability of renal tissue at low temperatures compared with other randomly selected solutions. In conclusion, maintaining freshly obtained renal biopsy samples in a tissue culture system is a cheap, convenient and potentially useful model of renal ischaemia. Biochemical tests of cellular viability including formazan based colorimetry on isolated tissue may offer the opportunity to study the effects of ischaemia on the kidney, and may aid in the development of drugs for treating renal ischaemia. Introduction Research on the effects of ischaemia on the kidney and possible treatments for this, has been hampered by the lack of a suitable simple and inexpensive model. Traditionally such research has depended on the use of complicated surgical techniques on living animals followed by cumbersome assessments of glomerular function (Lieberthal et al. 1988; Cassie et al. 1959). Warm renal ischaemic damage is a common clinical problem often occurring as a consequence of hypotension, surgery, sepsis, dehydration or haemorrhage and presenting as acute renal failure (ARF). Despite considerable experimental study, there are no drugs in routine clinical use with proven effi cacy for abrogating the effects of this type of ischaemic damage on the kidney (Bates and Lin, 2005: Suzuki et al. 2005). Although most patients with ARF recover spontaneously, they often require a high level of expensive clinical care. Furthermore, ARF may be associated with high mortality rates (Metcalfe et al. 2002). Prior to kidney transplantation, retrieved organs are ordinarily perfused with cold solutions to preserve them. These are fairly basic electrolyte solutions containing a few novel chemical agents.

Electrochemical quartz crystal microbalance studies of a palladium electrode oxidation in a basic electrolyte solution

Anodic oxidation of Pd in basic solutions (0.1 M KOH aq and 0.1 M NaOH aq) has been examined via cyclic voltammetry (CV) and an electrochemical quartz crystal microbalance (EQCM). Admittance tests show that Pd(II) layer behaves as a rigid one. The anodic vertex potential influences mass response during formation of the Pd(II) layer. For low anodic vertex potentials, obtained absolute mass per mole values suggest Pd(OH) 2 or PdO·H 2O to be oxidation products. At this stage of the oxidation process, contribution from adsorbed H 2O/OH − in Pd(II) layer formation could explain the lower-than-expected mass gain, although the extent of H 2O/OH − adsorption is unclear. The mass gain decreases with further increase in the anodic vertex potential, eventually reaching the value of ca. 8 g mol −1 at about 700 mV vs. SCE. Comparing the influence of vertex potential in CV experiments on the mass and reduction potential of the Pd(II) species points to the formation of PdO at higher oxidation potentials. At this stage of the process, a fraction of the PdO species is generated during transformation of previously formed Pd(OH) 2/PdO·H 2O. A shift of the main Pd(II) reduction potential peak depends on both the anodic vertex potential and on the composition of the Pd(II) film. The order of the Pd(II) reduction process is the opposite of that observed for the oxidation process. The Pd(IV) species formed at E ≥ 500 mV vs. SCE and those reduced between 50 and 350 mV are hydrated or contain hydroxyl groups.

Electrochemical deposition characteristics of p-CuSCN on n-ZnO rod arrays films

p-CuSCN/n-ZnO rod array heterojunctions were electrodeposited with a weak basic (pH ∼9) aqueous electrolyte solution. I– V characteristics showed the heterostructure had clear rectification, indicating good electrical contacts between ZnO rod arrays and the embedded CuSCN. The energy band model for the electrodeposition of CuSCN on ZnO rod arrays was proposed based on linear sweep voltammetric (LSV) measurements, which indicated that the electrodeposition process was the prior growth of CuSCN on bare ZnO rods according to a conduction process, followed by compact filling in the gaps of the arrays based on the thermal activation mechanism of surface states. The diode properties of the heterojunctions revealed that although deposition was dominated by thermal activation mechanism of surface states, the electrodeposition should be performed at a lower temperature in order to reach fine filling of the gaps of ZnO rod arrays.

Hysteresis in a Carbon Nanotube Based Electroactive Polymer Microfiber Actuator: Numerical Modeling

Hysteretic behavior is an important consideration for smart electroactive polymer actuators in a wide variety of nano/micro-scale applications. We prepared an electroactive polymer actuator in the form of a microfiber, based on single-wall carbon nanotubes and polyaniline, and investigated the hysteretic characteristics of the actuator under electrical potential switching in a basic electrolyte solution. For actuation experiments, we measured the variation of the length of the carbon-nanotube-based electroactive polymer actuator, using an Aurora Scientific Inc. 300B Series muscle lever arm system, while electrical potentials ranging from 0.2 V to 0.65 V were applied. Based on the classical Preisach hysteresis model, we presented and validated a numerical model that described the hysteretic behavior of the carbon-nanotube-based electroactive polymer actuator. Inverse hysteretic behavior was also simulated using the model to demonstrate its capability to predict an input from a desired output. This numerical model of hysteresis could be an effective approach to micro-scale control of carbon-nanotube-based electroactive polymer actuators in potential applications.

