324 research outputs found
Electrochemical energy sources based on a metal | electroconducting polymers system from water solutions
No full textU ovom radu su ispitane mogućnosti primene polimera polianilina (PANI) i polipirola (pPu) kao katodnih materijala u kombinaciji sa anodama od Zn, Mg i Al za potencijalnu primenu u elektrohemijskim izvorima struje (EIE). PANI i PPu su polimerizaovani elektrohemijskim postulkom u rastvoru odgovarajučćeg monomera i HC1 i okarakterisan tehnikom ciklične voltametrije. Pokazano je da elektroda na bazi pPu, i ako poseduje dobre elektrohemijske karakteristike, nije pogodna za upotrebu u EIE usled intenzivne degradacije polimera. Rezultati ipitivanja elektrode na bazi PANI ukazali su na postojanje dve forme PANI (emeraldin i perningranilin), kao i na degradaciju PANI. Ispitan je uticaja rN vrednosti i različitih anjona na degradaciju PANI sa ciljem izbora pogodnog elektrolita za EIE i njegove dalje optimizacije. Izabran je elektrolit hlorid/citrat pri rN - 5 jer je u ovom rastvoru utvrđena smanjena korozija ispitivanih metala. Daljim ispitivanjima, pokazano je da je jedino Zn moguće koristiti u EIE.
Ispitano je i optimizovano u realnim uslovima ponašanje elektroda od PANI i Zn u rastvoru hlorid/citrat. Utvrđeno je da je iskorišćenje struje no Zn oko 95% za struje veće od 5 mA cm-2, pa je u realnom sistemu, radna površina PANI elektrode bila pet puta veća. Dobijene su dobre naponske karakteristike tokom 20 ciklusa rada, a napon otvorenog kola je bio stabilin u toku deset dana i iznosio je oko 1.4 V. Utvrđeno je da je samopražnjenje ovog sisema oko 1.5 % dnevno, što je u skladu sa samopražnjenjem sistema sa polianilinskim elektrodama.The possible application of polyaniline (PANI) and polypyrrole (pPy) as cathodic materials combined to Zn, Mg and Al as anodic materials in electrochemical power sources were investigated. Electrochemical polymerization of PANI and pPy was performed from HC1 solution containing suitable monomer while cyclic voltammetry technique was used for characterization. It was shown that, apart from its good electrochemical characteristics, pPy electrode was not suitable for use in electrochemical power sources, due to intensive degradation. It was observed that PANI excised in two different forms emeraldine and perningraniline salt and that degradation of PANI occurred as well.
Influence of pH and various anions on degradation of PANI was investigated in order to choose electrolyte for electrochemical power sources and its optimization. It was shown that in chloride/citrate electrolyte at pH~5, because on this pH values is reduced corrosion of investigated metals. Further investigation was shown that only Zn can be used in electrochemical power sources.
Behavior of the real system PANI and Zn electrode was investigated and optimized in chloride/citrate electrolyte. It was observed that current efficiency for Zn was about 95% for current grater than 5 mA cm-2, and because of that, in the real system working area of the PANI electrode was five times greater than Zn electrode. For such system, good voltage characteristics during working 20 cycles were obtained. The open circuit voltage of 1.4 V was stable during 10 days. It was observed that the self discharge of the system was about 1.5% per day, which is in accordance to the self discharge of systems with PANI electrode
Electrochemical formation and behavior of silver and lead chlorides as potential cathodes for quasi-rechargeable magnesium seawater cell
