Electrochemical Impedance Techniques Research Articles

Effect of Acrylic Resin on the Protection Performance of Epoxy Coating for Magnesium Alloy

The low toughness of epoxy resin can influence its shielding performance against a corrosive medium and strength of adhesion to metal surfaces. Extensive efforts have been made to modify epoxy resin. In this research, acrylic resin was synthesized by the solution method, and 1 wt.%, 2.5 wt.%, and 5 wt.% were added to epoxy resin (E44 brand) to prepare coatings on the surface of AZ31B magnesium alloy. The effects of acrylic resin on the mechanical and protective properties of epoxy coatings were investigated via experiments measuring impact resistance, flexibility, and adhesion as well as the electrochemical impedance technique. Compared with the pure epoxy coating, the adhesion between the coating and the substrate increases by 1.37 MPa after the addition of 2.5 wt.% acrylic resin. Meanwhile, the pencil hardness has a slight change from 5B to 6B, and the flexibility significantly improves. Therefore, the epoxy coating exhibits enhanced anticorrosive properties after the addition of 2.5 wt.% acrylic resin.

“Exploring the Inhibitory Potential of Acetoxime-Zinc Chloride Adduct in Saline Environments for Mild Steel Corrosion Protection”

ABSTRACT In this work, acetoxime, zinc chloride and acetoxime adduct of zinc chloride, [ZnCl2.2{HON=C(CH3)2}] (ZA) were investigated as corrosion inhibitor's in 3.5%NaCl solution on mild steel. The electrochemical analysis was carried out using polarization measurements and electrochemical impedance technique and surface analysis was done by Scanning electron microscope coupled with Energy-dispersive X-ray spectroscopy. Using surface analysis and electrochemical data it was concluded that an inhibition synergy was developed when ZA was taken instead of acetoxime or zinc chloride alone in solution phase. Scanning electron microscope methods were used to examine the samples surface in the presence of inhibited solutions. The efficiency of inhibition increases with the increasing concentration and attained the values of 97.18% for the 3mM concentration of ZA.

Facile Green Synthesis of α-Bismuth Oxide Nanoparticles: Its Photocatalytic and Electrochemical Sensing of Glucose and Uric Acid in an Acidic Medium

The nanocrystalline bismuth oxide (Bi2O3) was produced utilizing a green combustion process with Mexican Mint gel as the fuel. The powder X-ray diffraction (PXRD) method proved the nanocrystalline nature and Bi2O3 nanoparticles (BONPs) in α phase and the average crystalline size of BONPs nanoparticles has been found to be 60 nm. The spherical-shaped structure with bright dot-like spots in the center of the selected area diffraction (SAED) is confirmed by the scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDAX) in conjunction with the transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) demonstrating the crystalline behavior of green NPs. The Kubelka-Monk function was used to analyze diffuse reflectance spectra, and the results revealed that BONPs have a band gap of 3.07 eV. When utilized to evaluate the photocatalytic capabilities of NPs, the direct green (DG) and fast orange red (F-OR) dyes were found to be activated at 618 and 503 nm, respectively. After 120 min of exposure to UV radiation, the DG and F-OR dyes’ photodegradation rate reduced its hue by up to 88.2% and 94%, respectively. Cyclic voltammetry (CV) and electrochemical impedance techniques in 0.1 N HCl were used to efficiently analyze the electrochemical behavior of the produced BONPs. A carbon paste electrode that had been enhanced with BONPs was used to detect the glucose and uric acid in a 0.1 N HCl solution. The results of the cyclic voltammetry point to the excellent electrochemical qualities of BONPs. Bi2O3 electrode material was found to have a proton diffusion coefficient of 1.039 × 10−5 cm2s−1. BONP exhibits significant potential as an electrode material for sensing chemicals like glucose and uric acid, according to the electrochemical behavior.

Activated Carbon Electrodes for Supercapacitors from Purple Corncob (Zea maysL.).

