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Electrochemical Energy Storage (EES) technologies are playing a significant role in the aspirations to decrease the usage of fossil fuels and move toward an environmentally conscious society. Due to the importance of EES technologies, more researchers are looking for an efficient and effective electrode material, which is the most important part of the EES system that possibly could result in much-needed advancements in the field. However, incoming researchers have a diverse backgrounds and as newcomers to the electrochemical community, they sometimes lack familiarity with the core concepts, well-established procedures, and methodologies that define the standards of the discipline. This issue's importance has been acknowledged, and various publications have been written to guide researchers in doing accurate evaluations. However, to the best of our knowledge, even though these publications demonstrate the methodologies and procedures for approaching the existing challenges none of them address the offered topic with an actual example. To address this gap, we present a step-by-step procedure for the electrochemical analysis of polypyrrole, a widely utilized conducting polymer with significant potential as an electrode material for supercapacitors and batteries.

Electrochemical synthesis was used to polymerize aniline and copolymerize aniline and m-aminobenzoic from aqueous acidic electrolyte containing aniline and aniline with different amount of m-aminobenzoic acid. These materials were obtained galvanostatically at graphite electrode at current density of 1.0 mA cm-2 from aqueous electrolyte containing 1.0 mol dm-3 HCl and different amount of monomers. The effect of self-doping due to meta positioned carboxylic group was observed in both synthesis parameters, morphology, degree of oxidation and electrochemical behaviour. The presence of m-aminobenzoic acid led higher copolymerization increasing with the increase of amount of m-aminobenzoic acid if comparing to polymerization potential of aniline. Moreover, the copolymer with equal amount of aniline/m-aminobenzoic acid showed electrochemical activity in neutral electrolyte which might be due to possibility of proton exchange process which can be expelled from the copolymer during oxidation process together by insertion of anions, making this material promising for use in electrochemical biosensors., Elektrohemijski postupak korišćen je za polimerizaciju anilina i kopolimerizaciju anilina i m-aminobenzoeve kiseline iz kiselog vodenog rastvora elektrolita sa različitim molskim odnosima anilina i m-aminobezoeve kiseline. Ovi materijali dobijeni su uslovima konstantne gustine struje od 1,0 mA cm-2 iz kiselog vodenog elektrolita koji je sadržavao 1,0 mol dm-3 HCl, anilin i m-aminobenzoevu kiselinu. Uticaj samo-dopovanja koji je posledica prisustva karboskilne grupe u meta položaju ispoljavao se u različitim parametrima sinteze, morfologiji dobijenih materijala, stepenu oksidacije i elektrohemijskom ponašanju. Prisustvo m-aminobenzoeve kiseline uslovilo je veći potencijal sinteze kopolimera u odnosu na polianilin koji je rastao sa porastom udela m-aminobezoeve kiseline. Kopolimer koji je dobijen iz elektrolita sa jednakim molskim odnosom anilina i m-aminobenzoeve kiseline pokazao je elektrohemijsku aktivnost u neutralnom elektrolitu koja može biti posledica razmene protona što ovaj materijal čini perspektivnim za praktičnu primenu u elektrohemijskim biosenzorima.

The initial corrosion behavior of AZ63 magnesium alloy was investigated in 1, 3, 5 and 7 wt.% NaCl solutions by means of corrosion potential, linear polarization, electrochemical impedance spectroscopy, and polarization measurements, during exposure in the corrosion media. Results show that the increase in chloride concentration provokes an increase in the corrosion rate. Based on the obtained kinetics parameters the mechanisms of anodic dissolution and hydrogen evolution reactions were discussed, and kinetic models were proposed. It is concluded that anodic dissolution proceeds under Temkin conditions and hydrogen evolution reaction depends on the surface coverage of Mg(OH)2 species.