Microporous activated carbons from ammoxidised anthracite and their capacitance behaviours

The paper presents results of a study on obtaining N-enriched active carbons from anthracite mined in Siberia, and on its use as electrode material in supercapacitors. The anthracite was carbonised, activated with KOH and ammoxidised by a mixture of ammonia and air at the ratio 1:3 at 300 or 350 °C, at each stage of the activate production. The products were microporous N-enriched active carbon samples of well-developed surface area reaching from 1255 m 2/g to 2011 m 2/g and containing from 0.3 to 5.4 wt% of nitrogen. Capacity curves characteristics of the ammoxidised active carbon samples were determined by the galvanostatic and potentiodynamic methods, and by impedance spectroscopy for acidic and basic electrolyte solutions. The best capacity parameters in an acidic medium were obtained for the coal samples ammoxidised at the precursor stage (191 F/g), containing about 0.4 wt% of nitrogen, while in a basic medium—for the coal samples ammoxidised at the stage of active carbon (200 F/g), containing 4.0 wt% of nitrogen.

Adsorption of 1,6-hexanediol on Bi single crystal electrodes

Cyclic voltammetry (CV) and electrochemical impedance spectroscopy have been employed for the quantitative study of 1,6-hexanediol (HD) adsorption at the Bi(0 0 1) and Bi(l 1 1)|0.05 M Na 2SO 4 aqueous solution interfaces. According to the experimental data the Bi(l 1 1) interface has more negative zero charge potential and the adsorption–desorption peaks appear at more negative potentials than in case of Bi(0 0 1) interface. However, the adsorption activity is practically similar for Bi(0 0 1) and Bi(l 1 1) planes. The surface area occupied by one adsorbed molecule S max equal to 0.47 nm 2 at the maximum adsorption potential indicates that HD molecules have flat orientation on Bi( h k l) surfaces. For less concentrated solutions the capacitance decreases in the maximum adsorption area as HD concentration increases, but in case of HD concentrations above 0.5 M the capacitance starts to increase. Cyclic voltammetry results show the capacitive adsorption and desorption peaks at higher potential scan rates for solutions with addition of HD in the base electrolyte solution.

Effect of O2 Flow Concentration during Reactive Sputtering of Ni Oxide Thin Films on Their Electrochemical and Electrochromic Properties in Aqueous Acidic and Basic Electrolyte Solutions

Thin films of Ni oxide were deposited by reactive sputtering in argon/oxygen gas mixtures using O2 flow concentrations ranging from 6 to 100% and their electrochemical and electrochromic properties were examined using dilute acidic (1 M KCl+0.5 mM H2SO4) and basic (1 M KOH) aqueous electrolyte solutions. An electrochromic coloration efficiency of 32±5 cm2/C was obtained for all the Ni oxide films regardless of O2 concentration in both KCl+H2SO4 and KOH. The charge capacity and resultant change in the optical density of the Ni oxide films increased with O2 concentration owing to a decrease in crystal grain size and the resultant increase in the active surface area of the NiO crystal grains. Although the interfacial capacitances of the Ni oxide films in KCl+H2SO4 are 2–3 times less than those in KOH, a maximum change in optical density of 0.57 was obtained in KCl+H2SO4 for a fine-grained Ni oxide film with a thickness of 400 nm sputtered in 100% O2.

A novel “dual mode” actuation in chitosan/polyaniline/carbon nanotube fibers

Fibers composed of chitosan, polyaniline (PANi), and single-wall carbon nanotubes (SWNTs) have been fabricated using a wet spinning method. We investigated the structural properties, morphology, and mechanical properties of the fibers using Raman spectroscopy, environmental scanning electron microscopy (ESEM), and tensile testing, respectively. The conductivity and electroactivity of the fibers were studied using the four-point probe method and cyclic voltammetry. The actuation of the fibers during pH switching in acidic or basic electrolyte solutions with and without applied electrical potential was determined. For the first time, a dual mode actuation is reported. The pH switching showed large strains due to the protonation/deprotonation of amine groups of the chitosan. In addition, a second strain response was produced by redox reactions of the PANi. Dual mode actuation is useful in practice, as it allows independent small scale adjustment of the pH induced large strains. The carbon nanotubes improved the conductivity and mechanical strength of the fibers.

Poly-ether modified siloxanes as electrolyte additives for rechargeable lithium cells