Activated carbon-based supercapacitor electrodes synthesized from biomass or waste-derived biomass have recently attracted considerable attention because of their low cost, natural abundance, and power delivery performance. In this work, purple-corncob-based active carbons are prepared by KOH activation and subsequently evaluated as a composite electrode for supercapacitors using either an acidic or an alkali solution as the electrolyte. The synthesis of the material involves mixing the purple corncob powder with different concentrations of KOH (in the range of 5% to 30%) and a thermal treatment at 700 °C under an inert atmosphere. Physicochemical characterizations were performed using scanning electron microscopy, Raman spectroscopy, N2 physisorption analysis, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, while the electrochemical characteristics were determined using cyclic voltammetry, a galvanostatic charge/discharge curve, and electrochemical impedance techniques measured in a three- and two-electrode system. Composite electrodes activated with 10% KOH had a specific surface area of 728 m2 g-1, and high capacitances of 195 F g-1 at 0.5 A g-1 in 1 mol L-1 H2SO4 and 116 F g-1 at 0.5 A g-1 in 1 mol L-1 KOH were obtained. It also presented a 76% capacitance retention after 50 000 cycles. These properties depend significantly on the microporous area and micropore volume characteristics of the activated carbon. Overall, our results indicate that purple corncob has an interesting prospect as a carbon precursor material for supercapacitor electrodes.

Impedimetric transduction from a single-step thin film nanoporous aluminum oxide as a DNA sensing electrode

A two-step anodization process has been widely used to grow a perfectly arranged Anodic Aluminum Oxide (AAO) nanoporous with high regularity and circularity. However, this method requires more time and electricity cost since the second step anodization will be conducted more than a couple of hours up to 24 h to obtain a perfect hexagonally arranged AAO. Besides, the usage of toxic chromic acid to remove the rough surface after the first anodization is not recommended. To solve this issue, a single-step of anodization method to grow AAO at 15 °C in 0.3 M of oxalic acid at 40 V for 1 h has been proposed. In this study, the growth AAO thin film will be tested as a DNA biosensor electrode. Prior to that, instead of using toxic chemicals, couple of drops of phosphoric acid solutions were used to treat the rough, uneven surfaces by promoting hydroxyl groups while at the same time widening and revealed the underneath pores. The AAO thin film is ready for the next step of surface modification without a second anodization step. Surface chemical functionalization using 3-aminopropyl-triethoxysilane (APTES) and glutaraldehyde is performed to immobilize the aminated-ssDNA probe on the surface. The electrochemical impedance technique is employed to monitor the changes in each layer of surface modifications. The charged transfer resistance (Rct) values are linearly increased with each new additional layer on the AAO surfaces during each step of surface modification and with the increase in ssDNA complementary target concentrations (10 fM-10 μM). From the performance test, the single-step AAO thin film electrode has shown great results in functioning as a DNA biosensor through a selectivity test. It has the capability to differentiate the complementary sequences from the single mismatched target with 3-fold.

Bismuth oxide and nitrogen-doped reduced graphene oxide co-modified glassy carbon electrode to perform sensitive electrochemical sensing and determination of chrysin in pharmaceutical capsules

A bismuth oxide- nitrogen doped reduced graphene oxide/glassy carbon electrode (Bi2O3-NRGO/GCE) was prepared for the detection of the flavonoid drug chrysin in pharmaceutical capsules, for the first time. Bi2O3 nanosheets synthesized by a hydrothermal method, were ultrasonically mixed with NRGO, and a simple and efficient Bi2O3-NRGO/GCE composite was prepared. The composites were characterized by various methods. Cyclic voltammetry and electrochemical impedance techniques were used to study the electrochemical sensing performance of the composites-modified electrode surface. The electrochemical performance and optimal detection conditions of chrysin on Bi2O3-NRGO/GCE were investigated by differential pulse voltammetry (DPV). The oxidation peak current of chrysin has a linear relationship with its concentration, in the range of 0.01–10 μM, with a detection limit of 2.0 nM. Bi2O3-NRGO/GCE also has good selectivity for chrysin, which is not interfered with by common inorganic salts and common organic substances, or by structurally similar substances. The composite electrode also has good repeatability, reproducibility and stability. It shows that utilizing Bi2O3 and NRGO binary complexes modified electrodes for ultrasensitive chrysin sensing is a simple and convenient detection method, with promising applicability in the development of pharmaceutical component sensing technology.