Electrochemical oxidative polymerization at constant current density was used to produce polypyrrole (PPY) at graphite electrode from aqueous acidic electrolyte containing 0,1 mol dm-3 pyrrole and 1,0 mol dm-3 HCl. PPY electrode was than used as cathode while zinc electrode served as anode in electrochemical cell with an aqueous electrolyte containing 2,0 mol dm-3 NH4Cl and 1,1 mol dm-3 ZnCl2. The relevant electrochemical parameters of this cell were evaluated from electrochemical experiments. It was observed that charge of Zn|PPY cell started at voltage between 0,5 and 0,7 V and proceeded up to 1,5 V. Charge/discharge of the cell was dependent on charge/discharge current density with open circuit voltage of the fully discharged cell around 1,3 V. The estimated values of specific energy were between 46 and 68 W h kg-1 while specific power values were between 125 and 380 W kg-1, which suggested that Zn|PPY cell had “supercapaterry” behavior., Elektroda na bazi polipirola (PPY) dobijena je elektrohemijskom oksidativnom polimerizacijom na grafitnoj elektrodi u uslovima konstantne gustine struje. Kao elektrolit za sintezu, korišćen je vodeni rastvor 0,1 mol dm-3 pirola i 1,0 mol dm-3 HCl. Formirana je elektrohemijska ćelija u kojoj je elektroda na bazi PPY korišćena kao katoda dok je anoda bila elektroda od cinka, a elektrolit se sastojao od vodenog rastvora 2,0 mol dm-3 NH4Cl i 1,1 mol dm-3 ZnCl2. Procena relevantnih elektrohemijskih i električnih parametara ove ćelije bazirana je na elektrohemijskim eksperimentima. Utvrđeno je da je proces punjenja/pražnjenja zavisio od struje punjenja/pražnjenja, punejnje ćelije započinje na naponu između 0,5 i 0,7 V, a završava se na naponu od oko 1,3 V. Procenjene vrednosti energije bile su između 46 i 68 W h kg-1, dok se za specifičnu snagu dobijaju vrednosti između 125 i 380 W kg-1, što ukazuje na superkapabaterijska svojstva Zn|PPY ćelije.

The electrochemical characteristics of zinc–polyaniline (PANI) secondary cell in the electrolyte containing 0.8 M Na citrate, 0.3 M NH4Cl and 0.3 M ZnCl2 is investigated. Based on the measurements of potentials and voltage of the cell during charge/discharge for the currents in the range of 18 to 45 mA, the specific electrode capacity of 85 to 55 mA h g-1, the specific energy of 60–40 mW h g-1 and the specific power of 150–350 mW g-1, is determined. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON172046: Electrochemical synthesis and characterization of nanostructured functional materials for applications in new technologies]

The electrochemically synthesized polypyrrole (PPy) is investigated as a possible active material of the low-cost aqueous based secondary power sources in combination with zinc, lead oxide, and lead sulfate. The discharge capacity of the polypyrrole in the chloride-based electrolyte (for the Zn|PPy cell) is in the range 110 mAh g −1 of PPy, while in the sulfate-based electrolyte ∼150 mAh g −1 of PPy (for the PbSO 4 |PPy and PPy|PbO 2 cells), which is close to the theoretically calculated values. Electrochemical and electrical parameters, reactions in the cells, specific capacity, specific capacitance, energy, and power, for the Zn|PPy, PPy|PbO 2 and PbSO 4 |PPy cells are determined. In addition, the energy efficiency, for the considered systems is estimated. Obtained values of the specific power and energy, could classified investigated systems as a battery type hybrid superacapacitors or “supercapattery”. © 2019 Elsevier B.V.

