Review Article Anodic Materials for Electrocatalytic Ozone ...can be realized by water oxidation without acid electrolyte. Stucki et al. developed the ozone generation on PbO 2 anode

Hindawi Publishing CorporationInternational Journal of ElectrochemistryVolume 2013 Article ID 128248 7 pageshttpdxdoiorg1011552013128248

Review ArticleAnodic Materials for Electrocatalytic Ozone Generation

Yun-Hai Wang and Qing-Yun Chen

State Key Laboratory of Multiphase Flow in Power Engineering Xirsquoan Jiaotong University Xirsquoan 710049 China

Correspondence should be addressed to Yun-Hai Wang wangyunhaimailxjtueducn

Received 19 March 2013 Accepted 19 May 2013

Academic Editor Shen-Ming Chen

Copyright copy 2013 Y-H Wang and Q-Y Chen This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Ozone has wide applications in various fields Electrocatalytic ozone generation technology as an alternative method to produceozone is attractive Anodic materials have significant effect on the ozone generation efficiency The research progress on anodicmaterials for electrocatalytic ozone generation including the cell configuration andmechanism is addressed in this reviewThe leaddioxide and nickel-antimony-doped tin dioxide anode materials are introduced in detail including their structure property andpreparation Advantages and disadvantages of different anode materials are also discussed

1 Introduction

Ozone is one of the most powerful oxidants currently avail-able [1 2] and it has an oxidation potential of 207V Due toits potent oxidative property ozone has been recognized asa useful chemical in disinfection and sterilization processesIt kills microorganisms decomposes organic molecules andremoves cyanide phenols manganese detergents and col-oration from aqueous systems It is used to disinfect portablewater food and surgical equipment and to treat sewagewaterswimming pool and so forth It may also be employed as araw material in the manufacture of certain organic com-pounds such as oleic acid and peroxyacetic acid [3] The useof ozone for the purification of water is particularly advanta-geous as it does not leave any harmful residuals in water [3]But ozone is unstable and its half lifetime is only about 30minin water Thus it is commonly used by on-site productiontechnology

Traditional ozone productionmethod is corona dischargeto air or pure oxygenwith the following reaction occurred [3]

3

2O2997888rarr O3 Δ119867

∘

298= 341 kcalmolminus1 (1)

In this method due to the high-frequency AC electricfield applied certain amount of harmful nitrogen oxideswill be produced if air is used as the gas source What ismore the ozone concentration cannot be higher than 3(by weight) Even by using pure oxygen as the gas source

the ozone gas concentration cannot reach as high as 10(by weight) The low ozone concentration may have variousdisadvantages In particular because of its low concentrationthe dissolved ozone is insufficient to treat the water andresults in low operational efficiency Additionally dry ozonefrom the discharge method takes a longer time to dissolve inwater than wet ozone from the electrolytic process To avoidthese disadvantages of discharge method more and moreattention shifted to the electrocatalytic method

The electrocatalytic ozone generation method is to oxi-dizewater to ozone on the anode It is well known thatwater ismore favorable to be oxidized to oxygen than ozone becausethe oxygen evolution occurs under a much lower anodicpotential than that for ozone evolution as shown in the fol-lowing reactions

2H2O 997888rarr O2+ 4H+ + 4eminus 119864∘ = 123V (2)

3H2O 997888rarr O3 + 6H++ 6eminus 119864∘ = 151V (3)

For electro-catalytic ozone production the formation ofadsorbed hydroxyl free radicals and adsorbed oxygen is veryimportant and the reaction steps are usually considered asreactions (4)ndash(7)

H2O 997888rarr OH∙ads +H++ eminus (4)

2OH∙ 997888rarr O2ads + 2H

++ 2eminus (5)

2 International Journal of Electrochemistry

OH∙ads +O2ads 997888rarr∙HO3ads (6)

∙HO3ads 997888rarr H+ +O

3+ eminus (7)

The current efficiency for ozone production can be influ-enced by many parameters Thus various electro-catalyticparameters were investigated to enhance the ozone evolutionwhile to retard the oxygen evolution reaction in past yearsThese included the anodic materials electrode morphologycell configurations current density electrolyte anodic poten-tial and temperature [4] Stucki et al studied the effect oftemperature current density and water flow rate on the cur-rent efficiency by using a polymer membrane as electrolyte[5] Except to themembrane electrolyte technology the ozoneevolution was usually studied in acidic solution by usingHClO

4 H2SO4 H3PO4 HBF

6 and HBF

4as electrolyte Peo-

ple may add some additives to these solutions to enhance theozone generation Foller et al studied the ozone generationon different anode materials in different acidic electrolyteunder different current densities [6 7] After the year of 2000the research group of Da Silva published several papers onstudying the effect of these parameters [8]

Among these parameters the anodicmaterial is one of themost important factors Different anodic materials showedmuch different performance toward electrolytic ozone gen-eration To achieve appreciable ozone evolution with con-siderable efficiency the anodic materials must be carefullychosen Thus the materials for electrolytic ozone generationmust have a high over potential for oxygen evolution toprohibit the oxygen evolution and be stable to strong anodicpolarization in the electrolyte [6] Several anode materialshave been explored including Pt DSA Au Pd PbO

2 SnO2

diamond and glassy carbon Till now only Pt lead dioxideand antimony-doped tin dioxide electrode was relativelywidely investigated for their considerable current efficiencyfor ozone generation though several other types of anodematerials were also investigated in recent years

2 Anodic Materials forElectrolytic Ozone Generation

21 Electrolytic Ozone Generation on Pt Since Schonbeindiscovered that ozone could be liberated when electrolyzingaqueous acid and salt solutions in 1840 platinum had tradi-tionally been used in ozone evolution studies The oxygenevolution overvoltage on pure bright platinum is amongthe highest observed and is the highest of the noble metalsand their alloys [9] As reported by Seader and Tobias [10]many researchers had involved in electro-catalytic ozonegeneration onPt in earlier years and theywere SoretMcLeodTargetti Grafenberg Wartenberg and Archibald MalquoriBriner and coworkers Putnam and coworkers and Lash andcoworkers

