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Enhancemen o isible ligh -induced su ace pho o-ac i i y o
nanos uc u ed N-TiO2 hin ilms modi ied by Ion Implan a ion
Pablo Rome o-Gomez,*1-2 Ca men Lopez-San os,1 Ana Bo as,1 Juan Ped o Espinos,1
Albe o Palme o,1Agus in R. Gonzalez-Elipe1
1- Ins i u o de Ciencia de Ma e iales de Se illa (CSIC, U. Se illa), C/ Amé ico Vespucio
49, E-41092 Se illa, Spain.
2- ICFO-The Ins i u e o Pho onic Sciences, Medi e anean Technology Pa k, 08860
Cas ellde els, Ba celona, Spain.
ABSTRACT
This wo k epo s he mo phological and chemical modi ica ions induced in TiO2 hin ilms by
bomba dmen wi h high ene gy N+ ions a di e en empe a u es and hei di e en pho o-ac i i y
esponses a e implan a ion unde isible and UV ligh illumina ion. When implan ed samples a e
illumina ed wi h isible ligh , no dye pho o-decolou a ion akes place despi e ha ligh ans o med
he su aces om hyd ophobic o hyd ophilic. In ag eemen wi h he Wenzel model o we ing,
co ela ion is ound be ween isible ligh pho o-ac i i y and ilm mo phology. We conclude ha he
pho o-ac i i y esponse can be sepa a ed in o shallow and Scho ky ba ie pho o-ac i i y, his la e
in ol ing a hicke laye o ma e ial.
Keywo ds
N-TiO2, ligh induced we ing, ion implan a ion, su ace pho o-ac i i y, PECVD, Wenzel model.
*Elec onic mail: pablo. o[email p o ec ed], el. +34 954 48 95 28, Ins i u o de Ciencia de Ma e iales de
Se illa (CSIC, U. Se illa), C/ Amé ico Vespucio 49, E-41092 Se illa, Spain.
*The Manusc ip
Click he e o iew linked Re e ences
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TiO2 is a well-known ma e ial because o i s wide use in nume ous applica ions such as pho o-anode
in pho o-elec ochemical cells, pho o-ca alys , anode in hyb id pho o ol aic cells o coa ing o sel -
cleaning applica ions [1-4]. Ye , TiO2 has an impo an d awback ega ding sola ene gy applica ions
as i only shows a selec i e esponse o he UV egion o he sola spec um, which only accoun s o
5% o he collec ed ligh on ea h. To add ess his p oblem, many wo ks ha e a emp ed o dope his
wide band gap semiconduc o (3.2 eV) [5] o shi i s pho o- esponse onse owa ds he isible ligh
egion [6-11]. Acco ding o Asahi e al. [6], he p esence o a small amoun o N in he TiO2 ne wo k
al e s he band gap s uc u e and igge s he pho o- esponse o he ma e ial unde isible ligh
illumina ion. A e his seminal wo k, many o he pape s ha e deal wi h his issue [12-21] inding
ha , besides composi ion and c ys allog aphic s uc u e [22], su ace mo phology could also play an
impo an ole in he pho o-ac i i y o his oxide. Howe e , expe imen al e idences on his issue a e
s ill unde discussion as hei ele ance seems o s ongly depend upon he pa icula pho o-ac i i y
es employed [23].
A ypical su ace pho o-ac i i y es conce ns he we ing beha iou o TiO2 su aces upon
illumina ion: as i was i s demons a ed by Wang e al. [3], he we ing beha iou o la TiO2
su aces e ol es om a hyd ophobic o a supe hyd ophilic s a e when samples a e illumina ed wi h
UV-ligh . Al hough his s udy was ca ied ou mo e han a decade ago, he physicochemical p ocesses
esponsible o he e e sible con e sion be ween hese wo s a es a e s ill a ma e o deba e [24-31].
Fo ins ance, in p e ious wo ks on nanos uc u ed su aces, we ha e shown ha su ace oughness o
he ni ogen doping s a e a e c i ical ac o s a ec ing bo h, he WCA o he o iginal samples be o e
illumina ion [32] and hei esponse when using isible ligh [33,34]. A i s goal o he p esen wo k
is o s udy he e ec o isible ligh illumina ion o N-doped TiO2 in an a emp o un a el he e ec
o bo h, su ace opog aphy and chemis y, on he we ing beha iou . Fo his pu pose, we ha e
conside ed he classical model o Wenzel o accoun o he in luence o su ace oughness on he
we ing con ac angle. In he cou se o his in es iga ion, we ha e ound ha he ligh -induced
hyd ophobic/supe hyd ophilic con e sion is exclusi ely linked o he chemical and mo phological
p ope ies o he ou mos su ace laye s, which en a i ely we will called shallow pho o-ac i i y, while
o he pho o-ac i i y es s, such as he pho o-ca aly ic deg ada ion o dye molecules, in ol e a
ela i ely hicke laye o su ace ma e ial wi h well-de ined TiO2 s oichiome y. Consequen ly, we
conclude ha each pho o-ac i e esponse o he ma e ial is media ed h ough di e en mechanisms
ac ing on di e en spa ial scales on he ou mos su ace laye s o he ilms.
