untitled ISSN 215 Corrosio Nady Hash 1 Chemistry Dep 2 Chemistry Dep * Corresponding Tel.: +966.53.55 ARTICLE IN DOI: 10.5155/e Received: 10 Oc Received in rev Accepted: 14 No Published onlin Printed: 31 Mar KEYWORDS Impedance Amino acids Polarization Carbon steel Corrosion inhib Potentiodynam 1. Introduct Carbon s industries b fabrication o tanks and p main cause localized nat hostility of c strong acidic made on th chloride bri generally red the metal [4 assessed as sulfate soluti The mo compounds π electrons The initial m the adsorpti The adsorpt facilitated by S) as well as metals can formation of 53‐2249 (Print) on inhibit hem El‐Saye partment, Faculty of partment, Faculty of g author at: Chemis 589807. Fax: +2.084 FORMATION eurjchem.7.1.14‐18 ctober 2015 vised form: 11 Nov ovember 2015 ne: 31 March 2016 rch 2016 S bition mic polarization tion steel, an alloy o because of its l of reaction vess ipes. Chloride of pitting corr ture, leading to chloride ion is a c anionic natu he corrosion b ine [1]. Corro duced by using 4‐13]. Various good corrosion ions [14‐20]. ost efficient c containing elec in their triple mechanism in a ion of the inhib tion of the inhi y the presence o s aromatic ring also be viewe f chelate on the / ISSN 2153‐225 ht Europ tion of car ed 1,2,* f Science, Fayoum f Science and Arts, stry Department, Fa 4.6370025. E‐mail a 8.1331 ember 2015 f iron and carb low cost and sels, girders, m ions are usuall rosion in carbo passive layer b as a result of its re [3]. A lot o behavior of st osion caused b inhibitors to m thiadiazole com n inhibitors for corrosion inhi ctronegative fu or conjugated any corrosion i bitor on the m ibitor on the m of hetero atoms g. The inhibition ed as a proces e metal surface European Journ Europ 57 (Online)  20 ttp://dx.doi.org pean Jo Journal web rbon stee University, Fayoum Aljouf University, Q Faculty of Science, F address: nhmahmo ABSTRACT The corrosio chloride solu corrosion rate polarization impedance da model to exp The corrosion molecules on remarkably h to depend on process is bas surface. Resul mixed‐type in Cite this: Eur. on is used in va easy availabilit machine parts, r ly recognized a on steel due to breakdown [1,2 s size, diffusivit f research has teel in carbon by chloride ca minimize the att mpounds have r steel in acidi ibitors are or unctional group d double bonds inhibition proc metal surface [2 metal surface c s (such as N, O, n of the corros ss that involve e, which involve al of Chemistry 7 pean Journal of C 016 Atlanta Pub /10.5155/eurjch ournal bpage: www. el in chlor m City, 63514, Egyp Qurayate City, 2014 Fayoum University, od@ju.edu.sa (N.H. n inhibition of utions using am e was calculated technique and ata were fitted plain the behavi n inhibition pro the metal surfa igh corrosion in n the structure o sed on the adsor lts obtained from nhibitor. . J. Chem. 2016, arious ty for rivets, as the o their 2]. The ty and been nated‐ an be tack of e been ic and rganic ps and s [21]. cess is 22,23]. can be P and ion of es the es the tran sur bon nuc wid as How that are con plan pro com form inh obt of a glut thre mol carb rate resp pot imp 7 (1) (2016) 14‐ Chemistry lishing House LL hem.7.1.14‐18.1 of Che .eurjchem.co ride soluti t 4, Kingdom of Saud Fayoum City, 6351 El‐Sayed). carbon steel w mino acids as e d in the absence electrochemica to theoretical d or of the alloy/ cess was found ace. Cysteine, hi nhibition efficien of the amino ac rption of the ami m potentiodynam 7(1), 14‐18 nsfer of electr face of the meta nd. In this case, cleophilic cente de range of com potential inhib wever, a close t some of them expensive. The ntinuing search nt extracts, s oducts [26‐28]. mponents of livi mation. Sever ibitory potenti ained from suc amino acids as g In this work so tamic acid, p eonine, cystein lecules were us bon steel electr e and corrosion pect, conventi tentiodynamic p pedance spectr ‐18 LC ‐ All rights re 1331 emistry m ions by so di Arabia 14, Egypt. was investigate environmentally and presence of al impedance s data according /electrolyte inte to depend on t istidine, phenyla