Electrochemical Impedance Method Research Articles

A "2-in-1" Bioanalytical System Based on Nanocomposite Conductive Polymers for Early Detection of Surface Water Pollution.

This work proposes an approach to the formation of receptor elements for the rapid diagnosis of the state of surface waters according to two indicators: the biochemical oxygen demand (BOD) index and toxicity. Associations among microorganisms based on the bacteria P. yeei and yeast S. cerevisiae, as well as associations of the yeasts O. polymorpha and B. adeninivorans, were formed to evaluate these indicators, respectively. The use of nanocomposite electrically conductive materials based on carbon nanotubes, biocompatible natural polymers-chitosan and bovine serum albumin cross-linked with ferrocenecarboxaldehyde, neutral red, safranin, and phenosafranin-has made it possible to expand the analytical capabilities of receptor systems. Redox polymers were studied by IR spectroscopy and Raman spectroscopy, the contents of electroactive components were determined by atomic absorption spectroscopy, and electrochemical properties were studied by electrochemical impedance and cyclic voltammetry methods. Based on the proposed kinetic approach to modeling individual stages of bioelectrochemical processes, the chitosan-neutral red/CNT composite was chosen to immobilize the yeast association between O. polymorpha (ks = 370 ± 20 L/g × s) and B. adeninivorans (320 ± 30 L/g × s), and a bovine serum albumin (BSA)-neutral composite was chosen to immobilize the association between the yeast S. cerevisiae (ks = 130 ± 10 L/g × s) and the bacteria P. yeei red/CNT (170 ± 30 L/g × s). After optimizing the composition of the receptor systems, it was shown that the use of nanocomposite materials together with associations among microorganisms makes it possible to determine BOD with high sensitivity (with a lower limit of 0.6 mg/dm3) and detect the presence of a wide range of toxicants of both organic and inorganic origin. Both receptor elements were tested on water samples, showing a high correlation between the results of biosensor analysis of BOD and toxicity and the results of standard analytical methods. The results obtained show broad prospects for creating sensitive and portable bioelectrochemical sensors for the early warning of environmentally hazardous situations based on associations among microorganisms and nanocomposite materials.

Highly sensitive determination of acyclovir using Ti3C2-CS-MWCNTs-COOH/GCE composite as a sensing platform

Acyclovir (Acyclovir, ACV) is an antiviral drug which, despite its favorable safety profile, can have systemic adverse effects, following improper use. This study prepared a clay-like two-dimensional transition metal carbide Ti3C2 by etching Ti3AlC2 with LiF and HCl. Carboxylated multi walled carbon nanotubes (Carboxylated multi-walled carbon nanotubes, MWCNTs-COOH) were combined with Ti3C2 using chitosan (Chitosan, CS) as solvent and ultrasonic treatment. The nanocomposite was then modified onto the surface of a glassy carbon electrode (Glassy carbon electrode, GCE) to develop an electrochemical sensor for the detection of ACV. The Ti3C2-CS-MWCNTs-COOH/GCE nanocomposite was characterized by X-ray diffractometry (X-ray diffractometry, XRD), scanning electron microscope (Scanning electron microscope，SEM), and cyclic voltammetry (Cyclic voltammetry，CV), as well as the electrochemical impedance method (Electrochemical impedance，EIS). The successful preparation of Ti3C2-CS-MWCNTs-COOH, and the good electrochemical performance of the electrode were verified. Linear scanning voltammetry (Linear scan voltammetry，LSV) was used to quantify the ACV. The linear range of the method is wider than other works (0.05 ∼ 20.0 and 20.0 ∼ 500.0 μM), with a low detection limit (0.088 μM). The sensor achieves sensitive detection of ACV and can be used for the analysis of ACV in pharmaceutical and urine dosage forms, with recoveries of 95.5∼97.6% and 95.6∼97.5%, respectively. For the first time, this sensor utilizes clay-like Ti3C2 with a larger specific surface area in combination with MWCNTs-COOH for ACV detection, which exhibits excellent immunity to interference, repeatability, reproducibility, and stability. This method provides a rapid and sensitive method for the determination of ACV, and lays foundations for developing miniaturized field rapid test detectors.

