Ac Technique Research Articles

Determining Proton Transport in Pseudo Catalyst Layers Using Hydrogen Pump DC and AC Techniques

Optimizing electrode morphology with a more uniform ionomer distribution is key to reducing ohmic losses and increasing electrocatalyst utilization in polymer electrolyte fuel cells (PEFCs). Inherent ionomer conductivity, volume fraction and tortuosity determine effective ionic conductivity. We use hydrogen pump (HP) method to measure effective ionic conductivity of a pseudo catalyst layer (PCL) comprised of Vulcan XC-72 carbon black and 3M 825 EW ionomer with ionomer to carbon (I/C) ratios of 0.6, 1 and 1.4 and relative humidity (RH) range of 50 to 120%. These direct current (DC) experiments are then compared with electrochemical impedance spectroscopy (EIS). Both DC and EIS methods show good agreement, indicating that EIS can be used as an alternative to DC method in HP experiment. Ionic conductivity for PCL with I/C of 1 and 1.4 was found to be about one order of magnitude higher than I/C of 0.6 for most of the RH range. At 90% RH tortuosities for I/C = 1 and 1.4 were close to 1, whereas tortuosity for I/C = 0.6 was 3. With decrease in relative humidity tortuosities increased linearly and at 50% relative humidity a PCL with I/C = 0.6 had the highest tortuosity of 6.1.

Temperature-Dependent Thermal Capacitance Characterization for SOI-MOSFETs

Thermal capacitances are required to describe the fast dynamic thermal behavior in the silicon-on-insulator (SOI) devices. This article presents a physical model based on the ac technique, together with the characteristic thermal frequency determination through the frequency response of the output conductance, for calculating the thermal capacitance of single-finger and multi-finger SOI-MOSFETs. The model accounts for the total gate width and substrate temperature, making evident the augmented thermal coupling when multi-fingers are used. The thermal capacitances and the corresponding time constants, extracted from a variety of gate widths and number of fingers, are correctly predicted up to a substrate temperature of 150 °C.

Densification, morphological and transport properties of functional La1–xBaxYbO3–δ ceramic materials

The effective operation of protonic ceramic electrochemical cells requires the design of electrolytes having not only high ionic conductivity, but also excellent stability with respect to carbonisation. In the present work, the La-based oxides (La1–xBaxYbO3–δ, 0.03 ≤ x ≤ 0.10) are proposed as a possible alternative to the convenient Ba(Ce,Zr)O3-based electrolytes due to their high chemical stability. It was discovered that Ba-doping results in a deterioration of sintering behaviour; as a result, the relative density decreases and open porosity appears (for x = 0.10). A thorough analysis of transport properties by means of AC and DC measurement techniques enables a selection of the La0.97Ba0.03YbO3–δ sample, which demonstrates the highest conductivity compared with those samples where x = 0.5 and 0.10. Due to its excellent densification behaviour, stability and ionic conductivity, La0.97Ba0.03YbO3–δ can be considered as a promising proton-conducting electrolyte in the La-based family.

Characterizing the Li-Solid-Electrolyte Interface Dynamics as a Function of Stack Pressure and Current Density

Summary The replacement of conventional liquid electrolytes with solid electrolytes has the potential to safely enable energy-dense Li-metal anodes. Because of the challenges surrounding solid-solid interfaces, it is crucial to better understand the Li-metal-solid-electrolyte interface. This work utilizes stack pressure to correlate mechanics with the electrochemical behavior of Li-electrolyte cells during galvanostatic cycling. Symmetric cells are constructed using Li7La3Zr2O12 and tested using AC and DC techniques under dynamic stack pressure conditions. It is demonstrated that significant polarization occurs during galvanostatic cycling at a current-dependent “critical stack pressure.” Using reference electrodes, this effect is isolated to the Li stripping electrode. This suggests that at low pressures, the Li stripping rate exceeds the rate at which mechanical deformation replenishes the interface, inducing the formation of voids and ultimately increasing resistance. This analysis not only motivates the need for further understanding of the Li-metal-solid-electrolyte interface but also provides guidelines for the future design of all-solid-state batteries.