ncy. The corrosio cids. The mecha ino acid molecul mic polarization rons from the al and the form , the metal acts er is in the inh mpounds have b bitors for the examination o m are toxic to t ese and many o h for better inh ome drugs an It is interesting ing organisms a ral researche ial of some a ch studies have green corrosion ome of amino ac roline, asparti ne, histidine, p sed as inhibito rode in a 0.5 M n inhibition effic onal electroch polarization tec roscopy (EIS) served ‐ Printed y ome amin d in stagnant n y safe corrosion f the corrosion in spectroscopy. T to a proposed rface under diff the adsorption o alanine and argi on inhibition effi anism of the cor les on the active n indicated that organic comp mation of a coord s as an electrop ibitor. Literatu been successful corrosion of m of these compo the environmen other factors ha hibitors. Possib nd other natu g to note that a and are precurs rs have inv amino acids an e given some ho n inhibitors [29 cids as glycine, ic acid, lysine phenyl alanine rs to control th M NaCl solution. ciency were cal hemical techni chniques and e were used. d in the USA no acids naturally aerate n inhibitors. Th nhibitor using th The experiment electronic circu ferent condition of the amino ac inine have show iciency was foun rrosion inhibitio e sites of the met the inhibitors a pounds to the dinate covalent phile while the re reveals that lly investigated metals [24,25]. ounds indicates nt while others ave prompted a bilities include ural occurring amino acids are sors for protein vestigated the nd the results ope for the use ‐31]. valine, leucine, e, methionine, e and arginine he corrosion of . The corrosion lculated. In this iques such as electrochemical Fitting of the ed he he tal uit ns. cid wn nd on tal re e t e t d . s s a e g e n e s e , , e f n s s l e experimenta to equivalen corrosion in suitable mod the alloy/sol 2. Experime The inhib from Sigma‐ in the form o appropriate area of 0.2 electrode e electrode an The chemica 0.26 Si, 0.0.2 The workin polishing wit rubbing with distilled wat measuremen neutral 0.5 M acids. The measuremen workstation. referred to 0.245 V the s potential wa until the po potential wa potentiodyna 10 mV/s. T corrosion cu potentiodyna ments, excit frequency ra inhibition ef calculated fr The experi experiment reproducibil 3. Results an 3.1. Potentio The elec investigated experiments used. The electrode we in 0.5 M sod and 25 °C. In mM of the d the potentio presence of polarization in these figu potential, E corrosion rat acid containi 1. It is clear the presence This is also cases a decre means that b decreased in general shift the ßa and ß addition of in al impedance d nt circuit mod nhibition mech del that explain lution interface ental bitor molecules Aldrich. The ca of cylindrical ro diameter by e cm2 to contac lectrochemical d saturated cal al composition 2 S, 0.04 P, 0.01 ng electrode th successive g h a smooth po ter, and then q nts were carried M NaCl solution potentiodynam nts were perf . The potenti the saturated standard hydro as left in the ele tential change as taken as th amic experimen The values of t urrent density, amic polarizat tation amplitud ange from 0.1 t fficiency, η, and rom the values mental result was carried o ity was attained nd discussion odynamic pola ctrochemical b by the polariza and Tafel e potentiodynam ere recorded af dium chloride s n these experim ifferent amino odynamic pola f different am curve in amino ures. The corro Ecorr, corrosion te of the carbon ing solutions ar from the poten e of the amino reflected on th ease in these va both the cathod n the presence t of the open‐ci ßb values and nhibitors espec El‐Sayed ata to theoreti dels enables un hanism and the ns the electroc under differen s used in this pa arbon steel elec od and mounte epoxy resin lea ct the solution. cell, with a lomel reference of carbon steel Cu, 0.01 Cr, 0.0 was pretreat grade‐emery pa olishing cloth, quickly transfe d out in stagna n free or contain mic polarizatio formed using als were mea calomel refere ogen electrode, ectrolyte to ach did