The Power of Lichens: New Eco‐Friendly Corrosion Inhibitors from Nature

AbstractThis research explores an environmentally friendly alternative: lichens, which produce natural compounds with antioxidant effects. This study focuses on the inhibition of corrosion by lichens, which has not been previously explored for this purpose. The anti‐corrosion potential of methanol extracts of Parmotrema hypoleucinum, Roccella phycopsis, and Xanthoria parietina was examined. The electrochemical impedance and weight loss methods were used to examine the corrosion inhibition process of mild steel XC48 in 1 M HCl by three lichen extracts.

Wide Response Range Photoelectrochemical UV Detector Based on Anodized TiO2-Nanotubes@Ti@quartz Structure.

Conventional sandwich structure photoelectrochemical UV detectors cannot detect UV light below 300 nm due to UV filtering problems. In this work, we propose to place the electron collector inside the active material, thus avoiding the effect of electrodes on light absorption. We obtained a TiO2-nanotubes@Ti@quartz photoanode structure by precise treatment of a commercial Ti mesh by anodic oxidation. The structure can absorb any light in the near-UV band and has superior stability to other metal electrodes. The final encapsulated photoelectrochemical UV detectors exhibit good switching characteristics with a response time below 100 ms. The mechanism of the oxidation conditions on the photovoltaic performance of the device was investigated by the electrochemical impedance method, and we obtained the optimal synthesis conditions. Response tests under continuous spectroscopy confirm that the response range of the device is extended from 300-400 nm to 240-400 nm. This idea of a built-in collector is an effective way to extend the response range of a photoelectrochemical detector.

An impedance labeling free electrochemical aptamer sensor based on tetrahedral DNA nanostructures for doxorubicin determination.

Based on the electrochemical impedance method, a marker-free biosensor with aptamer as a biometric element was developed for the determination of doxorubicin (DOX). By combining aptamer with rigid tetrahedral DNA nanostructures (TDNs) and fixing them on the surface of gold electrode (GE) as biometric elements, the density and directivity of surface nanoprobes improved, and DOX was captured with high sensitivity and specificity. DOX was captured by immobilized aptamers on the GE, which inhibited electron transfer between the GE and [Fe(CN)6]3-/4- in solution, resulting in a change in electrochemical impedance. When the DOX concentration was between 10.0 and 100.0nM, the aptasensor showed a linear relationship with charge transfer resistance, the relative standard deviation (RSD) ranged from 3.6 to 5.9%, and the detection limit (LOD) was 3.0nM. This technique offered a successful performance for the determination of the target analyte in serum samples with recovery in the range 97.0 to 99.6% and RSD ranged from 4.8 to 6.5%. This method displayed the advantages of fast response speed, good selectivity, and simple sensor structure and showed potential application in therapeutic drug monitoring.

Label-free flexible immunosensor based on nitrogen-doped graphene with titanium dioxide for the determination of depression marker dendritic cell nuclear protein-1