Due to unique properties of intrinsically conducting polymers (ICP) such as: electrical conductivity, reversible electrochemistry, optical activity, biocompatibility, environmental and corrosion stability, they still represent a base for both theoretical and practical studies. The mentioned properties open up possibilities for practical application in the field of electrochemical systems for energy storage and conversion, sensors, biosensors, antistatic coatings, magnetic shielding, active corrosion protection etc. Bearing in mind that nanostructurization of materials lead to improvement of physical and chemical properties, there is a growing interest in the development of nanosized ICP. Nanosized ICP can be prepared by both chemical and electrochemical procedures. Although chemical synthesis is a common approach, there are also not a few studies of electrochemical synthesis of ICP. The aim of this paper is to review literature dedicated to electrochemical formation of nanostructured ICP with special attention dedicated to polyaniline and polypyrrole as the most popular ICPs., Interesovanje za elektroprovodne polimere kako u teorijskom tako i praktičnom smislu utemeljeno je u jedinstvenim svojstvima ovih materijala, kao što su: kontrolisana električna provodljivost, reverzibilna oksidacija redukcija (dopovanje/dedopovanje), optička aktivnost, bio-kompatibilnost, korziona postojanost itd. Ova svojstva otvaraju mogućnosti praktične primene u oblasti elektrohemisjkih primarnih i sekundarnih izvora električne energije, elektrohemijskih kondenzatora, senzorima, biosenzorima, aktivnoj zaštiti od korozije. Imajući u vidu da nanostrukturizacija materijala dovodi do značajnog poboljšanja fizičkih i hemijskih svojstava materijala postoji veliko interesovanje za proučavanje nanostruktuirasnih elektroporvodnih polimera. Nanostruktuirani elektroprovodni polimeri mogu se dobiti hemijskim i elektrohemijskim postupcima sinteze. Iako je hemijska sinteza zastupljenija, u literaturi može se naći značajan broj radova posvećen elektrohemisjkom formiranju nanostruktuiranih elektroprovodnih polimera, pa je upravo i ovaj tekst posvećen toj probelmatici, u prvom redu elektrohemisjkom formiranju nanostruktura polianilina i polipirola kao najznačajnijih predstavnika elektroprovodnih polimera.

Magnetic particles (MAG), obtained by standard procedure of coprecipitation of Fe2+ and Fe3+ in an excess of ammonia, and polyaniline modified magnetic particles MAG-PANI were used as carriers for immobilization of α-amylase from Bacillus licheniformis. The formation of a polyaniline layer (PANI) on MAG particles was achieved by chemical polymerization of aniline. Immobilization was carried out by adsorption, as a simple, inexpensive and fast method that allows retention of a large portion of the initial activity of the immobilized enzyme. FTIR spectroscopy was used to characterize the obtained particles and to confirm changes dueto formation of a PANI layer and conjugation of α-amylase on the particle surfaces. Particle size distribution was bimodal and three-modal for MAG and MAG-PANI, respectively. Appearance of a fraction of smaller MAG-PANI particles than MAG particles could be attributed to the formation of PANI particles without the MAG core. Measured values of Zeta potential for MAG-PANI were higher as compared to MAG indicating stabilization of particles in the presence of PANI. Relevant kinetic parameters for immobilized enzyme were determined from the Hanes plot. The apparent Km constant was 1.91 and 1.48 g L–1 for MAG-A and MAG-PANI-A, respectively, while Vm was 0.19 g L–1 min–1 for MAG and 0.32 g L–1 min–1 for MAG-PANI. The obtained values of Km indicated that modification of MAG by PANI enhanced kinetic properties of the immobilized enzyme. Moreover, the modification of MAG by PANI showed the increase in both pH and thermal stabilities of the immobilized enzyme. Studies of the operational activity of the immobilized enzyme on MAG-PANI have shown that 98.8% of starch was hydro-lyzed over 20.0 min. In the first cycle in the packed bed reactor operated in a recycling mode, but approximately five times longer period was required to hyd-rolyze 93.5 of starch in the fifth cycle. In the continuous packed bed reactor without recycling, the degree of starch hyd