not excee he steady state nts were condu the corrosion icorr, were ext tion curves. Fo de of 10 mV to 105 Hz was d the degree of of the corrosio ts were repr out at least tw d. rization measu behavior of th ation technique xtrapolation m mic polarizati fter 60 min of e solutions at a s ments a constant acids was used arization curve mino acids. Fo o acid free solu osion paramete n current den n steel in amino re calculated an ntiodynamic da acid decreases he values of bot alues was recor dic and anodic of the amino ircuit potential the current d cially for phenyl / European Jour cal values acco nderstanding o e suggestion o chemical behav nt conditions. aper were purc ctrode was pre ed into glass tub aving a free su . An all glass t a platinum co e electrode was l is: 0.34 C, 0.9 02 Ni and balan ted by mech pers up to 200 washing with erred to the ce ant, naturally ae ning 10 mM of a on and impe an electroche asured against ence electrode SHE). The elec ieve the steady ed 0.1 mV/min e potential, Ess ucted at a scan r potential, Ecorr trapolated from or all EIS mea peak‐to‐peak i used. The corr f adsorption, θ, on current den roduced and wice where a urements e carbon stee e. Linear polariz measurements on curves o electrode imme can rate of 10 t concentration d. Figures 1 pre es obtained in or comparison ution was intro ers i.e. the corr nsity, icorr, and o acid free and a nd presented in ata and Figure s the corrosion th ßa and ßb in rded (Table 1), w reaction rates acid molecules and the decre density icorr wit lalanine and arg rnal of Chemistry ording of the of the vior of chased epared bes of urface three‐ ounter s used. 93 Mn, nce Fe. anical 0 grit, triple ell. All erated amino dance emical t and (Eo = ctrode y state n. This s. The rate of r, and m the asure‐ in the rosion , were nsities. each good l was zation were f the ersion mV/s n of 10 esents n the n, the duced rosion d the amino Table 2 that n rate. n most which were s. The ase of th the ginine (Fig ano oxy inh par in T diff sug met not ami inh corr in th Figu of e solu 10 m y 7 (1) (2016) 14 gure 2). This du odic dissolution ygen reaction. ibitor on the a rameters, evalua Table 1. From ferent polarizat ggests that the tal dissolution m t change signi inoacids acts as ibition efficienc rosion current he presence of ure 1. Potentiodyn electrode immersi utions of pH = 7 us mmol/dm3 and 25 ° 4‐18 ue to that, the n of metal an This effect is ctive centers o ated from Tafel Figure 1, we c tion curves nea inhibitor mole mechanism. In ficantly in the s a mixed type cy, η, was calcu density withou the inhibitor, ic 100 namic polarization ion in 0.5 M chl ing different amin °C. addition of inh nd also retard s due to the f steel surface. l polarization cu can see that th arly the same. ecules have no addition, the va e presence of inhibitor [32]. ulated from the ut inhibitor, icor corr (inh), accord n curves of carbon loride, stagnant, no acids at constan 15 hibitor reduces s evolution of adsorption of The corrosion urves are listed he shape of the This behavior o effect on the alues of Ecorr do f inhibitor. So, . The corrosion e values of the rr, and its value ding to: (1) steel after 60 min naturally aerated nt concentration of s f f n d e r e o , n e e n d f 16 Table 1. The co acids at 25 °C. T Concentration (mM/L) Blank 0.5 M Glycine Valine Leucine Cysteine Methionine Histidine Threonine Phenyl alanine Lysine Proline Aspartic acid Arginine Glutamic acid Figure 2. Effect mmol/dm3 on aerated 0.5 M c It is clea 3 that the inh amino acid. phenyl in th its corrosion corrosion in (0.01 mol/d more than 8 increased ca alloy surface surface cove alloy surfac containing b histidine hav delocalized π its adsorptio efficiency of is well know on metallic oxygen or su N < S < P molecular st inhibition ef the possibilit atom of the process is ba on the active on the alloy steel surface interaction b atoms in am iron atoms. T it is clear tha unfilled orbi molecular o orrosion paramete The surface covera n icorr (μA/ 229.3 219.0 216.7 171.5 96.8 128.6 47.5 48.7 27.6 179.4 166.5 133.4 33.1 182.3 t of the