SSA-AC

Recently, the quest to reduce energy consumption in digital systems has been the subject of a number of ongoing studies. One of the most researched focuses is approximate computing (AC) . AC is a new computing paradigm in both hardware and software designs that aim to achieve energy-efficient digital systems. Although a variety of AC techniques have been studied so far, the main question, “How (in which section) can a program or a circuit be approximated?,” has not been answered yet. This work addresses the above issue by developing a software framework Static Significance Analysis for Approximate Computing (SSA-AC) to analyze the target application program and guide the designers to identify parts of the program to which approximation can or cannot be applied. SSA-AC statically analyzes the significance of variables in the precise version of the program and thus needs no trial-and-error evaluation or specific test data. Experimental results show that SSA-AC can successfully extract the significance ranking of inputs/variables to be approximated in much shorter time than existing statistical works that are inevitably data dependent.

The effect of CeCl3 inhibitor on the localized corrosion of stainless steel in chloride solutions

AbstractStainless steels have been used extensively in many sectors such as medical and household appliances as well as construction. This has been primarily due to their high resistance to corrosion attacks, reasonable cost, and excellent mechanical properties. However, when placed in corrosive media stainless steel is susceptible to localized corrosion attacks, especially when placed in chloride solutions. The paper explores the issue of corrosion liability of austenitic (AISI 316) and duplex (UNS S32205) stainless steels in et aconditions of seawater environment as well as under the influence of an inhibitor in the same environmental conditions. The behavior of stainless steels was examined via electrochemical testing relying on DC and AC techniques, optical metallographic analysis, scanning electron microscopy, and X‐ray diffraction analysis. Duplex stainless steel showed better resistance to localized corrosion but a higher tendency toward general corrosion in all examined solutions. Cerium chloride in a chloride solution showed inhibiting properties for both the AISI 316 and the UNS S32205.

Electrochemical Comparison of SAN/PANI/FLG and ZnO/GO Coated Cast Iron Subject to Corrosive Environments.

ZnO/GO (Graphene Oxide) and SAN (Styrene Acrylonitrile)/PANI (Polyaniline)/FLG (Few Layers Graphene) nanocomposite coatings were produced by solution casting and sol-gel methods, respectively, to enhance corrosion resistance of ferrous based materials. Corrosive seawater and ‘produced crude oil water’ environments were selected as electrolytes for this study. Impedance and coating capacitance values obtained from Electrochemical Impedance Spectroscopy (EIS) Alternating Current (AC technique) showed enhanced corrosion resistance of nanocomposites coatings in the corrosive environments. Tafel scan Direct Current (DC technique) was used to find the corrosion rate of nanocomposite coating. SAN/PANI/FLG coating reduced the corrosion of bare metal up to 90% in seawater whereas ZnO/GO suppressed the corrosion up to 75% having the impedance value of 100 Ω. In produced water of crude oil, SAN/PANI/FLG reduced the corrosion up to 95% while ZnO/GO suppressed the corrosion up to 10%. Hybrid composites of SAN/PANI/FLG coatings have demonstrated better performances compared to ZnO/GO in the corrosive environments under investigation. This study provides fabrication of state-of-the-art novel anti corrosive nanocomposite coatings for a wide range of industrial applications. Reduced corrosion will result in increased service lifetime, durability and reliability of components and system and will in turn lead to significant cost savings.