No full textPrimary seawater magnesium-based cell with AgCl or PbCl2 cathodes is widely used as power sources. In this paper, we consider the cyclic galvanostatic formation of silver and lead chlorides and their electrochemical behavior for potential applications in the new concept of the seawater quasi-rechargeable magnesium cell. For potential cells, the voltage for Mg alloy AZ63 and AgCl is ~ 1.5 V, and for the PbCl2, ~ 1 V. High discharge specific capacity, energy, and power are obtained under the very high discharge rate. It is also presented that systems could be potentially used in emergency situations for a few days up to a few weeks as a power source in the life-saving boat for sporadic emitting GPS-SOS tacking signals and night signal lights.This is the peer reviewed version of the following article: Popović, A.S., Jugović, D. & Grgur, B.N. Electrochemical formation and behavior of
silver and lead chlorides as potential cathodes for quasi-rechargeable magnesium
seawater cell. J Mater Sci: Mater Electron 34, 1155 (2023). [https://doi.org/10.1007/s10854-023-10558-9
Grgur Garbin († 1621), captain of artillerymen, and his house in Zadar
No full textU radu se na temelju arhivskih i terenskih istraživanja donose nove spoznaje o luneti portala s nekadašnje kuće obitelji Garbin u Zadru, danas ugrađenoj u kuću u Ulici Mate Karamana. Preciznije se blazonira grb u luneti portala te ga se dovodi u vezu s kapetanom zadarskih topnika Grgurom Garbinom. Plemićka obitelj Garbin podrijetlom je iz Paga, a jedna grana prešla je početkom 17. stoljeća u Zadar. Zaključuje se da je luneta portala izrađena malo nakon 1609. godine kada prema arhivskim dokumentima Grgur Garbin kupuje kuću u blizini samostana sv. Dimitrija u Zadru. Utvrđuje se položaj kuće te se donose novi arhivski podatci iz života Grgura Garbina i njegovih potomaka. Saznaje se da je njegov sin Ivan Grgur (Zan Gregorio) zanimanjem bio zlatar.On the basis of the conducted archival and field research, the author presents new knowledge regarding the portal lunette earlier home of the Garbin family in Zadar, today built into the front facade of the house in Mate Karaman Street. The author describes the coat of arms in the portal lunette, and consequently – since it shows a cannon and a male head with the characteristic hat – brings it into connection with Grgur Garbin, captain of the Zadar artillerymen. In the 17th century, this type of hat – decorated with long feathers and identical to the one on Garbin’s grave – made an integral part of the uniform of Venetian commanders holding the rank of captain; this counts for artillery units, too. The noble Garbin family originates from the island of Pag, and one family branch moved to Zadar at the beginning of the 17th century. It is concluded that the portal lunette was built just after the year 1609, when – according to the archival documents – Grgur Garbin had bought a house near the monastery of St. Demetrius in Zadar. The author sets the accurate location of Garbin’s house and brings fresh archival data from the life of Grgur Garbin and his descendants. Record on the death of Grgur Garbin, captain of the Zadar artillerymen, was entered into registry books under the date 25 January 1621, and he was buried in the church of St. Demetrius near his family home. Grgur Garbin had two sons, both born in Zadar – Marco Antonio, baptised on 29 April 1609, and Ivan Grgur, baptised on 21st March 1611. Based on recent archival research, the author further learned that Garbin’s son Ivan Grgur, who died in Zadar in 1646, was professional goldsmith
The initial characteristics of the polypyrrole based aqueous rechargeable batteries with supercapattery characteristics: Dataset
No full textThe data files contain 11 diagrams created in Origin and the underlying measurement data.