different a the corrosion ra chloride solutions o r from the valu hibition efficien The presence o e backbone of n inhibition ca nhibition efficie dm3) of pheny 80%. Such high apability of the e by different f erage which pre ce and the c benzene ring lik ve higher effici π‐electrons of t on on the me cysteine is due wn that organic surfaces thro ulfur. The inhibi [33‐35]. The p tructure of cys fficiency. The S ty to be an ads e amino grou ased on the adso e sites and/or d surface [36]. Th e in 0.5 M NaC between the u inoacids struct The electron co at, 3d orbit wa ital of iron cou rbital of amino ers of the carbon s age and inhibition e /cm2) Ecorr (mV/SC 3 ‐882.5 0 ‐900.7 7 ‐914.3 5 ‐878.6 ‐892.3 6 ‐911.9 ‐920.5 ‐909.7 ‐918.9 4 ‐912.7 5 ‐882.0 4 ‐853.1 ‐843.1 3 ‐871.3 amino acids at cons ate of carbon stee of pH = 7 at 25 °C. ues presented in ncy depends on of functional gr the amino acid apability. There ency for such a ylalanine and a h inhibition effi e molecule to functional grou events the inte corrosive med ke phenyl alani iency that can the aromatic sy tallic surface. e to the presenc c corrosion inh ough hetero‐at iting effect follo presence of th stine provokes SH group is mo sorption center up [23]. The c orption of the a deposition of th he adsorption o Cl solution may unshared elect ure as O, N, and onfiguration of i s not fully filled uld bond with t o acids while El‐Sayed / Euro teel corrosion in s efficiency are also CE) ßa (mV/dec) 239.8 92.4 80.7 75.9 94.7 127.7 203.6 243.9 119.4 136.2 158.8 137.8 156.4 86.1 stant concentratio el in stagnant, na n Table 1 and F n the structure roups like OH, d molecule incr efore, the calcu a low concentr arginine appro iciency is due t be adsorbed o ups leading to h eraction betwee dium. Amino ine or hetero r be attributed t ystem, which en The high inhi ce of the SH gro ibitors are ads toms like nitr ows the sequen he ‐SH group i s an increase o ore donor and r beside the nit corrosion inhi amino acid mole e corrosion pro of aminoacids o y be achieved b ron pairs of h d S with d‐orbit iron was [Ar] 4 d with electron the highest occ the filled 4s o opean Journal of stagnant naturally presented. ßc (mV/dec) ‐134.5 ‐67.7 ‐62.3 ‐59.8 ‐74.5 ‐93.7 ‐112.7 ‐112.6 ‐77.4 ‐85.8 ‐103.6 ‐104.3 ‐116.8 ‐68.8 on of 10 aturally Figure of the SH or reases ulated ration oaches to the on the higher en the acids ing as to the nables bition oup. It orbed rogen, ce O < in the of the offers trogen bition ecules oducts on the by the hetero tals of 4s23d6, n. This cupied orbital cou the Figu the c aera cons allo [38 allo cati is a con at t sho mV iron sur nin pos rep Fe 3 F mor (ma stee app cur infl as i f Chemistry 7 (1) aerated neutral 0. Corrosion rate mm/y 2.700 2.590 2.560 2.030 1.185 1.574 0.582 0.596 0.339 2.197 2.040 1.633 0.405 2.157 uld interact with inhibitor [37]. ure 3. Variation of carbon steel after ated 0.5 M chlorid stant concentration It is well know oys in neutral ]. On the other oys is the dissol ions [39]. It has accelerated by t nsumption of th the cathodic on ows a passive p V vs. Ag/AgCl as n oxides and/ face. Oh et al. [4 e different oxi ssible oxides th resented accor + O2 + H2O → Fe(OH)2+ O2 → The formed fe re oxygen to fo agnetite). The p el surface from pearance of a p rent behavior. uence of chlori indicated by th (2016) 14‐18 5 M NaCl solution θ ‐ 0.044 0.054 0.252 0.578 0.439 0.792 0.788 0.879 0.218 0.274 0.418 0.855 0.209 h the lowest un f the inhibition eff 60 min of electro de solutions of pH n of 10 mmol/dm3 w that the cath solution is pri r hand, the ano lution to ferrou s been reported the presence of he produced ele ne. Figure 1 de potential region s a result of the /or corrosion 43] has reporte ide phases on hat might form ding the follow Fe(OH)2 → Fe3O4 + 3 H2O errous hydroxi orm the top laye presence of suc further dissolu passive region o The passive ide ions attack he rapid increa free and containin Surface area (cm2) ‐ 0.01 0.01 0.50 0.12 0.09 0.16 0.16 0.18 0.04 0.05 0.08 0.17 0.04 noccupied mole ficiency and the su de immersion in s = 7 using differe 3 and at 25 °C. hodic