Effect of metal oxide nanoparticles XO (X=Ni, Cu, Mn) on the physical properties of hybrid organic/inorganic nanocomposites

Hybrid organic/inorganic nanocomposites were synthesized by sol-gel technique after the incorporation of nickel oxide (NiO), copper oxide (CuO) and manganese oxide (MnO) nanoparticles (NPs) in carbon matrix based on pyrogallol and formaldehyde (PF) using picric acid as catalyst. After a drying step, the samples were heated for 2 h at different pyrolysis temperatures between 600 and 1000 °C in tubular furnace under open nitrogen atmosphere. The obtained samples have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), direct current (dc) and alternating current (ac) techniques in the measurement temperature range between 80 and 300 K. The XRD spectra show that PF matrix is amorphous even after thermal treatment at 1000 °C. On the other hand, the different nanocomposites PF/NiO, PF/CuO and PF/MnO are crystallized with the appearance of the graphite structure at high pyrolysis temperature. The temperature dependence conductivities can be explained by Godet-Variable Range Hopping (3D-GVRH) conduction model in all samples with the presence of an exponential distribution of localized states. The ac investigation shows the dominance of semiconductor or metallic behaviour, depending on the metal oxide NPs incorporated and the pyrolysis temperature.

Electrochemical Noise of Electrophoretic Coatings with Nanoparticles TiO2 and ZnO

INTRODUCTION Organic coatings based on nanotechnology have been of great interest in recent years, thanks to the increase in performance with significantly optimized or improved properties in various aspects such as those that block UV rays, anti-scratch coatings, anti-abrasion, anticorrosive, superhydrophobic and coatings of barrier. Previous studies have found that there are nanoparticles that provide qualities to the coating such as the incorporation of nanoparticles such as Al2O3, SiO2, ZrO2 and TiO2 in a transparent layer matrix could significantly improve the scratch resistance as suggested by Bautista, et. al. Despite the efforts that have been made by incorporating some type of nanoparticles in organic coatings as mentioned above, this type of systems are prone to suffer corrosion damage in various environments. This type of damage can be analyzed by laboratory-level electrochemical techniques, including Electrochemical Noise, which is a non-destructive technique, and which reflects the individual sum of the random events of the potential and / or current fluctuations of a material subject to corrosion conditions; and the value of the root mean square (RMS) of the amplitude of these events or standard deviation has been shown to provide the fingerprint of the amount of dissolved metal, depending on the metal-environment combination. Another technique used for this type of systems is Electrochemical Impedance Spectroscopy, which, like EN is a non-destructive technique that indicates changes in the system before they are visible. For the specific case of coatings, it is possible to study the deterioration of these by the action of an electrolyte and the increase of the corrosion rate in the substrate, either by the deterioration of the coating or by the attack of the electrolyte. In recent years, the enormous potential of electrophoretic deposition (EPD) as a processing method for the realization of unique micro and nanostructures and combinations of novel materials has been recognized by the materials science community. Within this type of paintings is the so-called E-coat (cathodic) In this work we will analyze the transients observed in the time series of potential and current corresponding to the Electrochemical Noise and graphics of Electrochemical Impedance Spectroscopy measurements, of EPD coatings with and without the addition of TiO2 nanoparticles. EXPERIMENTAL METHODOLOGY Cathode Electrophoretic Coating (e-coat) The cathodic electrophoretic coating (e-coat) will be applied on steel sheets with a cathodic epoxy resin paint, previously preparing the surface with alkaline washing, pickling, phosphating and sealer. After the deposition of the paint, a curing will be carried out for the polymerization and evaporation of paint solvents. Coatings will be made without and with the addition of TiO2 nanoparticles to evaluate the effect of these. The bath temperature was set at 36 ° C and the deposition time was 2:50 min with an applied voltage of 140 V. Electrochemical tests. AC and DC techniques will be used, and corrosion monitoring will be carried out for various periods. The electrochemical parameters derived from each of the techniques will be obtained. The solutions used for the electrochemical tests will be prepared before carrying out these and will be 3.5% sodium chloride (NaCl) and distilled water. A cell will be used to evaluate paintings. The electrochemical techniques used will be: Electrochemical Noise (ASTM G199) and Electrochemical Impedance Spectroscopy (ASTM G106). using a potentiostat / galvanostat brand Solartron 1287A with 1285 interface. RESULTS The Bode diagrams obtained from the electrochemical impedance tests for the coatings, exposed in a 3.5%wt NaCl solution. It can be seen that the coating with the addition of TiO2 nanoparticles presents a higher impedance at high and low frequencies. In addition, in the system that does not have the addition of nanoparticles, noise is observed at frequencies between 102 and 103 Hz, which indicates, possibly, an activity between the electrolyte and the pigments contained in the paint. Impedance values between 105 and 106 Ω-cm2 are presented. CONCLUSIONS Laboratory coatings were prepared without and with the addition of TiO2 nanoparticles. The coatings with the addition of nanoparticles presented a visual finish with greater aesthetics. The electrochemical impedance tests indicate that the coating with addition of TiO2 nanoparticles, provides a slight increase in the resistance against corrosion, presenting impedance values between 105 and 106 Ω-cm2.

