207 research outputs found
Characteristics of the citrate-based zinc-polyaniline secondary cell with supercapattery behavior
The electrochemical characteristics of zincāpolyaniline (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 60ā40 mW h g-1 and the specific power of 150ā350 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
Elektrohemijska sinteza elektroprovodnih polimera
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 odliÄnim izolatorima izmenjeno je sedamdesetih godina proÅ”log veka kada su nauÄnici uspeli da sintetizuju poiliacetilen Äija je provodljivost bila bliska metalnoj. Ova Äinjenica ukazala je na novo svojstvo polimernih materijala i lansirala potpuno novo multidisciplinarno nauÄno polje, popularno nazvano, sintetiÄki metali. Iako je danas pojmom elektroprovodnih polimera obuhvaÄena velika grupa jedinjenja koja su klasifikovana prema prirodi prenosioca naelektrisanja, naziv elektroprovodni polimeri se najÄeÅ”Äe koristi u literaturi upravo za polimerne materijala iz grupe sintetiÄkih metala koji poseduju elektronsku provodljivost kao posledicu specifiÄnosti 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 klasiÄnih neorganskih poluprovodnika, podrazumeva u mnogome drugaÄiji proces. Dopovanje elektroprovodnih polimera podrazumeva oksidaciju tokom koje se, u cilju održavanja elektroneutralnosti polimernog lanca, uvodi stehiometrijska koliÄina jona (anjona). Terminom dopovanje obuhvaÄena je i protonacija polimernog lanca kiselinom, u sluÄaju polianilina, a nedavno je potvrÄena i u sluÄaju polipirola. Kako je, na ovaj naÄin, uvedena velika koliÄina jona izmenjenja je polazna struktura elektroprovodnog polimera, tako da svojstva nastalog materijala zavise u velikoj meri od svojstava dopanta. Iako su na poÄetku 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, poÅ”to se polimer dobija oksidacijom na elektrodama (anodama), Äime je izbegnuta upotreba oksidacinog sredstva i omoguÄena veÄa ÄistoÄa proizvoda. Sa druge strane, elektroprovodni polimer je u veÄini sluÄajeva dobijen u obliku prevlake na elektrodi, pa je njegova dalja karakterizacija elektrohemijskim tenikama olakÅ”ana. Interesovanje za oblst sinteze elektroprovodnih polimera ne jenjava, pa je ovaj tekst posveÄen osnovnim principima elektrohemijskih postupaka sinteze sa posebnim osvrtom na najpopularnije elektroprovodne polimere, polianilin i polipirol
Electrochemical Water Treatment Devices
Paper published in 43rd International October Conference on Mining and Metallurgy - IOC 2011, October 12-15, 2011, Kladovo, Serbia: Proceedings, Bor : Technical Faculty, 2011
Electrochemical characterization of polyaniline electrode for use in electrochemical power sources
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
Characteristics of polyaniline lead - dioxide power sources
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
Electrochemical characterization of polyaniline electrode for use in electrochemical power sources
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
Sinteza i koroziono ponaÅ”anje polianilina na mekom Äeliku, bakru i aluminijumu iz benzoatnih rastvora
The electrochemical synthesis of polyaniline (PANI) on mild steel, aluminum and copper from the sodium benzoate solutions has been investigated. It has been shown that thin, highly adherent, polyaniline films on the investigated metals could be obtained by anodic oxidation with current densities in the range of 0.5 and 1.5 mA cm-2. The corrosion behavior of mild steel, aluminum and copper with polyaniline coating in 0.5 mol dm3 NaCl (pH 3) solutions, has been investigated by polarization technique. The corrosion current densities, porosity and protection efficiency was determined. It has been shown that polyaniline coating provided corrosion protection of all mentioned metals.U radu je ispitivana elektrohemijska sinteza polianilina (PANI) na mekom Äeliku, aluminijumu i bakru iz rastvora natrijum-benzoata i monomera anilina. Ustanovljeno je da se tanki, dobro adherentni, filmovi polianilina mogu formirati na svim ispitivanim metalima pri anodnim gustinama struja od 0,5-1,5 mA cm-2. Ispitivano je koroziono ponaÅ”anje metala sa prevlakom polianilina u rastvoru 0,5 mol dm-3 NaCl (3%). Ustanovljeno je da ove prevlake pružaju korozionu zaÅ”titu svim ispitivanim metalima u datoj korozionoj sredini
Characteristics of polyaniline lead - dioxide power sources
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
Electrochemically deposited nano fibrous polyanilne for amperometric determination of glucose
Electrochemical deposition of polyaniline (PANI) on graphite electrode was performed galvanostaticaly at constant current density in the range of 1.0 ā 5.0 mA cm-2 from aqueous acidic electrolyte containing aniline monomer. Based on ratio of doping/dedoping\ud
charge capacities, it was estimated that current density of 2.0 mA cm-2 was optimal. The structure of the electrochemically synthesized PANI was fibrous, uniform and three dimensional with highly developed surface. Immobilization of glucose oxidise (GOx) was achieved by cross linking via glutaraldehyde and the efficiency of the immobilization was determined spectrophotometrically. Chronoamperometric curves were recorded at different glucose concentrations and used to estimate the apparent Michaelis constant, which was shown to be 0.27 mM. The storage stability of the PANI enzyme electrode was also estimated
Electrochemical Polymerization of Aniline
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
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