Application of the Electrochemical Impedance Technique for the Study and Evaluation of Corrosion in HSLA X65 Steels in a Simulated Environment of Sour Gas H2S

The main sources for primary energy generation are oil and natural gas, high demand requires the use of pipelines that guarantee transportation in large quantities. Increased use of pipelines, for which it was necessary to develop high-strength steel tubes for long-distance transportation. High-strength, low-alloy steels (HSLA) are a great alternative for transportation, they mechanically resist high pressures and the reduction in manufacturing and maintenance costs is important for large industries. However, in sour gas (H2S) media it may be susceptible to corrosion, therefore studies to assess corrosion resistance are important. The present investigation evaluated the HSLA X65 steel in sour gas media through electrochemical and microstructural characterization techniques, showing its resistance to corrosion in aggressive media and showing that it can be used reliably for the transportation of oil and natural gas.

Enhanced corrosion inhibition effect of sodium tartrate on copper in potable water

In this study we have reported sodium tartrate (ST) and Zn2+ as the potential mixed corrosion inhibitors for copper corrosion in drinking water, by using electrochemical impedance and polarization techniques. The results of potentio-dynamic polarization indicated that sodium tartrate could be used as mixed type inhibitor with Zn2+. ST was found to be 92% effective for slowing down both the anodic and cathodic reaction rates. It was additionally found that ST could coat the surface of copper to prevent it from conducting electricity. As the inhibitor concentration increased, the stability of the formed protective layer was also improved. The results obtained from studies like SEM, EDAX, AFM, and water contact angle clearly indicated the development of a barrier by inducing the lotus effect on copper surface. The water contact angle measurement results suggested that the coating formed in the presence of inhibitor was superhydrophobic, and the surface was homogeneous.

MoS2 blended MWCNT hybrid nanocomposites and its enhanced super capacitive features

The present work addresses a simple and sensitive approach to synthesize a 2D bare MoS2 and graphene analog MoS2/MWCNT nanocomposites as an effective electrode material for high-performance supercapacitors. The MoS2/MWCNT nanocomposites were prepared via simple hydrothermal treatment. The structural, functional, and morphological analysis were accessed through XRD, HRTEM, FESEM, FTIR, and RAMAN Spectroscopy augmenting the successful formation of MoS2/MWCNT nanocomposites. The structural analysis confirms the formation of the hexagonal phase. The morphological analysis possesses the nano-sphere-like structure which is made up of crumpled nanosheets. The chemical bonding and the location of Mo–S and CC bands were confirmed at 428 and 1651 C m-1 respectively. Detailed electrochemical analysis through cyclic voltammetric study, Galvanostatic Charge/discharge and electrochemical impedance techniques shows that as prepared m-M10 sample exhibits excellent super capacitive performances when compared to other samples. This electrode obtained a maximum specific capacitance of 848 F g-1 with a current density 1 A g-1. This material retains 82% of its initial capacitance after 5000 repeated charge-discharge cycles. It exhibits very less charge transfer resistance 0.2Ω and lesser than other electrodes.

Experimental investigation of anti-corrosive behaviour of Beta vulgaris: A green approach

The loss of metals due to corrosion can be prevented using green inhibitors. Using natural and eco-friendly plant products is futuristic, preventing the environment from toxic and harmful chemicals. The present study aimed to investigate whole beetroot (BR, Beta vulgaris) for its anti-corrosion behaviour by galvanostatic polarization and electrochemical impedance techniques at a temperature between 298 K- 328 K. The temperature study would help in proposing BR's adsorption mechanism on metal surfaces. The maximum inhibition efficiency of 94% at 298 K for 5% BR was observed, whereas a minimum of 75% was obtained for 1% BR at 328 K. It was found to be a mixed-type inhibitor that followed Langmuir isotherm. From thermodynamic studies, ΔGoads was found to be -13.64 kJ/mol, which revealed that BR adsorbed physically on the surface of mild steel. Rct values increased while Cdl values decreased on exposure of metal surface with BR extract. The scanning electron micrographs (SEM) and atomic force micrographs (AFM) witnessed the formation of a protective layer on the mild steel surface, which served as a barrier between the metal and corrosive medium. The present study provides a remedy for the financial and structural losses due to metal corrosion in an acidic medium.