In this work, a label-free flexible immunosensor for selective and sensitive detection of dendritic cell nuclear protein-1 (DCNP1), a newly discovered potential marker of depression, was successfully constructed. At first, a highly conductive nanomaterial nitrogen-doped graphene with titanium dioxide (NG/TiO2) was prepared using a one-pot method, and it was used as an electrode modification material in the construction of immunosensors for the first time. NG/TiO2 was functionalized with 1-pyrene-butyric acid N-hydroxysuccinimide ester (PSE), and then the DCNP1 antibody could be better immobilized on the surface of the modified indium tin oxide-polyethylene terephthalate (ITO-PET). Then bovine serum albumin (BSA) was used to block non-specific active sites, and the immunosensor (BSA/anti-DCNP1-PSE/NG/TiO2/ITO-PET) can be obtained. The fabricated NG/TiO2 and the construction process of the immunosensor were characterized by scanning electron microscopy, infrared spectroscopy, cyclic voltammetry, and electrochemical impedance methods. Differential pulse voltammetry (DPV) was used to measure different concentrations of DCNP1 after optimizing the ratio of NG and TiO2, the modification amount of NG/TiO2, the ratio of NG/TiO2 to PSE, the concentration of anti-DCNP1 and its immobilization time, the concentration of BSA, and the incubation time of DCNP1. The constructed sensor had a wide linear range of 1 ∼ 104 pg mL−1, and a low detection limit of 0.45 pg mL−1 (S/N = 3). It had good reproducibility (RSD = 1.90 %), repeatability (RSD = 2.6 %), and selectivity. After storing it at 4 ℃ for 15 days, its performance decreased to 92.37 %. And it had been successfully used to determine DCNP1 in the brain homogenate of mice with depression induced by chronic unpredictable mild stress (CUMS), providing a possible method for the rapid and accurate determination of DCNP1.

Use of electrochemical impedance spectroscopy to assess the stability of the anion exchange membrane MA-41, modified by poly-N,N-diallylmorpholine bromide in overlimiting current modes

The paper presents the results of studying the electrochemical characteristics and long-term stability of MA-41 membranes on the surface of which poly-N,N-diallylmorpholinium bromide was applied. The deposition of a polyelectrolyte on the membrane surface leads to an increase in the limiting current from 0.8 to 1.1 mA/cm2. The comparison of the experimental and theoretically calculated values of the limiting current density allows us to conclude that the modification of the membrane surface by poly-N,N-diallylmorpholinium bromide does not lead to the formation of a continuous polyelectrolyte film on the surface, but its fixation occurs due to the sorption of macromolecules on the surface of the ion-exchanger particles. To quantify the rate of the water dissociation reaction at the membrane/solution interface, the method of electrochemical impedance was used, which makes it possible to compare the rate constants of the water dissociation reaction for different membranes, assuming that the reaction is described by the Gericher impedance. It is shown that modification of the MA-41 membrane surface leads to a decrease in the rate of the water dissociation reaction in the current range i = 1.5–4ilim by a factor of 2–6. The reduction in water dissociation reaction rate is attributed to the substitution of catalytically active secondary and tertiary amino groups in the surface layer of the pristine membrane by stable heterocyclic ammonium bases of poly-N,N-diallylmorpholinium. The study of the long-term stability of the resulting membrane showed that when the membrane is polarized with a current equal to twice the limiting current, the desorption of the modifier occurs within 25 h, and the properties of the membrane become close to those of the unmodified MA-41 membrane. It was shown that the electrochemical impedance method can be used as a very sensitive method for studying the long-term stability of ion-exchange membranes.

Superhydrophobicity of thermally annealed aluminum surfaces and its effect on corrosion resistance

Surface functionalization with chemical modification, i.e., low surface energy coating, is the most commonly used method to obtain hydrophobic/superhydrophobic surfaces. However, the fabrication procedures are complex or harmful to environment, and the factors affecting corrosion resistance of chemically modified surfaces are difficult to determine owing to the complicated anticorrosive mechanism. In this study, a simple and environment-friendly method was employed to prepare hydrophobic/superhydrophobic surfaces without chemical modification. The electrochemical impedance method was applied to measure the corrosion resistances, and the effective wetting area was used to elucidate the anticorrosive mechanism of hydrophobic surfaces. We found that the corrosion resistances of the fabricated Al samples were closely correlated with the surface wettability and further related to the effective wetting area at the solid–liquid interface. Consequently, a smaller effective wetting area results in a larger corrosion resistance and thus enhances the corrosion protection performance.