However the abovementioned research always employedconcentrated sulfuric acid or perchloric acid as supportingelectrolyte at very low temperature and under extremely highcurrent density The temperature usually ranged betweenminus14∘C and minus64∘C and the current density was usually several

tens of amperes per square centimeter In these configu-rations due to the high current density applied the heatgenerated on the electrode was very large and thus thecooling system had great influence on ozone generationefficiency They believed that the heat transfer rate andmode of electrolytic gas evolution were the critical factorsto affect the efficiency of ozone generation because of ozonedecomposition and enhanced oxygen evolution on the anodeat a higher temperature From Seader and Tobiasrsquo report [10]the lower the temperature used is the higher efficiency wouldbe achieved Under the temperature of 0∘C the efficiencydecreased sharply to not more than 1 on Pt anode

Even Pt is used at current density of tens of amperesper square centimeter for ozone generation the electrode isstable and experiences only minimal weight loss Researchinvolving the electrolytic ozone production on Pt was limitedin later time due to the high cost including electrodematerialsand operating cost related to this technology From the late1950s to the early 1970s few reports about electrolytic ozonegeneration on Pt anode were published before efficient anodematerials were discovered From the late 1970s due to theincreasing interest in the use of ozone as an alternative inwater and waste treatment several groups reopened theresearch on electrolytic ozone generation on lead dioxideanode and other anode materials

22 Electrolytic Ozone Generation on PbO2 Use of PbO

2as

anodic material for the evolution of ozone was a significantprogress for electrochemical ozone production technologyDue to its lower cost supporting high current density withoutconsiderable wear and higher current efficiency comparedwith Pt as anode under the same electrolysis condition itreplaced Pt quickly and no more investigations on Pt werepublished since the discovery of its application for electrolyticozone production

Lead dioxide has two major polymorphs alpha and betawhich occur naturally as rare minerals scrutinyite and platt-nerite respectively The alpha form has orthorhombic sym-metry with lattice constants 119886 = 0497 nm 119887 = 0596 nm119888 = 0544 nm and 119885 = 4 (four formula units per unit cell)while the symmetry of the beta form is tetragonal with latticeconstants 119886 = 0491 nm 119888 = 03385 nm and 119885 = 2The beta form is usually believed to be favorable for ozoneevolution The beta form lead dioxide was usually preparedby anodic deposition method which employed an anodiccurrent through the electrodepositing cell with lead(II) saltas electrolyte

From 1970s PbO2as anode materials for ozone genera-

tion was systematically studied by several groups [6 11 12]Firstly in order to improve the ozone generation efficiencythey follow the experience for Pt anode by using a lowertemperature and high concentrated acid as electrolyte Thetemperature could be as low as minus12∘C and the acid concentra-tion could reach up to 70Thiswould inevitably increase thetechniquersquos total cost though it was already much lower thanthat using PtThus people had to further investigate new cellconfigurations and modifications of lead dioxide to reducethe cost

International Journal of Electrochemistry 3

PEM

AnodeCathode

H+

H+

H+

H2

H2O

O3+H+

eminus

Figure 1 Schematic drawing of the new cell configuration withoutacid electrolyte

Since the early 1980s Foller and Tobias systematicallystudied ozone generation on PbO

2and made considerable

progress in this technologyThey investigated the influence ofdifferent electrolytes and the addition of several different flu-oroanions to the electrolyte (eg Fminus BF4

minus BF6minus)The highest

ozone current efficiency could reach over 50 on beta-PbO2

at 0∘Cwith a current density of about 04ndash06A cmminus2 in 73MHBF6[6] The addition of fluoroanions to the electrolyte was

believed to modify the adsorption of hydroxyl free radicalsand oxygenmolecules on the lead dioxide surface to enhancethe ozone formation The fundamental study also gave acorrelation between anion surface absorption and the currentefficiency for ozone generation [11] But the fluoroanions aregenerally toxic to human beings and harmful to the environ-ment

With the increasing attention in the electrolytic ozonegeneration technology more and more research groupsinvolved in developing this technology under relatively mildexperimental conditions by employing new electrolytic cellconfigurations and anode modifications In order to over-come the shortage of acid electrolyte corrosion duringelectro-catalytic ozone generation people developed new cellconfiguration as schematically shown in Figure 1

In this configuration the proton exchange membrane(PEM) was employed and the electrodes can be hot-pressedtogether with the PEM During electrolysis water was oxi-dized on anode to form ozone and release protonsThe gener-ated protons were then transferred to cathode through PEMand reduced to hydrogen on cathodeThus ozone productioncan be realized by water oxidation without acid electrolyteStucki et al developed the ozone generation on PbO

2anode

in pure water by using the cell configuration illustrated inFigure 1 [5 13] As reported by Stucki et al by using protonexchange membrane the anode corrosion can be effectivelyprohibited After a 2500 hour-operation the anode did notshow any degradation The maximum efficiency of 20 wasachieved at room temperature with a current density of about1 A cmminus2 Onda et al developed a multilayer electrode toimprove the cell performance for ozone generation By usinga four-layer electrode the efficiency could be improved by40 compared to a single-layer electrode [14]

Katoh et al further modified the cell design by using oxy-gen reduction replacing hydrogen evolution on cathodeThisdesign could reduce the energy consumption efficiently [15]because the oxygen reduction potential (123V as shown inreaction (2)) is much higher than that for protons reduction(00V as shown in reaction (8)) Tatapudi and Fenton [1617] directly applied PbO

2powder to the proton exchange

membrane and achieved a current efficiency of 55 forozone at room temperature with PbO