Fig. 1. Cyclic voltammogram of the PPy electrode in 2 M NH4Cl and 1.1 M ZnCl2 a) Galvanostatic polymerization of pyrrole from 1 M HCl and 0.1 M pyrrole, b) Polarization curve (v = 1 mV s-1) of the zinc electrode in 2 M NH4Cl and 1.1 M ZnCl2.Fig. 2. a) The dependence of the PPy potentials over time on applied currents, b) The dependence of the voltage over time on applied currents of Zn|PPy cell.Fig. 3. The dependence of the charge-discharge capacity (left) and specific capacity (right) on applied current. Inset: Coulombic efficiency on applied current and specific current based on PPy mass.Fig. 4. Cyclization of the Zn|PPy cell. Inset: The dependence of the PPy specific charge-discharge capacity on cycle number.Fig. 5. Electrochemical formation of PPy, PbO2 and PbSO4Fig. 6. Cyclic voltammograms of the investigated materials in 1 M H2SO4 and 0.5 M (NH4)2SO4Fig. 7. Charge-discharge curves of the investigated materials for the different currents.Fig. 8. The dependence of charge-discharge capacity (left) and specific capacity based on PPy mass (right) on applied current. Inset: The dependence of the Coulombic efficiency (C.E.), for PPy end discharge potentials of –1 V (○) and –0.45 V (), on specific discharge current. Fig. 9. Cyclization of the PPy|PbO2 cell with an applied current of 6 mA. Inset: dependence of the charge-discharge voltage on specific capacity based on PPy.Fig. 10. Cyclization of the PbSO4|PPy cell with an applied current of 6 mA. Inset: dependence of the charge-discharge voltage on specific capacity based on PPy.Fig. 11. The dependence of the charge-discharge voltages on the specific capacities based on active masses at a current of 6 mA (1 mA cm-2), of the investigated cells.Supporting dataset for the article: Grgur, B.N., Janačković, M., Jugović, B.Z., Gvozdenović, M.M., 2019. The initial characteristics of the polypyrrole based aqueous rechargeable batteries with supercapattery characteristics. Materials Science and Engineering B: Solid-State Materials for Advanced Technology 243, 175–182. [https://doi.org/10.1016/j.mseb.2019.04.013]Related to: [https://hdl.handle.net/21.15107/rcub_dais_5762]Software requirements: Origin 8 and laterTo view the files use the free standalone application Origin Viewer: https://www.originlab.com/viewer
Electrochemical synthesis and characterization of poly(o-toluidine) as high energy storage material
No full textPoly(o-toluidine) (POT) is electrochemically synthesized on graphite electrode at
constant current density of 1.5 mA cm-2 from aqueous electrolyte of 1.0 mol dm-3 H2SO4 and
0.25 mol dm-3 o-toluidine. Electrochemical characterization of POT electrode is performed
using cyclic voltammetry, Mot Schottky analysis and galvanostatic measurements at different
currents. POT electrode exhibited high energy storage features, with specific energy up to
17.5 Wh kg-1 and specific power up to 3300 W kg-1. Cyclic stability exceeding 90% is
obtained over 2000 charge/discharge cycles at 13.1 A g-1 indicating the perspective
application of POT electrode as energy storage material.This is Accepted Manuscript of the following article: Milica M. Gvozdenović, Braninir Z. Jugović, Bojan M. Jokić, Enis S.Džunuzović, Braninimir N. Grgur, Electrochemical synthesis and characterization of poly(o-toluidine) as high energy storage material, Electrochimica Acta (2019), vol. 317. pp. 746-752, [http://dx.doi.org/10.1016/j.electacta.2019.06.046
Korozija čelika sa kompozitnim prevlakama na bazi polianilina
No full textThe chemically synthesized polyaniline in the powdered form by the procedure recommended by IUPAC is reprotonated using sulfamic, citric, succinic and acetic acid. Typical procedures for corrosion protection investigations based on UV-vis characterization, linear polarization measurements and optical microscopy investigations are developed with composite coatings based on well-characterized polyaniline doped with benzoate. The UV-vis spectroscopy is applied to estimate doping degree of the reprotonated samples. The estimated doping degrees are as follows: the polyaniline doped with sulfamic acid 0.28, with succinic acid 0.18, with citric acid 0.15 and with acetic acid 0.13. The composite coatings are prepared by mixing the alkyd based commercial paint with 5 wt.% of the reprotonated samples and painted on mild steel. Using linear polarization method, the polarization resistances of the composite and base coatings are determined in 3% NaCl over time. It is shown that initial oxidation state of the polyaniline, determined the values of polarization resistance which decrease in the following order: Rp(sulfamic) > Rp(succinic) > Rp(citric) > Rp(acetic) ~ Rp(base coating). For all composite coatings, increases in the corrosion potentials are observed during the time, while for the base coating decrease.