reaction imarily the oxy odic reaction f us cations and fu d [39‐42] that t f oxygen due to ectrons by the a epicts that the n between ‐800 e formation of p products on ed that iron can its surface; in m at these con wing reactions [4 de, Equation ( er of corrosion ch oxide partial utions and lead on the polariza region dissolv k and pitting co ases in the curr ng different amino η (%) ‐ 4.0 5.4 25.2 57.8 43.9 79.2 78.8 87.9 21.8 27.4 41.8 85.5 20.9 ecular orbital of urface coverage of stagnant, naturally ent amino acids at for metals and ygen reduction for iron and its further to ferric this dissolution o the increased anodic reaction steel electrode 0 mV and ‐600 passive layer of the electrode n develop up to n this case the nditions can be 40]; (2) (3) 2), reacts with product, Fe3O4 lly protects the s in turn to the ation potential‐ ves under the orrosion occurs rent values for o f f y t d n s c n d n e 0 f e o e e h 4 e e ‐ e s r steel with in acids the effe 3.2. Electroc investigatio The resu ments were studying cor the electrod generally dis plane) or Bo impedance p equally repr parameter t 47]. The tech impedance d role out mec numerical v chemical pr investigation The EIS the different carbon steel plots of the solutions an amino acids maximum a acquires low indicates the Nyquist plot and inhibited increases aft indicating th impedance d the electroc formula was 1) is introdu capacitive be factors and [46,48‐51]. where f is th The exp theoretical v model consi electrode cap resistance, R ohmic drop parameters w a constant co At a concent corrosion re results of th the four prom for the carbo the order: ph 3.3. Surface SEM pro This helps to absence and of carbon st before and a for 5 h in th shown in Fig absence of ncreasing pote ect of chloride i chemical imped ns, EIS ults of the pot confirmed by rrosion mechan de/electrolyte splayed either i de plots. Bode p plots, since all resented and to interfacial p hnique enables data to pure el chanistic model values corresp roperties of th n [46,48,49]. technique was t amino acids l in the chlorid e carbon stee d in solutions are presented at the interme wer values in the e presence of p s shows single d solutions and ter addition of hat, the corros data were analy chemical work used. In this fo uced to accoun ehavior due to adsorption eff e frequency in H perimental imp values accordi isting of a para pacitance, Cdl, a Rct, in series w p in the elec were calculated oncentration o tration of 10 mM sistance. This r he potentiodyn mising amino a on steel in 0.5 M henyl alanine > morphology by ovides a pictor o understand th presence of inh teel. The SEM after immersion he absence and gure 5. The mor inhibitor (Figu El‐Sayed ential. But, the on decreases. dance spectros tentiodynamic EIS. This techn nisms and adsor interface [44 in the form of N plots are recom experimental the phase an henomena, app the simulation lectronic mode s and enables a ponding to th he electrochem applied to inv on the corros de free neutral el electrodes i containing 10 d in Figure 4. In ediate frequen e presence of th passivation phe capacitive loop d the diameter o inhibitor to th ion inhibition yzed using soft k‐station, whe ormula an empi nt for the devia surface inhomo fects as presen Hz. pedance result ng to a simpl allel combinati and the charge ith a resistor, ctrolyte (Figur d for the investi f 10 mM and p M phenyl alanin result is in good namic experime acids 10 mM, as M sodium chlori arginine > histi y SEM rial representa he nature of th hibitors and th images of car n in 0.5 M sodiu d presence of i rphology of spe ure 5b) shows / European Jour presence of a scopic polarization e nique is power rption phenom 4]. EIS spectra Nyquist (i.e. com mmended as sta impedance dat ngle, as a sen pears explicitly n of the experim ls that can ver also the calculat he physical a mical system vestigate the eff sion behavior o solutions. The in amino acid mM of the dif n general, the ncies broadens he amino acid, w enomenon [50 p, both in uninh of the capacitive he corrosive me of steel. The w tware provided ere the