2loading of 72mg cmminus2

while hydrogen peroxide was produced on cathodeThis alsohad the potential to reduce the energy consumption becauseoxygen reduction to hydrogen peroxide (shown in reaction(9)) was easier than protons reduction to hydrogen too Thiscell configuration modification not only reduced the energyconsumption but also eliminated the explosion of hydrogenor harvested hydrogen peroxide

2H+ + 2eminus 997888rarr H2119864∘= 00V (8)

O2+ 2H+ + 2eminus 997888rarr H

2O2119864∘= 068V (9)

In addition to the above-mentioned cell configurationinvestigations many groups contributed to the anode prepa-ration to improve the ozone production efficiency Shepelinet al lengthened the working life considerably by employinga new lead dioxide design [18] Graves et al deposited thePbO2onto a porous titanium ceramic and the anode is highly

stable for electrolytic ozone generation [19] Wen and Changstudied the PbO

2structure changes during ozone evolution

and proposed that the phosphate buffer electrolyte was moreappropriate for ozone evolution [20] people also studiedthe ozone generation on PbO

2and developed new dopants

such as Fminus Fe3+ Co2+ and Ni2+ to the PbO2to improve

the efficiency and the stability for ozone generation [21ndash31]Feng et al also studied the effect of Fe doping for ozonegeneration and the efficiency increased from 61 to 146 byadding Fe dopant in the deposition solution [32] Wang andJing investigated the effect of lead dioxide particles size onozone generation performance and found that the optimizedparticles size ranged 15ndash35 um They also tried to control theparticle size by adding pore-forming agent [33] Zhou et alcompared alpha-PbO

2and beta-PbO

2anode materials for

ozone generation in water and achieved a current efficiencyof 20 [34]

Besides the cell configurations and anode preparationseveral groups investigated the mechanisms and kineticsfor ozone generation Wabner et al [35ndash37] studied themechanisms for ozone generation onPbO

2bymonitoring the

reactive intermediates and isotope marker Da Silva et al [48 38] also gave fundamental studies on ozone generation onPbO2since the year of 2000 By carefully studying the ozone

generation in different electrolytes with different extensiveand intensive parameters they proposed the mechanism forozone generation in detail The proposed mechanism wassimilar to that mentioned in reactions (4)ndash(7) Chernik et alstudied ozone generation on PbO

2in different electrolytes

and the kinetics by cyclic voltammograms [39ndash41] whileOta et al also investigated ozone generation in different acidelectrolytes [42ndash45]


Though PbO2showed considerable efficiency for ozone

generation due to its possible leakage of toxic lead ion tothe aqueous phase nonlead contained new anode materialswith higher efficiency for ozone generation should be furtherinvestigated

23 Electrolytic Ozone Generation on Doped Tin DioxideElectrode Tin dioxide is awell-knownn-type semiconductorwith a wide band gap (gt37 eV) It crystallizes with therutile structure also called cassiterite structure It is usuallyprepared by thermal decomposition method in which tinsalt can be oxidized to tin oxide in air at high temperatureTin dioxide as anode due to its high oxygen evolutionpotentialmay inhibit the thermal dynamic favorable reactionfor oxygen evolution Using tin dioxide as anode material forelectrolytic ozone generation was firstly mentioned by FollerandTobias and it was considered as unsuitable anodematerialat that time [6] Since then there were no more reports ontin dioxide as anode for electrolytic ozone generation untilthe promising results for ozone generation were publishedin 2004 by Cheng and Chan They invented a novel Sb-doped tin dioxide coated on Ti electrode which showedcurrent efficiency as high as 15 in 01M HClO

4solution at

room temperature [46] Later it was found by Chanrsquos groupthat the high efficiency for ozone generation on Sb-dopedtin dioxide electrode was possibly due to trace amount ofnickel contamination during the electrode preparation and byadding only 02 nickel (at to Sn) to the coating solutionto prepare nickel and antimony-doped tin oxide electrode(NATO) the current efficiency for ozone could reach 36 atroom temperature [47] This singular observation was laterconfirmed by several other groups [48ndash50]This novel NATOanode also showed good performance for electro-catalyticoxidation of toxic organics [51 52] The mechanism for theenhancement of ozone generation via trace nickel dopingseemed interesting and people made efforts to clarify the roleof nickel via characterizing the NATO morphology crystalstructure electrochemical properties and so forth [53 54]It was well known that Sb(V) functioned as electron donorsin tin dioxide lattice while Ni(III) functioned as electronacceptors The charge compensation effect possibly arrangedthe nickel sites adjacent to antimony sites in tin dioxidelattice Thus the adsorbed oxygen molecules on nickel siteshad more chances to react with adsorbed hydroxyl freeradicals on antimony sites to form ozoneThemechanism forthe enhancement of ozone generation via trace nickel dopingwas proposed in Figure 2

TheNATOanodewas very promising for electro-catalyticozone generation with high efficiency People also seek toimprove the system performance by using PEM electrolyteto avoid acid corrosion [55] by convective flow [56] elec-trode modification [57] to further improve the efficiencyHowever the lifetime of the anode is a problem retarding itscommercialization It suffered a logarithmic decay in currentefficiency with servicing time After 270 hours electrolysisthe current efficiency decreased from 36 to lower than 7[58] Thus efforts to enhance the lifetime were neededand recently our group found that by adapting fluoride-doped tin dioxide as interlayer the lifetime of the electrode

OO

OOO NiSb

SnSn

OO

OO O

OO

O2 ads

O3+H+

+ e

nminusp+

OH∙

ads

∙HO3

Figure 2 Mechanism for ozone formation on NATO

could be lengthened to 6 times long without considerabledepress of current efficiency [59] In a recent report theinhibition of ozone generation on NATO was observed withthe presence of high concentration of dissolved ozone [60]This observation indicated that the high performance forozone generation on this anode was not sustainable presentlybut it needed further evidence to guarantee the observation