Development of Protonic Ceramic Fuel Cell Using BaZr0.2Yb0.8O3-δ as the Electrolyte

Protonic Ceramic Fuel Cells (PCFCs) are attracting attention as next-generation fuel cells that are expected to have lower operating temperatures and higher power generation efficiency than SOFCs. We have reported that BaZr0.8Yb0.2O3-δ does not chemically react with NiO used as a fuel electrode at 1475°C, which is the sintering temperature of the cell, and that the fuel cell can be fabricated by the tape casting method and the fuel electrode and electrolyte co-firing method used in industrial production processes for SOFCs and electronic components. This report describes issues that need to be resolved for the practical application of this cell.Fuel cells were fabricated by laminating green sheets prepared by the tape casting method and co-firing the electrolyte and fuel electrode together. For the air electrode, La0.6Sr0.4Co0.2Fe0.8O3-δ and La0.6Sr0.4CoO3-δ, which are widely used in SOFCs, and newly developed BaZr0.375Yb0.125Co0.5O3-δ were sintered at 900°C to 1000°C. The electrochemical performance of the planar cell was investigated at 600°C under the conditions of a humid fuel gas (i.e., 3% H2O and 97% H2) and humid air (i.e., 3% H2O, 20% O2 and 77% N2). The active area of the planar cell was 0.785 cm2.To evaluate the durability of each cell, continuous power generation tests were conducted at constant current. The durability test was conducted by generating power for 1000 hours at a constant current that resulted in a voltage of 0.85 V at the start of the test, and durability was evaluated by the rate of voltage drop per 1000 hours. As a result, the voltage reduction rate per 1000 hours for the cell using BaZr0.375Yb0.125Co0.5O3-δ as the air electrode was 7.3%/kh. The results clearly show that one of the most significant issues for practical use is the suppression of the rate of voltage drop. The resistance of the cell before and after the durability test were analyzed by electrochemical impedance method, and the ohmic resistance and electrode resistance increased. EPMA analysis of the cell cross section to investigate the cause of degradation revealed diffusion of Ni from the fuel electrode and Co from the air electrode in the electrolyte. Therefore, in order to further improve durability, there is a need to consider adding an anti-diffusion layer to prevent the diffusion of these elements and developing air electrode materials that do not contain Co.

OXYGEN-ION COMPOSITES MWO4-SiO2 (M – Sr, Ba)

Composite materials (1-f)SrWO4–fSiO2 and (1–f)BaWO4–fSiO2, where f is the volume fraction of the dispersed SiO2 additive, were prepared by the solid-phase method. The resulting composites were studied by XPA, TG-DSC, SEM-EDA. The electrical conductivity of the composites was measured by the electrochemical impedance method as a function of temperature, oxygen partial pressure in the gas phase, and composition. To estimate the contribution of ionic conductivity, the sum of ionic transfer numbers was measured by the EMF method. It has been shown that the addition of 20–25 vol % nano-SiO2 to low-conductivity oxygen-ion conductors SrWO4 and BaWO4 leads to an increase in the ionic conductivity of composites based on them by two orders of magnitude and by 12 times, respectively. The increase in conductivity in the systems under study is explained by the additional contribution of interfacial boundaries formed between the MeWO4 matrix and dispersoid nanoparticles. The mixing rule [1] was used to calculate the electrical conductivity of (1-f)SrWO4–fSiO2 and (1-f)BaWO4–fSiO2 composites depending on the SiO2 content. The calculated concentration dependences of the conductivity obtained are in satisfactory agreement with the experimental results.

Titanium dioxide (TiO2) and gel-polymer solar cells

This research focuses on the study of semiconductor-based solar cells utilizing titanium dioxide (TiO2) and gel-polymer electrolytes. The technology for preparing the electrolytes used in these solar cells has been developed, encompassing both liquid and gel polymer electrolyte compositions. The electrochemical impedance method is employed to determine important parameters such as diffusion coefficient, mobility, and charge carrier concentration in both liquid and gel-polymer electrolytes. Experimental results are compared with theoretical calculations utilizing the electrochemical impedance spectroscopy graph. Moreover, the photon-to-current conversion efficiency of the semiconductor-based solar cells is determined using the Incident Photon to Current Conversion Efficiency (IPCE) method, covering a wavelength range of 300 nm to 900 nm.