dispe rical factor α (0 ation from the ogeneties, roug nted in Equatio ts were fitted le equivalent c ion representin transfer (corro Rs, representin re 4d). The igated amino ac presented in Ta ne shows the h d agreement wi ents. The ranki s corrosion inhi ide solutions, fo idine > cysteine ation of the su he surface film e extent of corr rbon steel spe um chloride so inhibitor system ecimen surface that, a very rnal of Chemistry amino xperi‐ rful in ena at a are mplex ndard ta are nsitive y [45‐ mental rify or tion of nd/or under fect of of the Bode d free fferent phase s and which ]. The hibited e loop edium whole d with ersion 0 ≤ α ≤ e ideal ghness on (4) (4) to a circuit ng the osion) ng the fitting cids at able 2. ighest ith the ing of bitors ollows e. urface. in the rosion cimen lution m are in the rough sur met pre sup film con Figu imm usin 25 ° stee = 7 c char 4. C The by usin y 7 (1) (2016) 14 face was obse tal in the cor sence of the i ppressed, due t m of the inhibi ntrols the dissol ure 4. (a‐c) Bode p mersion in stagnant ng different amino C. (d) Equivalent c l immersed in stag containing differen rge transfer (corro Conclusion e corrosion inhi amino acids as ng electrochem 4‐18 rved due to r rrosive solutio inhibitor (Figu to the formatio tor on the me lution of carbon plots of carbon stee t, naturally aerated acids at constant c circuit model for im gnant, naturally aer nt amino acids at 2 sion) resistance, C ibition of carbo s an eco‐friend mical techniques apid corrosion on. On the co re 5c), the ro on of an adsor etal surface wh n steel [42,52]. el after 60 min of e d 0.5 M chloride so concentration of 10 mpedance data fitti rated 0.5 M chlorid 5 °C. Rs= solution r Cdl= electrode capac on steel in 0.5 M ly inhibitor ha s and SEM analy 17 n attack of the ntrary, in the ugh surface is rbed protective hich effectively (a) (b) (c) (d) electrode olutions of pH = 7 0 mmol/dm3 and ing of the carbon de solutions of pH resistance, Rct= citance. M NaCl solution s been studied ysis. e e s e y n d 18 Table 2. The fi stagnant natura 10 mM/L of dif Inhibitors Blank 0.5 M Glycine Valine Leucine Cysteine Methionine Histidine Threonine Phenyl alanine Lysine Proline Aspartic acid Arginine Glutamic acid Figure 5. The s immersion (b) phenylalanine. The inh structure of hetero atoms a significan mechanism o adsorption o the alloy su polarization inhibitor. Re are in good a References [1]. Al‐Khara 32, 1363 [2]. Aramak [3]. Galvele, itting impedance p ally aerated neutr fferent amino acids Rs (Ω) 2.3 2.4 2.7 2.8 2.4 2.3 11.7 14.7 11.4 2.0 2.0 2.3 10.7 2.2 surface morpholog in chloride solu hibition efficie amino acid. T s such as sulfur nt increase in of the corrosion of the amino ac urface. Results indicated tha sults obtained agreement. afi, F. M.; Atea, B. G 3‐1370. i, K.; Shinura, T. Co J. R. Corros. Sci. 19 parameters of the ral 0.5 M NaCl solu s at 25 °C. Rct (Ω cm2) 13.4 13.8 8.9 13.4 22.7 55.6 71.5 72.2 139.8 32.5 23.7 24.0 119.9 10.5 gy of polished sam utions and (c) in ency depends The presence o r in the amino a n the inhibiti n inhibition pro cid molecules o s obtained fro at the inhibito from all electro G.; AbdAlla, R. M. J. orros. Sci. 2006, 48 981, 21, 551‐579. El‐Sayed / Euro carbon steel elect ution free and con Cdl (µF/cm2) 375.7 1153.0 296.2 592.7 175.3 2860 35.2 139.2 113.7 979.9 1061.0 331.9 132.6 303.1 (a) (b) (c) mples before (a) an presence of 10 on the che of aromatic rin acid structure c ion efficiency. ocess is based o on the active si om potentiody ors are mixed ochemical techn Appl. Electrochem 8, 209‐225. opean Journal of rode in ntaining nd after mM of emical g and causes . The on the ites of namic d‐type niques m. 2002, [4]. [5]. [6]. [7]. [8]. [9]. [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] f Chemistry 7 (1) Bockris, J. O. M. Bentiss, F.; Trai Bouklah, M.; H Electrochem. 20 Elkadi, L.; Mern 2000, 42, 703‐7 Wang, H. L.; Liu Mahmoud, S. S. . Fouda, A. S.; Electrochem. Sc . Villamizar, W.; Electrochem. 20 . Fiala, A.; Chiban Sci. 2007, 253, . Fouda, A. 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