Corrosion Resistance Evaluation of Ni-Al \ YSZ Composite Coatings by An Electrochemical Investigation

The composite coating is used to protect carbon steel pipeline from corrosion by Surfacemodification using thermal spraying technique to enhance the corrosion resistance of carbonsteel. In this study the influence of sour hydrocarbon on carbon steel was investigated onsamples taken from Alloys with (API 5L) that used for oil transport pipe lines in North OilCompany in Kirkuk fields and specifically from well (No. K-130) which the oil sample wasbrought as well. The cermets coating (Ni-Al /ZrO2-8Y2O3) were prepared in different mixingratios of Yttria-Stabilized Zirconia (YSZ) with Ni-Al as a self-bonding. Several mixing ratios ofthe binder (Ni-Al) were used to prepare the cermets for thermal spraying coating namely 15%and 50%. In order to study the effect of roughness on the binding of the cermets and hence thecorrosion behavior of the carbon steel another specimen was mechanically abraded to a surfacefinish 800 grit by SiC paper and the cermets mixing ratio (50% YSZ+ 50% Ni-Al) .The thermalspraying gun was located in an angle of 90º in front of the carbon steel specimen and the distancebetween them was 16 cm. The corrosion behavior of the modified surface in comparison withuntreated one was investigated by electrochemical techniques. Two electrochemical techniques(DC and AC techniques) were used. The AC technique was potentiodynamic cyclic polarizationusing Solatron 1287, USA) potentiostat/galvanostate. The EIS measurements for all coatedspecimens show enhancement in the impedance parameters (total impedance |Z|, polarizationresistance (Rp) and the capacitance (C)) comparing to the uncoated one. The cermets thermallysprayed coating show improvement in the corrosion parameters.

Electro-analytical method for the quantities evaluation of the silicon solar cell by DC and AC characterization technique

Mono and Poly- crystalline silicon (Si) based solar cell has proven to be the most efficient and matured technology till date. The present work reports an exact electro-analytical method for the evaluation of different performance parameters in the current voltage response of the Si solar cell by DC and AC characterization technique. The extracted solar cell parameters from DC and AC techniques were compared with each other under the proper limiting conditions of low and high forward bias. The DC and AC characterization are used to determine the bias dependence of ideality factor and series resistance, respectively. The current-voltage (J-V) characteristics is combined with the impedance spectroscopy (IS) measurements to reveal the various interfacial, resistive and recombination analysis of the silicon solar cell. Herein the experimentally obtained J-V characteristics under the illumination condition have been reconstructed by individually extracted parameters from DC and AC measurements. Moreover, the present mechanistic provides a simple tool for analysing the commercial Si solar cell with a wide applicability for other solar cells.

Electrochemical Characterization of Low-Temperature Molten Mixture Systems Suitable as an Innovation in Aluminum Technology

The electrical conductivity has been measured and described for low-temperature NaF-KF-AlF3 mixtures by the electrochemical impedance spectroscopy. The temperature dependence was investigated in the range from the temperature of primary crystallization to about (80–100)°C overheat, i.e. from 655°C to 875°C. The electrolytes with the molar ratios in the range from 1.2 to 1.5 (with a step of 0.1) have been investigated. The electrical conductivity has been measured for four different concentrations of NaF (50, 40, 20 and 10%) in the mixture NaF-KF-AlF3 at all molar ratios. The electrical conductivity was measured using a tube–type cell with stationary electrodes applying AC–techniques with a sine wave signal in the high frequency range. The values of electrical conductivity decreased with lower MRs and with lower temperatures. Higher addition of NaF led to higher electrical conductivity. The concentration and temperature dependency of the electrical conductivity was described by the regression equation. The equation is valid throughout the studied concentration and temperature range.