The higher area steel samples with base and composite coatings are also immersed in 3% NaCl. The corrosion current density is determined after 100 h in site using ASTM 1,10-phenanthroline method. The samples are also visually inspected, and by the optical microscope. It is shown that composite coatings reduce the possibility of blister formations and delamination. The corrosion current density and the appearance of the corrosion products closely follow the initial oxidation state of the polyaniline...Hemijski sintetisani polianilin u praškastoj formi postupkom preporučenim od strane IUPAC-a je reprotoniran pomoću sulfaminske, limunske, ćilibarne i sirćetne kiseline. Procedura za ispitivanje zaštite od korozije čelika zasnovana na UV-vis karakterizaciji, merenju linearne polarizacione otpornosti i ispitivanju optičkom mikroskopijom je razvijena na kompozitnom premazu zasnovanom na okarakterisanom polianilinu dopovanom benzoatom. UV-vis spektroskopija je primenjena za procenu stepena dopovanja reprotonovanih uzorka. Procenjeni stepeni dopovanja su bili sledeći: polianilin dopovan sa sulfaminskom kiselinom 0,28, sa ćilibarnom kiselinom 0,18, sa limunskom kiselinom 0,15 i sa sirćetnom kiselinom 0,13. Kompozitni premazi su pripremljeni mešanjem komercijalnog premaznog sredstva na bazi alkidne smole sa 5 mas.% reprotoniranih uzoraka polianilina i naneti na čelik. Koristeći metodu linearne polarizacije, određene su vrednosti polarizacione otpornosti kompozitnih i osnovnog premaza u 3% NaCl tokom vremena. Pokazano je da početno stanje oksidacije polianilina određuje vrednosti polarizacione otpornosti koja se smanjuje u sledećem redosledu: Rp (sulfaminska) > Rp (ćilibarna) > Rp (limunska) > Rp (sirćetna) ~ Rp (osnovni premaz). Kod svih kompozitnih premaza, tokom vremena je uočeno povećanje korozionog potencijala, dok je kod osnovnog premaza uočeno smanjuje.
Uzorci čelika veće površine sa osnovnim i kompozitnim premazima su takođe ispitani u 3% NaCl. Gustina struje korozije je određena nakon 100 h, određivanjem koncentracije jona gvožđa u rastvoru, koristeći ASTM 1,10-fenantrolin metod. Uzorci su takođe vizuelno pregledani i ispitani optičkim mikroskopom. Pokazano je da kompozitni premazi smanjuju mogućnost formiranja plikova i delaminacije. Gustina struje korozije i pojava korozionih produkata blisko prate početno oksidaciono stanje polianilina..
Osnovni principi i primena fotoelektrohemijskih reakcija
No full textThe paper discusses the basic principles of photoelectrochemistry and photo electrochemical reactions. Considered the application photoelectrochemicl cells in the conversion of the sun iradiation energy into electricity. In addition, the working principle of new types of fuel photoelectrochemical fuel cells that can simultaneously produce electricity and perform degradation of polluting organic substances is discussed.U radu su razmatrani osnovni principi fotoelektrohemije i fotoelektrohemijskih reakcija. Razmatrana je primena fotoelektrohemijskih ćelija u konverziji energije zračenja Sunca u električnu energiju. Takođe, razmatran je i princip rada novih tipova fotoelektrohemijskih gorivnih galvanskih ćelija koji simultano mogu proizvoditi električnu energiju i vršiti degradaciju zagađujućih organskih materija
Application of polypyrolle based electrode materials in conversion and accumulation of electrical energy
No full textProblematika ove doktorske disertacije izložena je u dve tematske celine. Prva je posvećena razmatranju elektrode na bazi elektrohemijski formiranog plipirola (PPY) kao elektrodnog materijala u konverziji energije, dok se druga celina odnosi na razmatranje elektrohemijski formirane elektrode na bazi PPY kao katodnog i anodnog materijala za primenu u akumulaciji električne energije na bazi vodenih rastvora elektrolita. Elektroda na bazi PPY formirana je anodnom oksidativnom polimerizacijom pirola na elektrodi od staklastog ugljenika u uslovima konstantne gustine struje (galvanostatski). Za potrebe razmatranja fotoelektrohemijskog ponašanja elektrode na bazi PPY, elektrohemijska sinteza je sprovedena u vodenom rastvoru elektrolita koji je sadržavao pored pirola natrijum-nitrat i azotnu kiselinu. Polimerizacija je ostvarena anodnom gustinom struje od j = 1,0 mA cm-2 u trajanju od 3 h.