24 Electrolytic Ozone Generation on Other Anodic MaterialsActually since the discovery of PbO

2anode for ozone gener-

ation seeking other anode materials with high performancefor ozone generation was simultaneously carried on Follerand Tobias also studied some other new anode materials forozone generation except PbO

2[6] They briefly compared Pt

black SnO2 Au Pd and DSAs respectively as anodes in

5M H2SO4 The DSAs Pd Au and Pt black showed current

efficiency as low as 01 SnO2showed current efficiency

lower than 4 and the SnO2coating film was corroded

away quickly They also mentioned the possibility of carbonmaterials (pressed carbon black graphite and glassy carbon)as anode for ozone generation These carbon electrodesshowed very poor ozone yields and exhibited rapid disinte-gration along with CO

2evolution Later Foller et al studied

ozone generation on glassy carbon in fluoroboric acid andachieved much better results [61ndash63] By using 48 HBF

4as

electrolyte under 10∘C glassy carbon anode showed currentefficiency for ozone as high as 35 and it was inert at currentdensity of 04 A cmminus2 [61] However HBF

4and HBF

6are

highly toxic and corrosiveWith the increasing demand of green chemical process

investigations to find new suitable anodic materials for elec-trochemical ozone generation appeared emergent Severalresearch groups were involved in this research Katsuki et alused boron-doped diamond electrode under severe polariza-tion where the current density was 10A cmminus2 in sulfuric acidand ozone was stably generated with a current efficiency ofa few percentage at ambient temperature [64 65] Park et alalso improved the cell design by using the diamond electrodefor electrochemical ozone generation [66 67] Kraft et alemployed PEM to perform ozone generation from water


on diamond anode and a current efficiency of 48 wasachieved [68] By using boron-doped diamond electrode forozone generation Park et al achieved a considerable ozoneconcentration and proposed the electrode as a superior stableanode for ozone generation However the overvoltage forboron-doped diamond is much higher than that for PbO

2

and DSAs in the industrial current range [65] which meansthat with the same current efficiency the energy efficiencyon boron-doped diamond will be much lower Researchersdeveloped several new DSA type electrodes by using Ta

2O5-

IrO2 Nb2O5-IrO2as active layer to study electrolytic ozone

generation [69 70] Kaneda et al [71 72] also achievedconsiderable current efficiency for ozone generation bymod-ifying the Ta

2O5with Pt and coating this active layer on Ti

However this type ofDSAs showed efficiency lower than 10Themechanisms for ozone generation on different anode

materials may be different However the reaction steps (4)ndash(7) are widely accepted and it is generally considered thatthe presence of adsorbed hydroxyl free radicals and adsorbedoxygen on adjacent sites on the electrode is important forozone formation In order to improve the efficiency for ozonegeneration the anode material must have more adjacent sitesfor hydroxyl free radicals and oxygen adsorption Generallyin metal oxide (SnO

2 PbO

2 Ta2O5 and Nb

2O5) there

usually exist oxygen vacancies to provide negatively chargedsites for oxygen adsorption and adjacent metal ions sites arepositively charged for hydroxyl free radicals adsorption Ofcourse the sites concentration is only one factor to influencethe ozone formationThe adsorption ability for hydroxyl freeradicals and oxygen may also influence the efficiency forozone generation The mechanisms are relatively complexand presently most of them are proposed and lack solidevidence Further deep insight in the mechanisms is neededespecially from the point of anode materials structure andproperties

3 Conclusions

Electro-catalytic method is a promising technology for ozoneproduction which has the advantages of high gaseous ozoneconcentration high dissolving efficiency in water and noharmful NO

119883formation In the electro-catalytic method

the anodic material is one of the key factors which influ-ence the system performance greatly Till now only boron-doped diamond electrode and nickel-antimony-doped tindioxide electrode show current efficiency of over 30 undermild experimental conditions However these two types ofelectrodes also suffer from high cost or short lifetime Itseems more effort shall be made to find new anode materialsto improve the current efficiency and stability for ozonegeneration

Acknowledgments

The authors greatly appreciate the financial support fromthe Natural Science Foundation of China (21206134) andResearch Fund for the Doctoral Program of Higher Educa-tion of China (20090201120010)

References

[1] F J BeltranOzone Reaction Kinetics forWater andWasteWaterSystems Lewis Publishers Boca Raton Fla USa 2004

[2] N P Cheremisinoff Handbook of Water and wasteWater Treat-ment Technologies Butterworth-Heinemann Woburn MassUSA 2002

[3] S Han J D Kim K C Singh and R S Chaudhary ldquoElectro-chemical generation of ozone using solid polymer electrolytemdashstate of the artrdquo Indian Journal of Chemistry Section A vol 43no 8 pp 1599ndash1614 2004

[4] L M Da Silva M H P Santana and J F C Boodts ldquoElectro-chemistry and green chemical processes electrochemical ozoneproductionrdquo Quimica Nova vol 26 no 6 pp 880ndash888 2003

[5] S Stucki H Baumann H J Christen and R Kotz ldquoPerform-ance of a pressurized electrochemical ozone generatorrdquo Journalof Applied Electrochemistry vol 17 no 4 pp 773ndash778 1987

[6] P C Foller and C W Tobias ldquoThe anodic evolution of ozonerdquoJournal of the Electrochemical Society vol 129 no 3 pp 506ndash5151982

[7] P C Foller andM L Goodwin ldquoElectrochemical generation ofhigh-concentration ozone for waste treatmentrdquo Chemical Engi-neering Progress vol 81 no 3 pp 49ndash51 1985

[8] LMDa Silva L ADe Faria and J F C Boodts ldquoElectrochemi-cal ozone production influence of the supporting electrolyte onkinetics and current efficiencyrdquo Electrochimica Acta vol 48 no6 pp 699ndash700 2003