Fluctuation-induced conductivity in melt-textured Pr-doped YBa2Cu3O7-δ composite superconductor

ABSTRACTIn this study, the effects of thermal fluctuations on the electrical conductivity in melt-textured YBa2Cu3O7-δ, Y0.95Pr0.05Ba2Cu3O7-δ and (YBa2Cu3O7-δ)0.95–(PrBa2Cu3O7-δ)0.05 composite superconductor were considered. The composite superconductor samples were prepared through the top seeding method using melt-textured NdBa2Cu3O7-d seeds. The resistivity measurements were performed with a low-frequency, low-current AC technique in order to extract the temperature derivative and analyze the influence of the praseodymium ion on the normal superconductor transition and consequently on the fluctuation regimes. The results show that the resistive transition is a two-step process. In the normal phase, above the critical temperature, Gaussian and critical fluctuation regimes were identified, while below the critical temperature, in the regime near the approach to the zero-resistance state, the fluctuation conductivity diverges as expected in a paracoherent-coherent transition.

Anticorrosion performance of three newly synthesized isatin derivatives on carbon steel in hydrochloric acid pickling environment: Electrochemical, surface and theoretical studies

In this work, three new isatin derivatives (5-BEI, 5-HEI and 5-FEI) were synthesized and their inhibition effect on carbon steel in hydrochloric acid medium has been evaluated. The detailed study of 5-BEI is given using gravimetric measurements and electrochemical methods (DC and AC techniques). The results showed that this new isatin is an efficient corrosion inhibitor for carbon steel in 1M HCl and an inhibition efficiency of 95.2% was exhibited by 5-BEI at 1mM concentration of 5-BEI after 6h of immersion at 303K. Polarization curves suggested that the 5-BEI acted as mixed type inhibitor. Electrochemical impedance spectroscopy showed that increase inhibitor (5-BEI, 5-HEI and 5-FEI) concentration leads to an increase in the values of the charge transfer resistance. Adsorption of 5-BEI, 5-HEI and 5-FEI molecules on the steel surface obeyed Langmuir adsorption isotherm model. X-Ray Photoelectron Spectroscopy (XPS) analyses revealed that the corrosion inhibition mechanism of 5-BEI is mainly controlled by a chemisorption process. The comparative study of inhibitive performance of the three isatin derivatives (5-BEI, 5-HEI and 5-FEI) using Density functional theory (DFT) calculations of orbital energies and reactivity indices suggested that the trend of inhibition potentials of the compounds depend on the effect of substituent atoms (Br, F, and H) on the electron donating and/or accepting ability of the molecules. The trend of reactivity of the molecules was 5-BEI>5-FEI>5-HEI. Theoretical Monte Carlo simulation studies also corroborated experimental findings.

Comprehensive Interfacial Mechanisms of LiMnPO4-MWCNT Composite ratios in Acidic Aqueous Electrolyte

A comprehensive electrochemical characterization was performed for different compositions of LiMnPO4 electrodes with additions of multi-walled carbon nanotubes (MWCNTs). Electrochemical testing based on DC and AC techniques helped to perform a quantitative analysis to corroborate the influence of the activation processes at the interface and the overall performance of the cathodes. The step-control process for the composite/electrolyte interface is influenced by the MWCNTs content at different bias potentials. The threshold saturation of MWCNTs was determined experimentally by materials characterization, electrochemical techniques, and theoretically by probability-deterministic transmission line modeling (TLM). TLM was coupled with the LiMnPO4 particle size distribution and the electrode microstructural variability to quantify interfacial mechanisms.