Za razmatranje PPY kao elektrodnog materijala u akumulaciji električne energije, elektrode na bazi PPY dobijene su iz vodenog rastvora 1,0 mol dm-3 HCl hlorovodonične kisline kada su razmatrane kao katode u sistemu ZnPPY, dok je za razmatranje u sistemima PPYPbO2, odnosno PbSO4PPY korišćen vodeni elektrolit 1,0 mol dm-3 H2SO4. Elektrohemijsaka polimerizacija je ostvarena u galvnostatskim uslovima, gustinom struje od 2 mA cm–2 u trajanju od 1 h i 0,3 h za sisteme PPYPbO2 i PbSO4PPY respektivno.
Za potrebe fotoelektrohemijskih eksperimentata formirane su elektrode na bazi bakar-sulfida, i PPY modofikovane bakar-sulfidom, korišćenjem postupka naizmenične jonske adsorpcije i reakcije (SILAR). Kao rastvor katjonskog prekursora korišćen je vodeni rastvor 0,050 mol dm-3 bakar(II) - nitrata, dok je za formiranje sulfida korišćen rastvor 0,10 mol dm-3 natrijum - sulfida. Ispitana su fotoelektrohemijska svojstva elektrode od PPY, bakar-sulfida i PPY modifikovane bakar-sulfidom, u potenciostatskim uslovima u anodnoj i
katdnoj oblsti, u mraku i pri osvetljenju, u vodenom elektrolitu sastava 0,5 mol dm-3 NaNO3 i 0,2 mol dm-3 tiouree i 0,025 mol dm-3 Na2S.
Ispitivane su elektrohemijske i električne karakteristike sistema ZnPPY, PPYPbO2 i PbSO4PPY. Utvrđeno je da ZnPPY ćelija sa vodenim rastvorom elektrolita sastava 2,0 mol dm-3 NH4Cl i 1,1 mol dm-3 ZnCl2, ima prosečan napon pražnjenja od 0,85 V i specifični kapacitet pražnjenja od 52 mAh g-1. PPYPbO2 ćelija sa vodenim rastvorom elektrolita sastava 1,0 mol dm-3 H2SO4 i 0,5 mol dm-3 (NH4)2SO4 ima prosečni napon pražnjenja od 0,9 V i specifični kapacitet pražnjenja od 88 mAh g-1. Prosečan napon pražnjenja za PbSO4PPY ćeliju iznosio je 0,65 V, a specifični kapacitet pražnjenja 50 mAh g-1. Specifična energija pražnjenja do radnog potencijala od 0,5 V, efikasnost iskorišćenja energije i specifična snaga su pocenjenje na 45 mWh g-1 (56%), 326 mW g-1 za Zn|PPY ćeliju; 76 mWh g-1 (45%), 584 za PPY|PbO2 ćeliju 37 mWh g-1 (51%), 574 mWh g-1 za PbSO4|PPY ćeliju. Na osnovu ovih vrednosti pomenute ćelije su svrstane u tzv. superkapabaterije.The problematics of this dissertation is dedicated to application of electrochemically formed polypyrrole as electrode material in conversion of electrical energy and cathodic and anodic material in systems for accumulation of electrical energy with aqueous electrolytes. In both cases PPY electrode was form by electrochemical anodic polymerization of pyrrole monomer on glassy carbon electrode at constant current (galvanostatially). Depending on the further application, different composition of electrolytes was used, for PPY used in photoelectrochemical investigations, nitrate based electrolyte was used, while chloride based and sulfate based electrolytes were used for application of PPY as electrode material in electrochemical cells: ZnPPY and PPYPbO2, PbSO4PPY respectively.
Coper-sulfate electrode and coper-sulfate modified PPY electrode were formed by SILAR process on glassy carbon and PPY electrochemically formed on glassy carbon electrode. Cationic precursor solution was 0.050 mol dm-3 copper (II) – nitrate, and 0.10 mol dm-3 sodium sulfide as a solution of anionic precursor. Photo electrochemical behavior of these electrodes was investigated at constant anodic and cathodic potentials in dark and under illumination in water electrolyte consisted of 0.5 mol dm-3 NaNO3, 0.2 mol dm-3 tiourea and 0.025 mol dm-3 Na2S.