[9] M H Miles E A Klaus B P Gunn J R Locker W E Serafinand S Srinivasan ldquoThe oxygen evolution reaction on platinumiridium ruthenium and their alloys at 80∘C in acid solutionsrdquoElectrochimica Acta vol 23 no 6 pp 521ndash526 1978

[10] J D Seader and C W Tobias ldquoOzone by electrolysis of sulfuricacidrdquo IndustrialampEngineeringChemistry vol 44 pp 2207ndash22111952

[11] P C Foller and C W Tobias ldquoThe effect of electrolyte anionadsorption on current efficiencies for the evolution of ozonerdquoJournal of Physical Chemistry vol 85 no 22 pp 3238ndash32441981

[12] P C Foller and CW Tobias ldquoThemechanism of the disintegra-tion of lead dioxide anodes under conditions of ozone evolutionin strong acid electrolytesrdquo Journal of the Electrochemical Soci-ety vol 129 pp 567ndash570 1982

[13] S Stucki GTheis R Koetz HDevantay andH J Christen ldquoInsitu production of ozone in water using amembrel electrolyzerrdquoJournal of the Electrochemical Society vol 132 no 2 pp 367ndash3711985

[14] K Onda T Ohba H Kusunoki S Takezawa D Sunakawa andT Araki ldquoImproving characteristics of ozone water productionwith multilayer electrodes and operating conditions in a poly-mer electrolyte water electrolysis cellrdquo Journal of the Electro-chemical Society vol 152 no 10 pp D177ndashD183 2005

[15] M Katoh Y Nishiki and S Nakamatsu ldquoPolymer electrolyte-type electrochemical ozone generator with an oxygen cathoderdquoJournal of Applied Electrochemistry vol 24 no 6 pp 489ndash4941994

[16] P Tatapudi and J M Fenton ldquoSynthesis of ozone in a protonexchange membrane electrochemical reactorrdquo Journal of theElectrochemical Society vol 140 no 12 pp 3527ndash3530 1993

[17] P Tatapudi and J M Fenton ldquoSimultaneous synthesis ofozone and hydrogen peroxide in a proton-exchange-membraneelectrochemical reactorrdquo Journal of the Electrochemical Societyvol 141 no 5 pp 1174ndash1178 1994


[18] V A Shepelin A A Babak G F Potapova E V Kasatkin andY E Roginskaya ldquoNew lead dioxide anode design for ozoneelectrosynthesisrdquo Soviet Electrochemistry vol 26 pp 1021ndash10271990

[19] J E Graves D Pletcher R L Clarke and F CWalsh ldquoThe elec-trochemistry of Magneli phase titanium oxide ceramic elec-trodes part II ozone generation at Ebonex and Ebonexleaddioxide anodesrdquo Journal of Applied Electrochemistry vol 22 no3 pp 200ndash203 1992

[20] T Wen and C Chang ldquoStructural changes of PbO2anodes dur-

ing ozone evolutionrdquo Journal of the Electrochemical Society vol140 no 10 pp 2764ndash2770 1993

[21] A A Babak V N Fateev R Amadelli and G F PotapovaldquoOzone electrosynthesis in an electrolyzer with solid polymerelectrolyterdquoRussian Journal of Electrochemistry vol 30 pp 739ndash741 1994

[22] A A Babak R Amadelli A De Battisti and V N FateevldquoInfluence of anions on oxygenozone evolution on PbO

2spe

and PbO2Ti electrodes in neutral pH mediardquo Electrochimica

Acta vol 39 no 11-12 pp 1597ndash1602 1994[23] A B Velichenko D V Girenko S V Kovalyov A N Gnatenko

R Amadelli and F I Danilov ldquoLead dioxide electrodepositionand its application influence of fluoride and iron ionsrdquo Journalof Electroanalytical Chemistry vol 454 no 1-2 pp 203ndash2081998

[24] R Amadelli L Armelao A B Velichenko et al ldquoOxygen andozone evolution at fluoride modified lead dioxide electrodesrdquoElectrochimica Acta vol 45 no 4-5 pp 713ndash720 1999

[25] A B Velichenko D V Girenko N V Nikolenko R AmadelliE A Baranova and F I Danilov ldquoOxygen evolution on leaddioxide modified with fluorine and ironrdquo Russian Journal ofElectrochemistry vol 36 no 11 pp 1216ndash1220 2000

[26] A B Velichenko R Amadelli G L Zucchini D V Girenkoand F I Danilov ldquoElectrosynthesis and physicochemical prop-erties of Fe-doped lead dioxide electrocatalystsrdquo ElectrochimicaActa vol 45 no 25-26 pp 4341ndash4350 2000

[27] R Amadelli A De Battisti D V Girenko S V Kovalyovand A B Velichenko ldquoElectrochemical oxidation of trans-34-dihydroxycinnamic acid at PbO

2electrodes direct electrolysis

and ozone mediated reactions comparedrdquo Electrochimica Actavol 46 no 2-3 pp 341ndash347 2000

[28] R Amadelli and A B Velichenko ldquoLead dioxide electrodesfor high potential anodic processesrdquo Journal of the SerbianChemical Society vol 66 no 11-12 pp 834ndash845 2001

[29] A B Velichenko R Amadelli E A Baranova D V Girenkoand F I Danilov ldquoElectrodeposition of Co-doped lead dioxideand its physicochemical propertiesrdquo Journal of ElectroanalyticalChemistry vol 527 no 1-2 pp 56ndash64 2002

[30] A B Velichenko R Amadelli A Benedetti D V Girenko S VKovalyov and F I Danilov ldquoElectrosynthesis and physicochem-ical properties of PbO

2filmsrdquo Journal of the Electrochemical

Society vol 149 no 9 pp C445ndashC449 2002[31] R Amadelli A Maldotti A Molinari F I Danilov and A B

Velichenko ldquoInfluence of the electrode history and effects ofthe electrolyte composition and temperature on O