Combined electrochemical, DFT/MD-simulation and hybrid machine learning based on ANN-ANFIS models for prediction of doxorubicin drug as corrosion inhibitor for mild steel in 0.5 M H2SO4 solution

In this work, Doxorubicin drug was used as mild steel corrosion inhibitor in 0.5 M H2SO4 solution. Herein, standard techniques like gravimetric, electrochemical measurement, density functional theory via DFT/ molecular dynamic simulation (MDS), Scanning electron microscopic (SEM), were used for proper evaluation of Doxorubicin drug as anticorrosive agent. According to the experimental findings, Doxorubicin drug significantly inhibits mild steel corrosion, and its effectiveness increases with an increase in the drug concentration. Maximum inhibition efficiency at 100 ppm was 93.3 %, 91.3 % and 96.8 % for electrochemical impedance (EIS), polarization test (PDP) and gravimetric techniques respectively. The electrochemical study indicates that Doxorubicin is a mixed-type inhibitor. Close scrutiny of the corroded and inhibited metals evidenced that Doxorubicin drug produced a better and more uniform coating on the surface of mild steel. The molecular structure of the drug and its contribution to the inhibition mechanism was further understood using simulations based on density functional theory (DFT) and molecular dynamics simulation (MDS). In addition, artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) were used to predict and model the interactive effects affecting the response. Also, statistical parameters like coefficient of determination (R2), root mean square error (RMSE), mean absolute percentage error (MAPE), and mean absolute deviation (MAD) were used to assess the models' performance. The results demonstrate that the FCM-clustered ANFIS model with 15 clusters perform better than ANN model with RMSE, MAD, MAPE, and R2values of 0.978, 0.642, 4.823, and 0.9925 at the testing phase, and 0.6435, 0.4248, 2.8151, and 0.9998 at the training phase respectively. The best prediction was made using complete FCM-ANFIS model, which had accuracy of 98.4 %. Hence, a robust system prediction can be achieved via ANN and ANFIS algorithms to predict corrosion inhibition of mild steel in acidic environment using drug based corrosion inhibitors.

Development and characterization of DGEBA-APTES-ZrO2 nanocomposite coatings for anti-corrosion and anti-fouling

Tetraethylenetetramine (TETA), 3-aminopropylethoxysilane-treated ZrO2 nanoparticles, and diglycidyl ethers of bisphenol-A (DGEBA) were used to create an epoxy nanocomposite (DGEBA-APTES-ZrO2). The newly synthesized APTES-ZrO2 was evaluated using FTIR, XRD, SEM, AFM, TEM and elemental analysis for structural and compositional analysis. Due to its resilience in acidic, basic and saline conditions, mild steel is crucial in sectors like shipbuilding and the automobile industry. ZrO2 nanoparticles have excellent corrosion resistance. As a result, it is intended to prepare DGEBA-APTES-ZrO2 for a barrier layer that prevents corrosion on mild steel surfaces. FTIR spectroscopy tests provided proof of DGEBA-APTES-ZrO2-coated mild steel’s ability to limit corrosion and microbiological growth. Using salt spray and an electrochemical impedance technique, corrosion inhibition was evaluated. On mild steel surfaces, DGEBA-APTES-ZrO2 nanohybrid coatings demonstrated excellent corrosion prevention and antifouling.

ZnO doped SnO2 nano flower decorated on graphene oxide/polypyrrole nanotubes for symmetric supercapacitor applications

Due to their high power density, lengthy cyclability, quick charge-discharge rates, and environmentally friendly design, supercapacitors are incredibly effective electrochemical energy storage devices. A lot of work has been progressed in this direction to increase the specific power and cyclic stability of supercapacitor mainly by using various metal oxides with 2D composites and high concentration electrolytes. But, there are some challenging issues like low energy density, high production cost, and short cyclic life. In this work, we aimed to resolve the low energy density and operating voltage of electrodes by selecting multiphase inorganic-organic material with a suitable concentration of electrolyte. To create such supercapacitor electrodes for high energy storage applications, ZnO doped SnO2 nanoflower decorated on graphene oxide/polypyrrole nanocomposite, which are novel materials with large specific surface area and cyclic stability were studied.The electrochemical study of the nanocomposite materials is done by studying the cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance (EIS) techniques. The supercapacitor device fabrication is processed using ZS/GP2 electrode, and the analysis of supercapacitor performance is also studied. As a result, ZS/GP2 nanocomposite showed a good capacitive behavior with a maximum specific capacitance of 392 F g−1 at 75 mV s−1 scan rate with significantly high specific energy and power density of 31.6 Wh kg−1 and 5177 W kg−1, respectively after the 27,000 consecutive charge-discharge (GCD) cycles at the current density of 0.25 A g−1. The results evidence that these hybrid materials are highly promising electrode materials for energy storage applications.