Synthesis and Characterization of Mg-Based Coatings for Sacrificial Cathodic Protection of Mg Alloy AZ31B

Magnesium (Mg) alloys are becoming increasingly popular for weight reduction in the automotive industry due to their low density and nominal specific strength [1]. However, the deleterious intrinsic corrosion rates of Mg alloys have hindered their widespread application. To date, protection strategies for Mg alloys has consisted primarily of barrier coatings such as Rockhard™ and Tagnite™ which have not demonstrated the ability to protect bare Mg at scratches, cracks, and other defects [2] while conversion coatings have not been shown to survive harsh working conditions and do not provide sacrificial cathodic protection or inhibitor release [3]. The drawbacks of these coating strategies provide motivation for additional research. In addition, sacrificial cathodic protection of Mg alloys has not been widely studied and presents opportunities of high interest. Recent studies have shown that sacrificial cathodic protection of Mg and its alloys is possible and shows some promise albeit complicated by cathodic corrosion of Al rich phases and large local cathodic reaction rates [4]. However, an optimal sacrificial coating has not been produced to date. As such, the overall goal of this research is to design a tunable coating which acts as (1) a corrosion barrier, (2) provides sacrificial cathodic protection, and (3) functions as a reservoir for ionic inhibitor release. Such a coating has been designed recently for aluminum alloy AA2024 using an amorphous Al-Co-Ce alloy [5]. The present work aims to study sacrificial Mg-based coatings produced by pulsed laser deposition (PLD) tuned for the Mg alloy AZ31B-H24 (Mg-3Al-1Zn). Binary and ternary coatings using rare earth elements known to decrease the OCP of Mg [6] and exhibit some ability for inhibitor release (RE = La, Gd, Y) as well as elements such as Ge and Sn [7] which poison cathodic kinetics, will be explored. Preliminary results of a Mg88Gd9Y3 based coating on AZ31B revealed a two-phase microstructure consisting of an extended solid solution Mg-rich matrix with a grain size on the order of 100 nm as well as a small fraction of Gd-Y rich particles < 1 μm in diameter. Immersion testing of PLD coated AZ31B in 0.6 M NaCl revealed an open circuit potential of -1.58 VSCE which is mildly cathodic to uncoated AZ31B (-1.56 VSCE) after a 24-hour exposure. In addition, the coating was observed to dissolve preferentially on an AZ31B surface demonstrating ability as a sacrificial anodic coating. Future testing will systematically explore the effects of alloying element concentration on the corrosion behavior of PLD coated AZ31B utilizing both AC and DC electrochemical techniques. Such an understanding will provide a framework to optimize a sacrificial cathodic coating for AZ31 based on critical factors such as open circuit potential, corrosion rate, galvanic couple potential, and galvanic couple current. Acknowledgments: This project is funded by the US Air Force Academy under agreement number FA7000-13-2-0020 as part of Corrosion University Pilot Program under the direction of Mr. Daniel Dunmire and by the National Science Foundation under NSF DMR#1309999 as well as the Army Research Office under agreement number W911NF-14-2-0005 with project manager Joe Labukas. The U.S. Government is authorized to reproduce and distribute reprints for government purposes notwithstanding any copyright notation thereon. The views and conclusions contained are those of the authors and should not be interpreted as necessarily representing the official policies or endorsement of the US Air Force Academy or the US Government.

Comparison of activation energies for the electrical conductivity of silicate glasses obtained by dc and ac techniques

The electrical conductivity of glasses with composition (mol%) 22Na2O·8CaO·65SiO2·5MO2 (M=Si, Ti, Ge, Zr, Sn, Ce) was evaluated by two different experimental methods: low-voltage ac impedance and high-voltage dc resistivity. The ac measurements were carried out by the traditional impedance spectroscopy between 90 and 415°C. In the dc method, a steady-state electric field of about 1MV/m was applied during 5s at temperatures between 100 and 210°C, and the onset current, Io, was measured. Activation energies between 0.71 and 0.81eV were obtained. The differences between the values obtained by the dc and the ac methods are within experimental errors. The high electric field does not influence the concentration nor the mobility of the charge carriers for these experimental conditions and glass compositions. The dc method applied showed to be a suitable alternative to determine the temperature dependence of the electric conductivity of glasses to further calculation of the activation energy.