Electrochemical and electrical characteristics of the cells based on PPY based electrode comined zinc, lead oxide and lead sulfate electrodes in aqouous based electrolyte were determined. Zn|PPY cell in which PPY based electrode served as cathode and zinc electrode as anode with electrolyte composed of 2.0 mol dm-3 NH4Cl and 1.1 mol dm-3, exibited the open circuit voltage of 1.3 V, average discharge voltage of 0.85 V and specific discharge capacity of 52 mAh g-1. PPY|PbO2 cell in which PPY based electrode whas
anode and PbO2 as chatode with electrolyte composed of 1.0 mol dm-3 H2SO4 and 0.5 M (NH4)2SO4 had the open circuit voltage of 1.5 V, average discharge voltage of 0.9 V, and specific discharge capacity of 88 mAh g-1. PbSO4|PPY cell with PPY cathode and lead sulfate anode with the same sulfateelectrolyte had the open circuit voltage of 1.1 V, average discharge voltage of 0.65 V and specific discharge capacity of 50 mAh g-1. The specific discharge energy to the useful discharge potentials of ~ 0.5 V, charge-discharge energy efficiency, as well as specific power, were estimated to 45 mWh g-1 (56%), 326 mW g-1 for Zn|PPy cell; 76 mWh g-1 (45%), 584 for PPY|PbO2 cell, and 37 mWh g-1 (51%), 574 mWh g-1 for PbSO4|PPY cell. Based on estimated specific energy and power, the investigated cells were classified as “supercapattery” type of electrochemical power sources
Hibridni superkondenzatori akumulatorskog tipa na bazi provodnih polimera
No full textThe electrochemically synthesized polypyrrole and lead-lead sulfate are examined as a potential electrodes for battery-type hybrid supercapacitors in acidic solution. 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 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. It is estimated that cell will lose 20% of initial capacitance after ∼500-600 cycles.
The electrochemically synthesized polyaniline and lead sulfate are investigated as a possible active material of the aqueous based hybrid asymmetric supercapacitors. The electrochemical characteristics of polyaniline (doping-dedoping reactions), as well as electrical characteristics (specific capacitance, capacity, energy, and power) of the PbSO4|PANI cell, are determined. The cell capacitance, ranging from 216 F g−1 to 230 F g−1 is determined. In the specific current range of 0.3–1.5 A g−1 based on the active masses, the specific energy decrease from 30 to 20 Wh kg−1, while specific power increased from 200 to ∼800 W kg−1. The specific capacity of the cell, slightly decreased from 47 Ah g−1 to 40 Ah g−1 by increasing the specific current. It is estimated that cell will lose 20% of initial capacitance after ∼550 cycles.
Based on the estimated specific energy and power, it is suggested that investigated cells could be classified as hydride asymmetric battery type supercapacitors оr “supercapattery” type of electrochemical power sources.Elektrohemijski sintetizovani polipirol i olovo-olovo sulfat ispitani su kao potencijalne elektrode za hibridne superkondenzatore akumulatora tipa u kiselom rastvoru. Pražnjenjem u strujnom opsegu od ~0,6-2,27 A g-1 na bazi aktivnih masa, određene su vrednosti specifični kapaciteti od 90-72 Ah kg-1, energija od 58-40 Wh kg-1 i snaga od 40-1350 W kg-1, sa specifičnom kapacitivnošću ćelije u opsegu od 300-250 F g-1. Sistem pokazuje ponašanje tipa akumulatora pri malim strujama pražnjenja, npr. <0,5 A g-1 i superkondenzatorsko ponašanje pri većom strujama pražnjenja. Procenjeno je da će ćelija izgubiti 20% početnog kapaciteta posle ~ 500-600 ciklusa punjenja i pražnjenja.