2evolution

at 120573-PbO2anodes in acid mediardquo Journal of Electroanalytical

Chemistry vol 534 no 1 pp 1ndash12 2002[32] J Feng D C Johnson S N Lowery and J J Carey ldquoElec-

trocatalysis of anodic oxygen-transfer reactions evolution ofozonerdquo Journal of the Electrochemical Society vol 141 no 10 pp2708ndash2711 1994

[33] J Wang and X Jing ldquoStudy on the effect of the lead dioxideparticles on the anodic electrode performance for ozone gen-erationrdquo Electrochemistry vol 74 no 7 pp 539ndash543 2006

[34] Y Zhou B Wu R Gao H Zhang and W Jiang ldquoPerformanceof PbO

2anode catalysts on solid polymer electrolyte mem-

brance electrode composite in electrolytic ozone generatorsrdquoChinese Journal of Applied Chemistry vol 13 pp 95ndash97 1996

[35] J C G Thanos and D W Wabner ldquoStructural changes ofthe texture of 120573-lead dioxide-titanium anodes during theoxygenozone electrosynthesis in neutral and acid electrolytesrdquoJournal of Electroanalytical Chemistry vol 182 no 1 pp 37ndash491985

[36] J C Thanos and D W Wabner ldquoElectrochemical-separationof oxygen and ozone on lead dioxide and platinium anodesin aqueos-electroltes with O-18 marked waterrdquo ElectrochimicaActa vol 30 pp 753ndash756 1985

[37] D Wabner and C Grambow ldquoReactive intermediates duringoxindation of water lead dioxide and platinum electrodesrdquoJournal of Electroanalytical Chemistry vol 195 no 1 pp 95ndash1081985

[38] L M Da Silva L A De Faria and J F C Boodts ldquoGreen pro-cesses for environmental application Electrochemical ozoneproductionrdquo Pure and Applied Chemistry vol 73 no 12 pp1871ndash1884 2001

[39] A A Chernik V B Drozdovich and I M Zharskii ldquoOzoneevolution at the lead dioxide electrode in highly acid andneutralelectrolytes the influence of polarization and fluoride ions onthe process kineticsrdquo Russian Journal of Electrochemistry vol33 no 3 pp 259ndash263 1997

[40] A A Chernik V B Drozdovich and I M Zharskii ldquoOzoneevolution at the lead dioxide electrode in sulfuric and perchloricacid solutionsrdquo Russian Journal of Electrochemistry vol 33 no3 pp 264ndash267 1997

[41] A A Chernik and IM Zharskii ldquoOzone generation on the leaddioxide electrodes in a sulfuric acid solution at potentials of 2 to3 Vrdquo Russian Journal of Electrochemistry vol 36 no 4 pp 387ndash391 2000

[42] KOtaH Kaida andNKamiya ldquoElectrolytic ozone generationin sulfuric acid solutionrdquo Denki Kagaku vol 54 pp 890ndash8951986

[43] KOtaH Kaida andNKamiya ldquoElectrolytic ozone generationin perchloric acid solutionrdquoDenki Kagaku vol 55 pp 465ndash4681987

[44] KOtaH Kaida andNKamiya ldquoElectrolytic ozone generationin phosphoric acid solutionrdquo Denki Kagaku vol 56 pp 206ndash207 1988

[45] KOtaH Kaida andNKamiya ldquoElectrolytic ozone generationin aqueous phosphate solutionrdquoDenki Kagaku vol 56 pp 741ndash744 1988

[46] S Cheng and K Chan ldquoElectrolytic generation of ozone on anantimony-doped tin dioxide coated electroderdquo Electrochemicaland Solid-State Letters vol 7 no 3 pp D4ndashD6 2004

[47] Y Wang S Cheng K Chan and X Y Li ldquoElectrolytic gen-eration of ozone on antimonymdashand nickel-doped tin oxideelectroderdquo Journal of the Electrochemical Society vol 152 no 11pp D197ndashD200 2005

[48] P A Christensen W F Lin H Christensen et al ldquoRoom tem-perature electrochemical generation of ozone with 50 currentefficiency in 05m sulfuric acid at cell voltages lt 3Vrdquo OzoneScience amp Engineering vol 31 no 4 pp 287ndash293 2009


[49] J Basiriparsa andM Abbasi ldquoHigh-efficiency ozone generationvia electrochemical oxidation of water using Ti anode coatedwith Ni-Sb-SnO

2rdquo Journal of Solid State Electrochemistry vol

16 no 3 pp 1011ndash1018 2012[50] H Shekarchizade andMK Amini ldquoEffect of elemental compo-

sition on the structure electrochemical properties and ozoneproduction activity of TiSnO

2-Sb-Ni electrodes prepared by

thermal pyrolysis methodrdquo International Journal of Electro-chemical vol 2011 Article ID 240837 13 pages 2011

[51] S Y Yang Y S Choo S Kim S K Lim J Lee and H ParkldquoBoosting the electrocatalytic activities of SnO

2electrodes for

remediation of aqueous pollutants by doping with various met-alsrdquo Applied Catalysis B vol 111-112 pp 317ndash325 2012

[52] Q Chen D Shi Y Zhang and Y Wang ldquoPhenol degradationon novel nickel-antimony doped tin dioxide electroderdquo WaterScience and Technology vol 62 no 9 pp 2090ndash2095 2010

[53] Y H Wang K Y Chan X Y Li and S K So ldquoElectrochemicaldegradation of 4-chlorophenol at nickel-antimony doped tinoxide electroderdquo Chemosphere vol 65 no 7 pp 1087ndash10932006

[54] P A Christensen K Zakaria and T P Curtis ldquoStructure andactivity of Ni-and Sb-doped SnO

2ozone anodesrdquo Ozone Sci-

ence amp Engineering vol 34 pp 49ndash56 2012[55] Y Wang S Cheng and K Chan ldquoSynthesis of ozone from air

via a polymer-electrolyte-membrane cell with a doped tin oxideanoderdquo Green Chemistry vol 8 no 6 pp 568ndash572 2006