Electroconducting polymers from the group of synthetic metals are extensively investigated due to numerous properties perspective in practical application. These materials may be synthesized by both chemical and electrochemical procedures. Chemical synthesis is suitable when bulk quantities of the polymer are necessary and up to date it presents dominant commercial method of producing electroconducting polymers. Nevertheless, the electrochemical synthesis has its advantages; it avoids usage of oxidants since conducting polymeric material is obtained at anode upon application of positive potential, leading to increased purity. On the other hand, since the polymer is deposited onto electrode, further electrochemical characterization is facilitated. Owing to actuality of the research in the field, this text aims to describe important aspects of electrochemical synthesis of electroconducting polymers, with special emphasis to polyaniline and polypyrrole., Tradicionalno shvatanje o polimerima kao odličnim izolatorima izmenjeno je sedamdesetih godina prošlog veka kada su naučnici uspeli da sintetizuju poiliacetilen čija je provodljivost bila bliska metalnoj. Ova činjenica ukazala je na novo svojstvo polimernih materijala i lansirala potpuno novo multidisciplinarno naučno polje, popularno nazvano, sintetički metali. Iako je danas pojmom elektroprovodnih polimera obuhvaćena velika grupa jedinjenja koja su klasifikovana prema prirodi prenosioca naelektrisanja, naziv elektroprovodni polimeri se najčešće koristi u literaturi upravo za polimerne materijala iz grupe sintetičkih metala koji poseduju elektronsku provodljivost kao posledicu specifičnosti molekulske strukture. Pored zahteva molekulske structure, koja podrazumeva konjugovani sistem dvostrukih veza, za provodljivost elektroprovodnih polimera neophodno je dopovanje. Termin dopovanje, iako preuzet iz terminologije klasičnih neorganskih poluprovodnika, podrazumeva u mnogome drugačiji proces. Dopovanje elektroprovodnih polimera podrazumeva oksidaciju tokom koje se, u cilju održavanja elektroneutralnosti polimernog lanca, uvodi stehiometrijska količina jona (anjona). Terminom dopovanje obuhvaćena je i protonacija polimernog lanca kiselinom, u slučaju polianilina, a nedavno je potvrđena i u slučaju polipirola. Kako je, na ovaj način, uvedena velika količina jona izmenjenja je polazna struktura elektroprovodnog polimera, tako da svojstva nastalog materijala zavise u velikoj meri od svojstava dopanta. Iako su na početku razvoja ove oblasti, elektroprovodni polimeri bili sintetizovani hemijskim postupcima, sticanjem uvida u mehanizam hemijske sinteze koja podrazumeva oksidativnu radikalnu polimerizaciju, postalo je jasno da se ovi materijali mogu dobiti i elektrohemijskim postupcima. Elektrohemijska sinteza ima prednosti, pošto se polimer dobija oksidacijom na elektrodama (anodama), čime je izbegnuta upotreba oksidacinog sredstva i omogućena veća čistoća proizvoda. Sa druge

Electroconducting polymers are promising materials to be used in various fields including: batteries, capacitors, electronic devices, corrosion, biosensors and sensors[1,6]. Polyaniline is probably the most investigated electroconducting polymer, due to low cost monomer, conductivity, environmental stability. Polyaniline can be obtained by chemical or electrochemical oxidative polymerization of aniline. Electrochemical synthesis is performed in anodic process directly from acidic aqueous electrolyte containing aniline. Polyaniline can be used as electrode material for electrochemical determination of ascorbic acid based on electrocatalytic oxidation of ascorbic acid.

Poly(aniline-co-(m-aminobenzoic acid)) was synthesized electrochemically at graphite electrode under galvanostatic conditions. Aqueous electrolyte for synthesis was consisted of HCl and different amount of aniline and m-aminobenzoic acid. The presence of the meta positioned carboxylic group in m-aminobenzoic acid influenced higher co-polymerization potential, different morphology and electrochemical behavior of copolymers compared to polyaniline. Electrochemical activity is achieved by proton exchange in neutral environment that can result in a faster charge/discharge process, which is in the case of PANI limited by slow anion exchange, making this material promising for consideration in super-capacitors and in biological system.

Polyaniline (PANI) was electrochemically synthesized on graphite electrode galvanostaticaly from aqueous solution of 0.25 mol dm-3 aniline and 0.5 mol dm-3 p-toluenesulfonic acid. Charge capacity available for the exchange and the total theoretical weight of polyaniline polymerized on graphite electrode was determined. Characterization polianiline electrode was performed by cyclic voltametry in 0.5 mol dm-3 HCl. Based on the PANI electrodes behavior during the cyclization, was tested the possibility of practical application of polyaniline doped p-toluenesulfonic acid as the anode material of secondary electrochemical power sources.