Non-Aqueous Zn-Ion Hybrid Supercapacitors: Acetonitrile vs Propylene Carbonate Based Electrolyte

The development of high efficiency energy storage systems is increasingly important as these systems enable utilize energy from renewable sources and reduce greenhouse gas evolution caused by fuel combustion technologies at the same time. Electrochemical characteristics of Zn-ion hybrid supercapacitor (ZIHS) cells based on 1 M acetonitrile and propylene carbonate electrolytes in zinc tetrafluoroborate (Zn(BF4)2), zinc di[bis(trifluoromethylsulfonyl)imide] (Zn(TFSI)2) and zinc trifluoromethanesulfonate (Zn(OTf)2) have been studied using cyclic voltammetry, constant current charge/discharge and electrochemical impedance methods. The Ragone plots have been calculated from constant power measurement data. Very high energy and power densities (80 Wh kg−1 and 21.2 kW kg−1) have been calculated for 1 M Zn(BF4)2/AN based Zn-ion hybrid supercapacitor. Some assembled ZIHSs had shown excellent cycling and energy stability over 20000 cycles.

Insight into the Origin of the Rapid Charging Ability of Graphene-Like Graphite as a Lithium-Ion Battery Anode Material Using Electrochemical Impedance Spectroscopy

Graphene-like graphite (GLG), a carbon material synthesized by heat treatment of graphite oxide, can be charged at a high rate without deposition of lithium metal even when the potential of the GLG anode is stepped below the Li deposition potential. However, the factors contributing to this outstanding rapid chargeability of GLG have been unclear until now. In this study, to clarify the factors, the charge-transfer resistance and diffusion resistance of GLG were quantitatively evaluated by the electrochemical impedance method using GLG thin films as model electrodes. The activation energy of lithium-ion transfer at the GLG/electrolyte interface was found to be almost the same as that reported for graphite, and it was clear that this process was as slow as that in graphite. On the other hand, the lithium-ion diffusion coefficient in GLG calculated from the Warburg impedance was several orders higher than that of graphite, which clearly shows that this contributed greatly to the fast-charging characteristics of GLG. In addition, in the comparison among GLGs with different structural parameters, the lithium-ion diffusion coefficient was higher for those with less oxygen content and more pores formed in the graphene layer inside the GLG. Therefore, it was concluded that a high diffusion coefficient was ascribed to the pores in the GLG, which enabled lithium-ion diffusion in the c-axis direction.

Sensitive electrochemical determination of riboflavin at simple and low-cost poly (valine) modified graphite paste electrode

• A modest, responsive, low-cost, and green electrochemically polymerised valine modified graphite paste electrode was developed. • FE-SEM, EI, and CV measurements are used for electrode materials characterisation. • Riboflavin electrochemical redox action was analysed using polymerised valine modified graphite paste electrode. • prepared electrochemical sensor provides a lower limit of detection with fine sensitivity and reproducibility. • The modified electrochemical sensor gives acceptable recoveries for riboflavin in medicinal sample. A sensitive electrochemical analysis of riboflavin (RFN) was done in 0.1 M phosphate buffer solution (PTBS) by constructing a modest and green electrochemically polymerised (EP) valine (VLN) modified graphite paste electrode (GPE). The electrochemical, morphological, resistive, and conductive characteristics of modified electrode (EP(VLN)MGPE) and bare graphite paste electrode (BGPE) surfaces were clarified through cyclic voltammetry (CV), field emission scanning electron microscopy (FE-SEM), and Electrochemical impedance (EI) methods. The EP(VLN) initiated electrode surface parades excellent sensitivity, steadiness, repeatability, and reproducibility for the redox action of RFN with enhanced peak currents as associated to BGPE. The oxidation peak currents of RFN are improved with increased concentrations of RFN in the range from 2.0 µM to 40.0 µM and the attained limit of detection (LOD) and limit of quantification (LOQ) are found to be about 28.69×10 -8 M and 95.66×10 -8 M, respectively. The prepared EP(VLN)MGPE was beneficial for the quantitative and qualitative investigation of RFN in medicinal samples.