[56] Y Cui YWang BWang H Zhou K Chan andX Li ldquoElectro-chemical generation of ozone in a membrane electrode assem-bly cell with convective flowrdquo Journal of the ElectrochemicalSociety vol 156 no 4 pp E75ndashE80 2009

[57] J B Parsa M Abbasi and A Cornell ldquoImprovement of thecurrent efficiency of the TiSn-Sb-Ni oxide electrode via carbonnanotubes for ozone generationrdquo Journal of the ElectrochemicalSociety vol 159 no 5 pp D265ndashD269 2012

[58] Y H Wang Electrochemical generation of ozone on antimonyand nickel doped tin oxide [PhD thesis]TheUniversity of HongKong Hong Kong July 2006

[59] G Li Y HWang and Q Y Chen ldquoInfluence of fluoride-dopedtin oxide interlayer on Ni-Sb-SnO

2Ti electrodesrdquo Journal of

Solid State Electrochemistry vol 17 no 5 pp 1303ndash1309 2013[60] P A Christensen and A Imkum ldquoThe inhibition of ozone gen-

eration at NiSb-SnO2electrodes in high concentrations of dis-

solvedO3rdquoOzone Science amp Engineering vol 33 no 5 pp 389ndash

395 2011[61] P C Foller and M L Goodwin ldquoThe electrochemical genera-

tion of high concentration ozone for small-scale applicationsrdquoOzone Science amp Engineering vol 6 no 1 pp 29ndash36 1984

[62] P C Foller and G H Kelsall ldquoOzone generation via theelectrolysis of fluoboric acid using glassy carbon anodes and airdepolarized cathodesrdquo Journal of Applied Electrochemistry vol23 no 10 pp 996ndash1010 1993

[63] P C Foller M L Goodwin and C W Tobias ldquoGlassy-carbonanodes and air-depolarized cathodes for the generation ofozonerdquo Journal of the Electrochemical Society vol 130 pp C113ndashC118 1983

[64] N Katsuki S Wakita Y Nishiki T Shimamune Y Akiba andM Iida ldquoElectrolysis by using diamond thin film electrodesrdquoJapanese Journal of Applied Physics vol 36 no 3 A pp L260ndashL263 1997

[65] N Katsuki E Takahashi M Toyoda et al ldquoWater electrolysisusing diamond thin-film electrodesrdquo Journal of the Electrochem-ical Society vol 145 no 7 pp 2358ndash2362 1998

[66] S Park ldquoStable ozone generation by using boron-doped dia-mond electrodesrdquo Russian Journal of Electrochemistry vol 39no 3 pp 321ndash322 2003

[67] S Park G Kim J Park Y Einaga and A Fujishima ldquoUse ofboron-doped diamond electrode in ozone generationrdquo Journalof New Materials for Electrochemical Systems vol 8 no 1 pp65ndash68 2005

[68] A Kraft M Stadelmann MWunsche andM Blaschke ldquoElec-trochemical ozone production using diamond anodes and asolid polymer electrolyterdquo Electrochemistry Communicationsvol 8 no 5 pp 883ndash886 2006

[69] L M Da Silva D V Franco L A De Faria and J F C BoodtsldquoSurface kinetics and electrocatalytic properties of Ti(IrO

2+

Ta2O5) electrodes prepared using controlled cooling rate for

ozone productionrdquo Electrochimica Acta vol 49 no 22-23 pp3977ndash3988 2004

[70] M H P Santana L A De Faria and J F C Boodts ldquoInves-tigation of the properties of Ti[IrO

2-Nb2O5] electrodes for

simultaneous oxygen evolution and electrochemical ozone pro-duction EOPrdquoElectrochimicaActa vol 49 no 12 pp 1925ndash19352004

[71] K Kaneda M Ikematsu M Iseki et al ldquoA novel electrode forozone generationrdquo Chemistry Letters vol 34 no 10 pp 1320ndash1321 2005

[72] K Kaneda M Ikematsu Y Koizumi et al ldquoOzone generationby a TaO

119909and Pt composite insulator-coated Ti electroderdquo

Electrochemical and Solid-State Letters vol 8 no 6 pp J13ndashJ162005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


OH∙ads +O2ads 997888rarr∙HO3ads (6)

∙HO3ads 997888rarr H+ +O

3+ eminus (7)

The current efficiency for ozone production can be influ-enced by many parameters Thus various electro-catalyticparameters were investigated to enhance the ozone evolutionwhile to retard the oxygen evolution reaction in past yearsThese included the anodic materials electrode morphologycell configurations current density electrolyte anodic poten-tial and temperature [4] Stucki et al studied the effect oftemperature current density and water flow rate on the cur-rent efficiency by using a polymer membrane as electrolyte[5] Except to themembrane electrolyte technology the ozoneevolution was usually studied in acidic solution by usingHClO

4 H2SO4 H3PO4 HBF

6 and HBF

4as electrolyte Peo-

ple may add some additives to these solutions to enhance theozone generation Foller et al studied the ozone generationon different anode materials in different acidic electrolyteunder different current densities [6 7] After the year of 2000the research group of Da Silva published several papers onstudying the effect of these parameters [8]

Among these parameters the anodicmaterial is one of themost important factors Different anodic materials showedmuch different performance toward electrolytic ozone gen-eration To achieve appreciable ozone evolution with con-siderable efficiency the anodic materials must be carefullychosen Thus the materials for electrolytic ozone generationmust have a high over potential for oxygen evolution toprohibit the oxygen evolution and be stable to strong anodicpolarization in the electrolyte [6] Several anode materialshave been explored including Pt DSA Au Pd PbO