Polianilin je najproučavaniji elektroprovodni polimer. Ova popularnost polianilina je posledica jedinstvenih svojstava, delom nasleđenih od polimerne prirode, a delom ostvarenih provodljivošću. Najvažnija svojstva polianilina: postojanje više oksidacionih stanja, elektronska provodljivost, optička aktivnost, postojanost u spoljašnjoj sredini, mogućnost hemijske i elektrohemisjke sinteze i niska cena monomera nalaze primenu u mnogim oblstima: elektrohemisjkim sistemima za skladištenje i proizvodnju električne energije, elektronici, za izradu sensorskhih i biosenzorskih elektroda, za izradu antistatičkih i materijala mikrotalasnih i magnetnih štitova i u zaštiti metala i legura od korozije. Primena polianilina u zaštiti od korozije je prvenstveno motivisana potrebom zamene toksičnih materijala iz sistema prevlaka. Postoji dosta literaturnih podataka iz ove oblasti. Ipak, imajući u vidu raznovrsnost metala i legura, korozionih sredina, postupaka pripreme materijala, nanošenja prevlaka i vrsta prevlaka, kao i eksperimentalnih procedura i observacija, praktično je nemoguće uspostaviti jedinstven mehanizam antikorozione zaštite metala u prisustvu polianilina. Najcitiraniji i najpopularniji mehanizmi koji se mogu naći u literaturi obuhvataju barijerni mehanizam i mehanizam anodne zaštite., Polyaniline is probably the most investigated electroconducting polymer. This popularity is a result of its important features: existence of various oxidation states, electrical and optical activity, low cost monomer, red/ox reversibility, environmental stability, ease of both chemical and electrochemical synthesis etc. These unique features are partly inherited from its polymeric origin and partly aroused from its conductivity and could be considered for practical application in: electrochemical systems for energy storage and conversion, electronic devices, electromagnetic and microwave shielding materials, sensors, biosensors and corrosion protection as well. The motivation of application of polyaniline in corrosion protection of metals and alloys is replacement of environmentally hazardous materials, e.g. chromates in coating systems. Up to day, lot of studies on various metals both on iron, steels and non-ferrous metals and alloys were performed. The studies involve investigation on individual polyaniline coatings and polyaniline in coating systems. Owing to variation in experimental procedure (substrate, substrate preparation, coating type, corrosion environment, test method etc..) it is unlikely to propose unique mechanism for corrosion protection of metals in the presence of polyaniline. However, most of the literature is interpreted in terms of general mechanisms of corrosion protection, barrier and anodic protection.

Electrochemical polymerization of polyaniline (PANI) coating on copper electrode was performed galvanostatically in the current density range between 0.50 and 1.25 mA cm−2, from aqueous solution of 0.3 mol dm−3 sodium benzoate and 0.2 mol dm−3 aniline. The corrosion behavior of PANI coated copper and copper electrode exposed to 0.5 mol dm−3 sodium chloride solution was investigated by potentiodynamic and electrochemical impedance spectroscopy techniques. It was observed that thin PANI (5 μm) coating had provided efficient protection (∼96%) to copper in 0.5 mol dm−3 sodium chloride solution. Unusual initial impedance behavior to that normally observed with conventional organic coatings was attributed to dedoping of benzoate anions from the polymer coating.

Polyaniline (PANI) enzyme electrode was formed by immobilisation of Glucose oxidase (GOx) via glutaraldehyde into electrochemically polymerised PANI on graphite electrode. Electrochemical polymerisation of PANI on graphite was performed from aqueous solution of 1.0 mol dm−3 HCl and 0.25 mol dm−3 aniline at constant current density of 2.0 mA cm−2. Hronopotentiometric curves of the PANI enzyme electrode obtained at current density of 10 μA cm−2 were recorded in different glucose concentrations. The linearity response range was between 1.0 and 5.0 mmol dm−3 of glucose concentration. The estimated apparent Michaelis–Menten constant, was Km′ = 0.30 mmol dm−3, which is significantly lower than that of free enzyme.