Polyoxometalate Archetype-Boosted Stability and Charge Storage of 2D Graphene Nanosheets

In this study, the potential of impregnation of phosphotungstic acid (PTA), a polyoxometalate in enhancing specific capacitance (C sp) and diminishing the well-known restacking phenomenon of graphene nanosheets was explored. Graphene nanosheets were prepared chemically from graphite powder through the formation of graphene oxide (GO) and then the subsequent reduction of GO to the reduced GO (rGO). Impregnation of PTA in rGO-PTA (rGP) composites was carried out by simply dispersing rGO and PTA derived from tungstic acid. Scanning electron microscopy, X-ray diffraction analysis, UV–vis reflectance spectroscopy, and Fourier-transform infrared spectroscopy were used to analyze the elemental composition, microstates, and morphology of the composites. The charge-storing capacity and stability of the prepared rGP composites casted on a graphite electrode were examined with cyclic voltammetric, chronopotentiometric, and electrochemical impedance techniques. The effect of ions on the charging capacity of the electrodes was verified using electrolytes with different ion sizes. About 100% enhancement of C sp of rGO with 87% capacitance retention for 2000 charging-discharging cycles was achieved by impregnating rGP composites with only 1% PTA.

Experimental and computational approaches of methoxy naphthylbithiophene derivatives and their use as corrosion protection for carbon steel in acidic medium

The inhibition efficiency and adsorption affinity were investigated for two novel compounds, namely: 6-methoxy-2-naphthyl-[2, 2’-bithiophene]-5-carboxamidine hydrochloride salt (MA-1440) and 5'-(4-chlorophenyl)-2, 2’-bifuran-5-carboxamidine hydrochloride salt (MA-1456). The inhibition study was conducted on carbon steel surface in 1.0 M HCl with different inhibitor doses and different temperature levels, to investigate the optimum dose and preferable temperature. The performed investigation included chemical, electrochemical, instrumental, and quantum computation techniques. A chemical technique was accomplished by using weight-loss measurements. Different factors were studied using weight-loss measurements in order to reach the maximum inhibition efficiency. The adsorption study revealed that the examined inhibitors obey the Langmuir adsorption isotherm and are chemically adsorbed on the steel surface. The electrochemical measurements were accomplished through the electrochemical impedance (EIS) and potentiodynamic polarization (PDP) techniques. Based on the electrochemical measurements, the examined compounds were categorized as mixed inhibitors. The instrumental examination using different techniques namely: scanning electron microscope (SEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) confirmed that the considered inhibitors are excellently adsorbed over the carbon steel surface. The extent of the adsorption affinity of these compounds on the carbon steel surface was studied theoretically using quantum computations and Monte Carlo simulation. The theoretical investigation results of quantum chemistry were validated with those obtained by chemical and electrochemical methodologies. All investigations prove that, the tested compounds were adsorbed chemically on the steel surface and achieved maximum inhibition efficiency of, 94.69% and 90.85% for M-1440 and MA-1456, respectively, at the optimum concentration 30 times 10–6 mol L−1 and temperature 328 K.

Electrochemical sensor based on MOF derived LaFexNi(1-x)O3 using carbon spheres as the template for simultaneous determination of p-aminophenol and paracetamol

Using metal–organic frameworks (MOFs) as the precursor and carbon spheres as the template, LaFexNi(1-x)O3 (x = 1, 0.8, 0.6, 0.4, 0.2, 0) perovskite-type oxides were synthesized. The structure, morphology and valence state of as-prepared perovskite-type oxides were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, and X-ray photoelectron spectroscopy. Cyclic voltammetry and electrochemical impedance techniques were used to study the effect of Ni-doping ratios on the electrocatalytic performance of perovskite. The differential pulse voltammetry was used to measure the content of p-aminophenol (PAP) and paracetamol (PAT) through the LaFe0.6Ni0.4O3 modified glassy carbon electrode. The experiment shows that among LaFexNi(1-x)O3 (x = 1, 0.8, 0.6, 0.4, 0.2, 0) perovskite-type oxides, LaFe0.6Ni0.4O3 was best electrode material due to its low charge transfer resistance and high electrochemical active surface area. The linear ranges of PAP and PAT were both 1.0–100.0 μM under optimized conditions, while the detection limits were 0.111 and 0.162 μM (S/N = 3), respectively. The practicality of the suggested sensor was explored through the simultaneous detection of PAP and PAT in real samples, and satisfactory findings in acetaminophen pills were obtained.