Preparation of nanocrystalline Ni–Mo and Ni–Mo–ZrO2 coating and investigation of its corrosion resistance and wear behaviors

Nanocrystalline Ni–Mo and Ni–Mo–ZrO2 coatings were designed and successfully fabricated via electrodeposition process in direct current mode. Impacts of molybdate and ZrO2 nanoparticles, cathodic current density (ic) on surface, structure and performance of Ni–Mo alloy were analyzed. Electrochemical behaviors were evaluated by electrochemical impedance method in sodium chloride solution. A more compact and consistent surface morphology was prepared by introducing molybdate in nickel. Grain sizes of Ni–Mo alloy decreased as molybdate increased from 2 to 6 g L−1, and enlarged as ic increased. After incorporation of ZrO2, the grains initially decreased to 12 nm and later increased to 18 nm. The structure of the deposit is a face-centered cubic phase. With the increase of molybdate content, the preferential Ni (220) crystal plane was changed to oriented (111) plane. The Ni–Mo alloy comprises 91 wt% Ni and 5.4 wt% Mo. Ra of Ni–Mo–ZrO2 was 73 ± 4 nm. Ni–Mo alloys obtained at 20 mA cm−2 and 2 g L−1 molybdate possess the best corrosion-resistant behavior. Incorporation of ZrO2 can strengthen electrochemical stability and anti-wear behavior of Ni–Mo alloy. The inclusion of ZrO2 refined the grain size from 18 to 12 nm. The Ni–Mo/ZrO2 coatings electrodeposited under 2–4 g L−1 Na2MoO4·2H2O, 20–40 mA cm−2, 10–15 g L−1 ZrO2 have excellent wear and corrosion resistance.

Performance comparison of simultaneo us detection Heavy-Metal ions based on carbon materials electrochemical sensor

In this study, oak biomass carbon (BC) and BC-Au composite materials were synthesized by the pyrolysis method to construct BC-Au electrode and ionic liquid carbon paste electrode (CILE) composed of BC, graphite and 1-octyl-3-methylimidazolium hexafluorophosphate(IL) for simultaneous detection of Cd2+, Pb2+ and Hg2+. The obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectrum (Raman). The electrochemical performance of two sensors was studied using square wave voltammetry (SWV), cyclic voltammetry (CV), electrochemical impedance methods (EIS) and linear sweep voltammetry (LSV). The obtained results show that the detection performance of CILE was clearly better than BC-Au in terms of wide linear range(0.5 µM to 6.0 µM for Cd2+, Pb2+ and Hg2+) and high sensitivity(the detection limit toward Cd2+, Pb2+ and Hg2+ is 0.09 µM, 0.366 µM and 0.489 µM, respectively). In addition, a portable electrochemical sensing device matched with one-off CILE was constructed, which would enhance the ability for multiple electrochemical detection situations and show prospective applications for the detection of Cd2+, Pb2+ and Hg2+ in real lakes and cucumber samples.

Electrochemical Characteristics of Zn-Ion Hybrid Supercapacitors Based on Aqueous Solution of Different Electrolytes

Electrochemical behaviour of Zn cation based various aqueous electrolytes (ZnSO4, Zn(BF4)2, zinc di[bis(trifluoromethylsulfonyl)imide], Zn(TFSI)2, and zinc trifluoromethanesulfonate, Zn(OTf)2) has been studied in thin Zn foil∣ carbon cloth hybrid supercapacitor cell and compared with Zn(ClO4)2 aqueous electrolyte electrochemical characteristics using cyclic voltammetry, constant current charge/discharge and electrochemical impedance methods. The Ragone plots have been calculated from constant power measurements data. At moderate specific power values (10 kW kg−1) noticeable decrease of specific energies can be seen in the order of electrolytes: Zn(ClO4)2 ≥ Zn(BF4)2 > Zn(OTf)2 > Zn(TFSI)2 > ZnSO4. The stability of Zn-ion hybrid supercapacitor cells under study has been tested using the long lasting (up to 10000 cycles) constant current charge/discharge method and is very good for Zn(OTf)2, Zn(ClO4)2 and ZnSO4.