Paper published in 43rd International October Conference on Mining and Metallurgy - IOC 2011, October 12-15, 2011, Kladovo, Serbia: Proceedings, Bor : Technical Faculty, 2011.

Polyaniline electrode (PANI) was formed electrochemically at graphite electrode. Electrochemical polymerization was performed at constant current density of 2.0 mA cm−2 from aqueous solution of 1.0 mol dm−3 HCl with addition of 0.25 mol dm−3 aniline monomer. Electrochemical characterization of the PANI electrode in chloride and chloride/citrate electrolyte was performed using cyclic voltammetry and galvanostatic measurement in order to study the influence of citrate ions on charge/discharge capability and cycling efficiency. It was observed that, for anodic potential 0.32 V, higher electrode capacity of PANI electrode in chloride/citrate electrolyte was obtained, comparing to chloride electrolyte, indicating positive effect of citrate ions on cycling characteristics. On the other hand, for higher anodic potential limit of 0.50 V, faster decrease of the electrode capacity in chloride/citrate electrolyte was observed. It was suggested that influence of both chloride and citrate anions had exhibited influence on electrochemical behavior of PANI electrode in citrate containing electrolyte.

In recent years, great focus has been placed upon polymer thin films. These polymer thin films are important in many technological applications, ranging from coatings and adhesives to organic electronic devices, including sensors and detectors. Electrochemical polymerization is preferable, especially if the polymeric product is intended for use as polymer thin films, because electrogeneration allows fine control over the film thickness, an important parameter for fabrication of devices. Moreover, it was demonstrated that it is possible to modify the material properties by parameter control of the electrodeposition process. Electrochemistry is an excellent tool, not only for synthesis, but also for characterization and application of various types of materials. This book provides a timely overview of a current state of knowledge regarding the use of electropolymerization for new materials preparation, including conducting polymers and various possibilities of applications.

Polyaniline (PANI) enzyme electrode was formed by immobilization of Glucose oxidase (GOx) via glutaraldehyde into electrochemicaly polymerized PANI on graphite electrode. Electrochemical polymerization of PANI on graphite was performed from aqueous solution of 1.0 mol dm-3 HCl and 0.25 mol dm-3 aniline at constant current density of 2.0 mA cm-2. Hronopotentiometric curves of the PANI enzyme electrode obtained at current density of 10 μA cm-2 were recorded in different glucose concentrations. The linearity response range was between 1.0-5.0 mmol dm-3 of glucose concentration. The estimated apparent Michaelis-Menten constant, was Km ′ = 0.30 mmol dm-3, which is scientifically lower than that of free enzyme.

Electrochemical polymerization of Polyaniline (PANI) film on aluminum electrode from aqueous solution of 0.20 mol dm-3 sodium benzoate containing 0.25 mol dm-3 aniline have been investigated using potentiodinamic and galvanostatic techniques. Corrosion behavior of aluminum and PANI coated aluminum electrode during initial exposure to 3% NaCl have been investigated using electrochemical potentiodimanic and impedance spectroscopy technique (EIS). It was observed that thin PANI coating of estimated thickness of 10μm had provided good initial corrosion protection of aluminum in3% NaCl, decreasing the corrosion current density at least 15 times.

Polyaniline (PANI) electrode was formed by electrochemical synthesis on graphite under galvanostatic condition at current density of 2.0 mA cm-2 from aqueous solution of 1.0 mol dm-3 HCl and 0.25 mol dm-3 aniline. Electrochemical characterization of the PANI electrode was performed in 0.5 mol dm-3 HCl using cyclic voltammetry and galvanostatic measurements. The overall charge capacity of the PANI electrode was estimated to be 0.154 mA h cm-2, corresponding to 25 % of the theoretical mass of PANI available for the dopant exchange. It was observed that during initial cyclization at low pH, the extent of PANI degradation products was insignificant and practically had no influence on the charge/discharge characteristics of the PANI electrode.