Electronic and Ionic Conductivities of LiNi1/3Mn1/3Co1/3O2-Li3PS4 Positive Composite Electrodes for All-Solid-State Lithium Batteries

Electronic and ionic conductivities of positive composite electrodes composed of LiNi1/3Mn1/3Co1/3O2 and Li3PS4 were measured by both DC and AC techniques. Two cell configurations of (a) electron-blocking cells and (b) ion-blocking cells were applied for the measurements. The conductivities determined by the DC technique showed a good agreement with those measured by the AC technique, which suggests that both the DC and AC techniques are useful for the measurements of the electronic and ionic conductivities. The electronic conductivities for the composite electrodes at the state of charge (SOC) 0% were lower than the ionic conductivities. The electronic conductivities drastically increased at SOC 50% and became higher than or equal to the ionic conductivities. Cell capacities were evaluated based on the electronic and ionic conductivities. At a high current density of 1.3 mA cm-2, cell capacities seemed to be associated with the ionic conductivities of the composite electrodes.

The Kinetic Parameters of the Oxygen Evolution Reaction (OER) Calculated on Inactive Anodes via EIS Transfer Functions: •OH Formation

The electrocatalytic behavior of “inactive” (Boron Doped Diamond (BDD), SnO2-Sb and PbO2) anodes toward the oxygen evolution reaction (OER) is evaluated using dc and ac techniques, under controlled experimental conditions (e.g. air bubbling, ohmic drop correction). Tafel slopes estimated from anodic polarization curves for all catalysts are located above 100 mV dec−1, suggesting that the rate-controlling step is similar for these materials at determined overpotentials. In agreement with the literature, it could be associated with the •OH generation since “active catalysts” displays slopes below 80 mV dec−1. A transfer function model is derived to account for the kinetic parameters of the OER mechanism for each anode, throughout its fitting to experimental electrochemical impedance spectroscopy (EIS) spectra. The model considers the kinetics of each elementary reaction and the material balances for the rates of formation of the adsorbates (H2Oads, •OHads, •Oads, •OOHads, and O2ads) involved in the OER. It is found that the rate-controlling step on SnO2-Sb (≤2.14 V), PbO2 (≤1.74 V) and BDD (2.54–2.71 V) is associated with the •OH formation, while this control is only modified when the potential becomes more positive for the oxide catalysts, thus, being determined by the production of adsorbed oxygen O2ads which on its turn promotes the O2 evolution. On the other hand, the rate-control step remains similar for BDD over the entire analyzed potential range, standing out its unique properties as inactive catalyst of the OER.

KEPERCAYAAN SEBAGAI MEDIASI HUBUNGAN CORPORATE IMAGE TERHADAP LOYALITAS PELANGGAN MOBIL LOW MPV

The program's cost environmentally friendly cars or Low MPV (LCGC) issued by the Indonesian government to bring the impact of the availability of consumer choices Indonesia to buy a car at a bargain price. The challenge is whether consumers have confidence that the car MPV although low cost but still quality. Nearly all car manufacturers to get the car with this type so that competition in the automotive business has become very competitive. This study aims to determine causality corporate image to build customer trust and customer loyalty Low MPV car. The study was conducted on customers of Toyota cars, with the number of respondents 150 , using ac cidental sampling and technique using path analysis. The results that the corporate image has a direct influence on the increase in customer loyalty, as well as striving indirectly through increased customer confidence LCGC Toyota. Manufacturer Toyota has the advantage of the corporate image of the customer against Toyota is high, so the products LCGC Toyota produced can be accepted by consumers for consumers / customers have a loyalty to Toyota, meaning that the high corporate image car customers LCGC Toyota lead to customer loyalty. Another result of this study that the corporate image is also able to increase customer confidence LCGC Toyota subsequent impact on improving customer loyalty, meaning that belief becomes a mediation of the causal relationship of corporate image on customer loyalty.