Synthesis, Characterization, Antimicrobial and Corrosion Inhibition Studies of Fused Oxadiazolo‐quinolines

AbstractA novel series of 2‐(4‐substituted phenyl)‐6/8‐substituted‐ [1,3,4] oxadiazolo[2′,3′:2,3][1,3]thiazino[6,5‐b]quinolin‐11(3aH)‐ones were synthesized. Their structures have been characterized using standard spectroscopic techniques such as Infrared, Nuclear Magnetic Resonance, and Mass Spectroscopy. All the newly synthesized compounds were screened for their antibacterial and antifungal activities by the cup plate diffusion method. Antimicrobial studies revealed that compounds showed good to significant activity against tested strains. One of the compounds was evaluated for corrosion inhibition studies by potentiodynamic polarization and electrochemical impedance method in 0.1 M hydrochloric acid solution for mild steel. The tested compound had exhibited a good inhibitory action against corrosion of mild steel in the medium investigated.

An experimental approach to find aniline-formaldehyde co-polymers as effective inhibitor on the interface of low carbon steel immersed in 0.5N HCl mixtures

The usefulness of aniline formaldehyde (AF), a modern water-soluble composite in 0.5 ​N hydrochloric acid as inhibitor of corrosion for mild steel, has been studied using weight reduction method, test of electrochemical impedance and potentiodynamic polarization methods. According to the findings by weight loss methods, 12ppm of AF co-polymer at room temperature i.e. about 35° ​± ​1°C for 3h duration shows best performance on metal surface and exhibit 93.44% Inhibitor efficiency. The above said results has also being reviled from other examination methods, which shows that the AF follows the Langmuir isotherm, as well as the adsorption properties of the sampling supports the results as maximum IE of 95.05%, using EIS. The tafel and linear polarization results of maximum IE was found to be 94.81% and 94.96% respectively which was well aligned with an atomic force microscope (AFM) for surface morphology and found AF to be best suited corrosion inhibitor showing mixed type of nature, at defined parameters.

A Ru/RuO2-Doped TiO2 Nanotubes as pH Sensors for Biomedical Applications: The Effect of the Amount and Oxidation of Deposited Ru on the Electrochemical Response.

In the field of orthopedic or dental implants, titanium and its alloys are most commonly used because of their excellent mechanical and corrosion properties and good biocompatibility. After implantation into the patient’s body, there is a high risk of developing bacterial inflammation, which negatively affects the surrounding tissues and the implant itself. Early detection of inflammation could be done with a pH sensor. In this work, pH-sensitive systems based on TiO2-Ru and TiO2-RuO2 combinations were fabricated and investigated. As a base material, Ti-6Al-4V alloy nanostructured by anodic oxidation was used. Ruthenium was successfully deposited on nanotubular TiO2 using cyclic polarization, galvanostatic and potentiostatic mode. Potentiostatic mode proved to be the most suitable. The selected samples were oxidized by cyclic polarization to form a TiO2-RuO2 system. The success of the oxidation was confirmed by XPS analysis. The electrochemical response of the systems to pH change was measured in saline solution using different techniques. The measurement of open circuit potential showed that unoxidized samples (TiO2-Ru) exhibited sub-Nernstian behavior (39.2 and 35.8 mV/pH). The oxidized sample (TiO2-RuO2) containing the highest amount of Ru exhibited super-Nernstian behavior (67.3 mV/pH). The Mott–Schottky analysis proved to be the best method. The use of the electrochemical impedance method can also be considered, provided that greater stability of the samples is achieved.