Polyaniline (PANI) anode, electrochemically synthesized on graphite electrode from sulfuric acid solution, and electrochemically formed thin film lead dioxide cathode, were investigated for possible applications as electrode materials in PANI | H2SO4 | PbO2 aqueous based rechargeable power sources. The stimulation of charge/discharge characteristics of the cell, based on half cell reactions investigations, was evaluated. Charging of the cell would occur in the voltage range of 1.2 and 1.7 V, while discharge would occur in the range of 1.3 and 1 V.

The immobilization of α-amylase via adsorption on magnetic particles coated with polyaniline was studied. The support was characterized by field emission scanning electron microscopy (FESEM). The obtained magnetic particles were agglomerates of nanoparticles with sizes below 100 nm. The effects of various factors on immobilization, including time, the initial enzyme concentration, pH, and temperature, were examined. The optimum pH, temperature, and time for immobilization were established to be 7, 45°C and 75 min, respectively. The maximum amount of adsorbed α-amylase of 10/100 mg support was determined at the 5 mg/mL enzyme concentration. It appeared that α-amylase was stabilized in terms of pH and temperature by adsorption on magnetic particles coated with polyaniline. The good agreement of the equilibrium data with the Langmuir isotherm model confirmed the monolayer coverage of enzyme molecules on the surface of magnetic particles, and the maximum adsorption capacity was found to be 55.6/100 mg support at 25°C. The biocatalyst retained 55.5 ± 1.63% of its initial activity after nine cycles of reuse in starch hydrolysis at 60°C in a batch reactor. The immobilized enzyme also showed very good storage stability.

Novel TiO2-PANI core-shell nanocomposite, prepared by in situ oxidative polymerization of aniline in the presence of TiO2 nanoparticles surface modified with vitamin B6, was used to reinforce epoxy resin. The size of prepared TiO2 nanoparticles and TiO2-PANI nanocomposite were determined by a transmission electron microscopy (TEM). The surface modification of TiO2 nanoparticles was confirmed by FTIR and UV-vis spectroscopy, while the morphology of PANI and TiO2-PANI nanocomposite was investigated by scanning electron microscopy (SEM). The influence of TiO2-PANI nanocomposite on glass transition temperature, dielectric and dynamic mechanical properties, thermooxidative stability, mechanical and anticorrosion properties of epoxy based nanocomposites was investigated and compared to the properties of epoxy/PANI nanocomposites. It has been observed that the glass transition temperature of epoxy resin increases after introduction of PANI and TiO2-PANI nanocomposite, as well as with increasing their content. Prepared nanocomposites exhibited higher value of dielectric constant than pure epoxy resin. Epoxy based coating containing TiO2-PANI nanocomposite showed lower dielectric loss, higher hardness and better anticorrosion properties than pure epoxy resin and epoxy/PANI nanocomposite.

The potential characteristics of graphite felt electrodes, modified by iron oxide, for oxygen reduction are evaluated. Modification is carried out by Successive Ion Layer Adsorption and Reaction (SILAR) method, using a solution of ferric nitrate in methanol for the adsorption of ions, and a solution of sodium hypochlorite for reaction. The reaction activity of the oxygen reduction from the air, in sodium sulfate based solution varying the number of SILAR cycles, as well as the influence of pH is investigated. By comparing the activity with pure platinum, similar activity is obtained at pH = 9.2, as well as good electrode stability. Possible mechanism of the oxygen reduction on the graphite felt modified by iron oxide is discussed.

The electrochemically synthesized polypyrrole and lead-lead sulfate is examined as a potential electrodes for battery-type hybrid supercapacitors in acidic solution. The device exhibits battery-type behavior at low discharge rate, e.g. <0.5 A g−1, and supercapacitors-type behavior at a higher discharge rate. Discharge in the specific current range of ∼0.6–2.27 A g−1 based on the active masses, can deliver capacity of 90–72 Ah kg−1, energy of 58–40 Wh kg−1 and power of 40–1350 W kg−1, with the specific capacitance of the cell in the range of 300–250 F g−1. The experimentally obtained values are compared with theoretical.