2 SnO2

diamond and glassy carbon Till now only Pt lead dioxideand antimony-doped tin dioxide electrode was relativelywidely investigated for their considerable current efficiencyfor ozone generation though several other types of anodematerials were also investigated in recent years

2 Anodic Materials forElectrolytic Ozone Generation

21 Electrolytic Ozone Generation on Pt Since Schonbeindiscovered that ozone could be liberated when electrolyzingaqueous acid and salt solutions in 1840 platinum had tradi-tionally been used in ozone evolution studies The oxygenevolution overvoltage on pure bright platinum is amongthe highest observed and is the highest of the noble metalsand their alloys [9] As reported by Seader and Tobias [10]many researchers had involved in electro-catalytic ozonegeneration onPt in earlier years and theywere SoretMcLeodTargetti Grafenberg Wartenberg and Archibald MalquoriBriner and coworkers Putnam and coworkers and Lash andcoworkers

However the abovementioned research always employedconcentrated sulfuric acid or perchloric acid as supportingelectrolyte at very low temperature and under extremely highcurrent density The temperature usually ranged betweenminus14∘C and minus64∘C and the current density was usually several

tens of amperes per square centimeter In these configu-rations due to the high current density applied the heatgenerated on the electrode was very large and thus thecooling system had great influence on ozone generationefficiency They believed that the heat transfer rate andmode of electrolytic gas evolution were the critical factorsto affect the efficiency of ozone generation because of ozonedecomposition and enhanced oxygen evolution on the anodeat a higher temperature From Seader and Tobiasrsquo report [10]the lower the temperature used is the higher efficiency wouldbe achieved Under the temperature of 0∘C the efficiencydecreased sharply to not more than 1 on Pt anode

Even Pt is used at current density of tens of amperesper square centimeter for ozone generation the electrode isstable and experiences only minimal weight loss Researchinvolving the electrolytic ozone production on Pt was limitedin later time due to the high cost including electrodematerialsand operating cost related to this technology From the late1950s to the early 1970s few reports about electrolytic ozonegeneration on Pt anode were published before efficient anodematerials were discovered From the late 1970s due to theincreasing interest in the use of ozone as an alternative inwater and waste treatment several groups reopened theresearch on electrolytic ozone generation on lead dioxideanode and other anode materials

22 Electrolytic Ozone Generation on PbO2 Use of PbO

2as

anodic material for the evolution of ozone was a significantprogress for electrochemical ozone production technologyDue to its lower cost supporting high current density withoutconsiderable wear and higher current efficiency comparedwith Pt as anode under the same electrolysis condition itreplaced Pt quickly and no more investigations on Pt werepublished since the discovery of its application for electrolyticozone production

Lead dioxide has two major polymorphs alpha and betawhich occur naturally as rare minerals scrutinyite and platt-nerite respectively The alpha form has orthorhombic sym-metry with lattice constants 119886 = 0497 nm 119887 = 0596 nm119888 = 0544 nm and 119885 = 4 (four formula units per unit cell)while the symmetry of the beta form is tetragonal with latticeconstants 119886 = 0491 nm 119888 = 03385 nm and 119885 = 2The beta form is usually believed to be favorable for ozoneevolution The beta form lead dioxide was usually preparedby anodic deposition method which employed an anodiccurrent through the electrodepositing cell with lead(II) saltas electrolyte

From 1970s PbO2as anode materials for ozone genera-

tion was systematically studied by several groups [6 11 12]Firstly in order to improve the ozone generation efficiencythey follow the experience for Pt anode by using a lowertemperature and high concentrated acid as electrolyte Thetemperature could be as low as minus12∘C and the acid concentra-tion could reach up to 70Thiswould inevitably increase thetechniquersquos total cost though it was already much lower thanthat using PtThus people had to further investigate new cellconfigurations and modifications of lead dioxide to reducethe cost


PEM

AnodeCathode

H+

H+

H+

H2

H2O

O3+H+

eminus











2anode







2H+ + 2eminus 997888rarr H2119864∘= 00V (8)


2O2119864∘= 068V (9)








2and beta-PbO




2bymonitoring the









4solution at



OO

OOO NiSb

SnSn

OO

OO O

OO

O2 ads

O3+H+

+ e

nminusp+

OH∙

ads

∙HO3














4as


4and HBF

6are





2


2O5-






2 PbO

2 Ta2O5 and Nb

2O5) there


3 Conclusions




Acknowledgments


References

























2spe
















2evolution






























2electrodes for


























2+



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


PEM

AnodeCathode

H+

H+

H+

H2

H2O

O3+H+

eminus











2anode







2H+ + 2eminus 997888rarr H2119864∘= 00V (8)


2O2119864∘= 068V (9)








2and beta-PbO




2bymonitoring the









4solution at



OO

OOO NiSb

SnSn

OO

OO O

OO

O2 ads

O3+H+

+ e

nminusp+

OH∙

ads

∙HO3














4as


4and HBF

6are





2


2O5-






2 PbO

2 Ta2O5 and Nb

2O5) there


3 Conclusions




Acknowledgments


References

























2spe
















2evolution






























2electrodes for


























2+



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





4solution at



OO

OOO NiSb

SnSn

OO

OO O

OO

O2 ads

O3+H+

+ e

nminusp+

OH∙

ads

∙HO3














4as


4and HBF

6are





2


2O5-






2 PbO

2 Ta2O5 and Nb

2O5) there


3 Conclusions




Acknowledgments


References

























2spe
















2evolution






























2electrodes for


























2+



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



2


2O5-






2 PbO

2 Ta2O5 and Nb

2O5) there


3 Conclusions




Acknowledgments


References

























2spe
















2evolution






























2electrodes for


























2+



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of








2spe
















2evolution






























2electrodes for


























2+



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of









2electrodes for


























2+



















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Documents

Review Article Anodic Materials for Electrocatalytic Ozone ...can be realized by water oxidation without acid electrolyte. Stucki et al. developed the ozone generation on PbO 2 anode