Polyaniline-Supported Nickel Oxide Flower for Efficient Nitrite Electrochemical Detection in Water.

A modified electrode with conducting polymer (Polyaniline) and NiO nanoflowers was prepared to detect nitrite ions in drinking water. A simple method was used to prepare the NiO nanoflower (NiOnF). Several techniques characterized the as-prepared NiOnF to determine the chemical structure and surface morphology of the NiO, such as XRD, XPS, FT-IR, and TGA. The activity of the electrode toward nitrite sensing was investigated over a wide range of pH (i.e., 2 to 10). The amperometry method was used to determine the linear detection range and limit. Accordingly, the modified electrode GC/PANI/NiOnf showed a linear range of detection at 0.1-1 µM and 1-500 µM. At the same time, the limit of detection (LOD) was 9.7 and 64 nM for low and high concentrations, respectively. Furthermore, the kinetic characteristics of nitrite, such as diffusion and transport coefficients, were investigated in various media. Moreover, the charge transfer resistance was utilized for nitrite electrooxidation in different pH values by the electrochemical impedance technique (EIS). The anti-interfering criteria of the modified surfaces were utilized in the existence of many interfering cations in water (e.g., K+, Na+, Cu2+, Zn2+, Ba2+, Ca2+, Cr2+, Cd2+, Pd2+). A real sample of the Nile River was spiked with nitrite to study the activity of the electrode in a real case sample (response time ~4 s). The interaction between nitrite ions and NiO{100} surface was studied using DFT calculations as a function of adsorption energy.

Electrodeposition and characterization of polypyrrole films on stainless steel

This paper deals with synthesis of polypyrrole, by the potentiostatic Electrodeposition for supercapacitor application. Polypyrrole (PPY) films were deposited on stainless steel substrates by electro polymerization from pyrrole solutions containing dehydrated 5-sulfosalicylic acid (SSA) as an anionic additive and annealed at 50 °C, 70 °C, 100 °C and 200 °C. Morphology and structure of polypyrrole were studied using SEM,XRD and FTIR technique. Supercapacitive behaviour were studied using Cyclic Voltammetry and Electrochemical impedance technique. Cyclic Voltammetry shows maximum capacitance 62.87F/gm at 2 mV/s for an annealing temperature of 70 °C. In this paper effect of annealing temperature on supercapacitor behaviour of polypyrrole was studied.

Effect of Condensation Product on the Electrochemical Behaviour and Corrosion Resistance of Zn and Zn-Ni Deposits

Electrodeposition of Zn and Zn-Ni deposits were performed on steel substrates under various conditions from acid sulphate baths in presence of condensation product of 3, 4, 5-trimethoxybenzaldehyde and serine (TMBS). The electrochemical behavior of deposits was studied by polarization and electrochemical impedance techniques. The Zn-Ni-bright deposits obtained from the acid sulphate bath at 4 Adm-2 showed a lower corrosion current (Icorr) and a less negative corrosion potential (Ecorr) compared to Zn-dull, Zn-Ni-dull and Zn-bright deposits. The surface morphology and phase structure of the deposits was studied by Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis.

New oxygen ion conducting composite solid electrolytes Sm2(WO4)3-WO3

Composite materials Sm2(WO4)3-WO3 were prepared by the solid state method and their transport properties have been examined by the electrochemical impedance technique and conductivity measurements versus oxygen partial pressure. It was shown that heterogeneous doping of the oxygen ion conductor Sm2(WO4)3 with a semiconductor WO3 even at low concentration of WO3 (volume fraction f < 0.13) led to an increase in ionic conductivity of the composites by more than an order of magnitude. This effect is caused by formation of the non-autonomous interface phase Sm2W6O21 covering grain boundaries of Sm2(WO4)3. At high concentrations of WO3 (f > 0.13) the composite materials comprise biphasic mixture with mixed ionic-electronic conductivity. Dependences of the conductivity on temperature, WO3 concentration and oxygen partial pressure were described in terms of the brick-wall model (at f < 0.13) and the generalized mixing equation (at f > 0.13) and conductivity parameters of the O2− ion conducting interface phase were determined.