Elektrohemijski sintetizovani polianilin i olovo sulfat ispitani su kao mogući aktivni materijal hibridnih asimetričnih superkondenzatora. Određene su elektrohemijske karakteristike polianilina (reakcije dopovanja i dedopovanja), kao i električne karakteristike (specifična kapacitivnost, kapacitet, energija i snaga) ćelije. Određuene su kapacitivnosti ćelije, u opsegu od 216 F g-1 do 230 F g-1. Pri strujama pražnjenja u opsegu od 0.3-1.5 A g-1 na osnovu aktivnih masa, specifična energija se smanjuje sa 30 na 20 Wh kg-1, dok se specifična snaga povećana sa 200 na ~ 800 W kg-1. Specifični kapacitet ćelije, malo je smanjen sa 47 Ah g-1 na 40 Ah g-1. Procenjeno je da će ćelija izgubiti 20% početne kapacitivnosti nakon ~550 ciklusa.
Na osnovu procenjenih vrednosti specifične energije i snage, predloženo je da ispitane ćelije mogu biti klasifikovane kao asimetrični hibridni superkondenzatori akumulatorskog tipa ili a "superkapabaterijska" vrsta elektrohemijskih izvora energije
Fotoelektrohemijska ćelija na bazi nanocevi titan-dioksida modifikovanih gvožđe oksidom.
No full textThe fast reaction of forced hydrolysis of iron(III) nitrate in hypochlorite solution at room temperature, leads to the formation of mainly hematite, α-Fe2O3. Successive ion adsorption and reaction (SILAR) is applied to decorate an electrochemically formed TiO2 nanotube electrode. The anodic photoelectrochemical behavior of pure TiO2-NT’s and modified electrodes are investigated in a sulfate containing solution at pH=9.2. It is shown that such a modification leads to an increase of anodic photoactivity, as well as that at the same current density, the photoelectrochemical cell with a modified electrode operates at a voltage lower by 0.7 V. The band gap and flat band potentials are estimated, and the structure of the band gap and possible charge transfer reactions and mechanism are discussed.
The electrochemical oxidation of the urea in near neutral pH is investigated on platinum electrode. It is shown that oxidation reaction is practically inhibited up to the potentials of ~0.9 V. The same reaction is investigated onto electrochemically obtained titanium dioxide nanotubes modified by hematite using SILAR method. It is shown that such system possesses electrocatalytic activity at very low potentials, and activity can be further improved by the illumination of the electrode in the photo-assisted reaction. The possible application of the photoactive anode is considered in the application of urea based water electrolysis and urea based fuel cell.Brza reakcija prisilne hidrolize gvožđa (III) nitrata u rastvor hipohlorita na sobnoj temperaturi, dovodi do stvaranja uglavnom hematita, α-Fe2O3. Sukcesivna jonska adsorpcija i reakcija (SILAR) primenjena je za modifikaciju elektrohemijski formirane elektrode od TiO2 u obliku nanocevi. Anodno fotoelektrohemijsko ponašanje čistih TiO2-NT i modifikovanih elektroda ispitano je u rastvoru sulfata pri pH = 9.2. Pokazano je da takva modifikacija dovodi do povećanja anodne fotoaktivnosti, kao i da kod iste gustine struje fotoelektrohemijska ćelija sa modifikovanom elektrodom radi na naponu manjem za 0,7 V. Procenjena je vrednost širine energetske barijere i potencijala izravnatih zona. Diskutovano je o strukturi energetske barijere ispitivanih materijala, mogućim reakcijama i mehanizmu prenosa naelektrisanja.
Elektrohemijska oksidacija uree u rastvoru pH=9,2 je ispitana na platinskoj elektrodi. Pokazano je da je reakcija oksidacije praktično inhibirana do vrednosti potencijala od ~ 0,9 V. Ista reakcija je ispitana na elektrohemijski dobijenim nanocevima titan-dioksida modifikovanim hematitom koristeći SILAR metodu. Pokazano je da takav sistem poseduje elektrokatalitičku aktivnost pri veoma niskim potencijalima, a aktivnost se može dodatno poboljšati osvetljavanjem elektrode. Moguća primena fotoaktivne anode je razmatrana za primenu u elektrolizi vode na bazi uree i gorivne ćelije na bazi uree
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