Influence of four poly-ether modified siloxanes as electrolyte additives on charge–discharge cycling properties of lithium was examined. As siloxanes, diethylene glycol methyl-(3-dimethyl(trimethylsiloxy)silyl propyl)ether (sample A), diethylene glycol methyl-(3-dinethyl(trimethylsiloxy)silyl propyl)-2-methylpropyl ether (sample B), diethylene glycol methyl-(3-bis(trimethylsiloxy)silyl propyl)ether (sample C) and diethylene glycol-(3-methyl-bis(trimethylsiloxy)silyl-2-methylpropyl)ether (sample D) were investigated. As a base electrolyte solution, 1 M (M, mol L −1) LiPF 6-ethylene carbonate (EC)/methylethyl carbonate (MEC) (mixing volume ratio = 3:7) was used. As the anodes, lithium metal, natural graphite carbon and silicon–SiO 2–carbon (Si–C) composite electrodes were used. Lithium cycling efficiencies of these three anodes improved and an impedance of anode/electrolyte interface decreased by adding poly-ether modified siloxanes. Graphite/LiCoO 2 and Si–C/LiCoO 2 cells exhibited better anode utilization and good cycling performance by using 1 M LiPF 6–EC/MEC + siloxane electrolytes. It was also found that thermal stability of the electrolyte solutions improved by adding siloxanes. Thermal decomposition temperature of 1 M LiPF 6–EC/MEC shifted to higher temperature by adding siloxanes. Amount of heat-output of graphite–lithium anodes with M LiPF 6–EC/MEC electrolyte solutions decreased and the temperature starting the heat-output shifted to higher temperature by adding siloxanes. Among siloxanes examined here, samples B and D exhibited much better performance.

Electroreduction of Hexaamminecobalt(III) Cation on Bi ( hkl ) Electrodes from Weakly Acidified LiClO4 Solutions

The cyclic voltammetry and rotating disk electrode methods have been used for investigation of electroreduction kinetics of the hexaamminecobalt(III) cations on the electrochemically polished Bi planes. The rate constant for the heterogeneous electroreduction reaction of the cation on the Bi(001) and planes in M aqueous base electrolyte solutions has been established and the results have been compared with the data for the Ag(110), , and Hg electrodes as well as with the data for in M solutions. In the region of zero charge potential, the value of the experimental transfer coefficient is slightly higher than 0.5 and depends on the crystallographic structure of the Bi plane. For more concentrated base electrolyte solutions, the values of apparent transfer coefficient , corrected for the double-layer effect, are practically independent of the base electrolyte concentration and slightly depend on the electrode polarization. Noticeably different values of the double-layer-corrected rate constant and for the Bi(001), , Bi(111), Hg, and Ag(110) electrodes from the data for planes have been explained by the different water and adsorption energies at the metals under discussion.

Anomalous pH Actuation of a Chitosan/SWNT Microfiber Hydrogel with Improved Mechanical Property

AbstractComposite fibers composed of chitosan and single-wall carbon nanotubes (CNTs) have been fabricated using a wet spinning method. The dispersion was improved by the sonic agitation of the CNTs in a chitosan solution followed by centrifugation to remove tube aggregates and any residual catalyst. The mechanical behavior was investigated using a dynamic mechanical analyzer (DMA). The mechanical tests showed a dramatic increase in Young's modulus for the chitosan/CNT composite fibers fabricated using the improved dispersion method. The strain on the microfibers was determined from tensile load measurements during pH switching in acidic or basic electrolyte solutions. The microfibers showed a general actuation behavior of expanding at pH = 2 and contracting at pH = 7 under low tensile loads. However, a reverse of this actuation behavior was exhibited under high tensile loads. This anomalous pH actuation is both new and surprising. It was explained from an analysis of the differences in sample stiffness and Poisson’s ratio under tensile load in electrolyte solutions with different pH values.

Platinum black coated microdisk electrodes for the determination of high concentrations of hydrogen peroxide in phosphate buffer solutions

The performance of a series of platinum black coated microdisk electrodes (Pt-Bs) was investigated in H 2O 2 solutions over the concentration range 0.1–500 mM, in phosphate buffer media pH 7. The Pt-Bs were prepared by electrodeposition of Pt onto the surface of microdisk electrodes 12.5 μm of nominal radius, from aqueous solutions containing hexachloroplatinic acid. The resulting roughness factors (RF, i.e., the ratio of the effective surface area to the geometric electrode area) varied between about 10 and 100. The voltammograms recorded with these electrodes, at relatively low H 2O 2 concentrations (up to 50–100 mM), displayed rather steep mixed anodic–cathodic waves, which attained well-defined and stable current plateaus. At the higher hydrogen peroxide concentrations, additional waves both in the anodic and cathodic region or dramatic current drop phenomena were observed. The wave split phenomenon was attributed to the insufficient buffering capacity of the base electrolyte solution within the pores of the platinum black, induced by the large amounts of hydrogen ions produced in the oxidation process. The current drop was attributed to either the formation of oxygen bubbles, which limit diffusion of H 2O 2 down the pores, or saturation of the active sites responsible for the decomposition of H 2O 2 to O 2 and H 2O. The H 2O 2 concentration at which the above phenomena occurred depended either on the phosphate buffer concentration in the bulk solution or the RF factor of the electrodes. The latter conditions also affected the dynamic range of detection, the sensitivity and low detection limits. Advantageous analytical characteristics were obtained with a Pt-B of RF of about 24, which provided a dynamic range between 0.5 and 230 mM, a sensitivity of 1.93(±0.06) A M −1 cm −2 and a low detection limit of 0.05 mM. The reproducibility was also very good, it being within 2–3%. The usefulness of the Pt-Bs for real samples analysis was tested in an antiseptic solution containing large amounts of H 2O 2.