Nanos uc u ed N-TiO2 su aces we e p epa ed in wo s eps: i s , TiO2 hin ilms we e deposi ed by
plasma enhanced chemical apou deposi ion (PECVD) a 523 K. De ails abou he mo phology,
mic os uc u e and o he cha ac e is ics o hese hin ilms, as well as he desc ip ion o he deposi ion
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echnique, ha e been epo ed p e iously [34]. Films displayed an ana ase s uc u e wi h a high
deg ee o c ys allini y and showed a clea columna mic os uc u e pe pendicula o he subs a e. In a
second s ep, ilms we e exposed o high ene gy ni ogen ions by means o a pa icle accele a o .
These ion implan a ion expe imen s we e ca ied ou wi h he high cu en ion implan e DANFYS
1090-200(DANFYSIK A/S, Jyllinge Denma k) a he Ins i u e o Ion Beam Physics and Ma e ials
Resea ch in he Fo schungszen um Rossendo , Ge many, being he maximum accele a ion ol age
o his machine 200 kV. Fo equal ion doses and impingemen angle, implan a ions we e ca ied ou a
wo di e en subs a e empe a u es. The expe imen al condi ions u ilized in each case a e
summa ized in Table I: Sample A is a es sample analysed jus a e deposi ion. Sample B ep esen s
a ilm deposi ed unde he same condi ions as sample A, expe iencing he N+ ion implan a ion
(keeping he ilm a oom empe a u e du ing he p ocedu e) a e wa ds. The ion ange wi hin he
ma e ial in hese condi ions has been es ima ed using he well-known so wa e SRIM [35], yielding a
alue o ~100 nm. Following he well-known e ec s o implan ed ions in TiO2 [36], we assume ha a
laye wi h simila hickness has been subjec ed o a conside able la ice damage esul ing in he
o ma ion o a high concen a ion o oxygen acancies, poin de ec s in he ne wo k and o he ela ed
e ec s. Fu he mo e, as an addi ional amo phiza ion o he ilm may appea along he ion acks
[37,38], we also analysed sample C, whe e he ion implan a ion condi ions we e he same as hose
employed o sample B, bu keeping he ilm empe a u e a 400 ºC h oughou he whole p ocedu e
his ime, jus o ensu e ha he ilm could ec ys allize in o he ana ase s uc u e.
Ru he o d Backsca e ing Spec oscopy (RBS) has been u ilized o assess he a om dis ibu ion
p o ile in he ilms and in hei implan ed zones. Expe imen s we e ca ied ou in a 3 MeV andem
accele a o a he CNA (Se illa, Spain) wi h a beam o 1.5−2.0 MeV alpha pa icles, accumula ed
doses abou 1.5 μC, and ∼1 mm beam spo diame e . The RBS spec a we e simula ed wi h he
SIMRNA so wa e [39]. Resul s indica e ha ni ogen ion bomba dmen caused he oxygen deple ion
in he implan ed laye : Figu e 1 shows he expe imen al and simula ed spec a o samples A, B and C.
A compa a i e assessmen o he shape o he Ti signal in Figu e 1 clea ly shows ha he implan ed
laye in Sample B (a ound 100 nm) is oxygen deple ed as indica ed by he ela i e inc ease in he
in ensi y o he Ti signal close o he su ace. A simila e ec is obse ed in sample C whe e he
a ia ion in he in ensi y o he Ti signal is smoo he . In o he wo ds, i seems ha he implan ed
zones in samples B and C p esen some oxygen deple ion esul ing om an ex ensi e o ma ion o
oxygen acancies. This esul ag ees wi h su ace conduc i i y measu emen s ca ied ou by he ou -
poin p obe es . Fo hese measu emen s a Kei hley 617 Elec ome e and a Hewle -Packa d 34401 A
ol amme e we e used o apply a ol age anging be ween -0.25 and 0.25 V o wo ex e nal p obes
and o measu e he cu en lowing be ween wo in e nal p obes. In his way, he su ace esis i i y o
he h ee samples (see Table 1) shows a comple ely di e en beha iou : sample A has a highly
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esis i e cha ac e , whe eas samples B and C show e y low esis i i y, which again ag ees wi h he
obse ed oxygen deple ion o he ne wo k la ices.
The su ace s a e o samples a e ni ogen implan a ion was assessed by X- ay Pho oelec on
Spec oscopy (XPS) eco ded on a VG ESCALAB 210 spec ome e wo king unde pass ene gy
cons an condi ions. The Mg Kα line was used o exci a ion o he spec a, calib a ed in binding
ene gy (BE) by e e encing o he C1s peak due o con amina ion aken a 284.6 eV. In all he
samples, he O(1s) and Ti(2p) spec a we e ypical o TiO2 hin ilms [40], a ea u e ha indica es ha
he ou mos su ace laye s wi hin he hickness analysed by he XPS echnique ha e become ully
oxidized due o he exposu e and handling o he ilms in he a mosphe e. In e es ingly, he XPS
measu emen s also show he exis ence o ni ogen species on he su ace o he B and C ilms. Figu e
2 shows he decon olu ion o he N1s pho oemission spec a eco ded o he h ee samples: sample A
does no con ain ni ogen, a ac ha is expec ed as i did no unde go he N+ ion implan a ion.
Samples B and C display simila spec al shapes, indica ing ha , unlike sample A hey possess N on
he ou mos su ace laye s wi h simila chemical s a e. A ough i ing analysis o hese wo spec a is
possible by assuming h ee componen s cen ed a 396.2, 398.8 and 401.2eV wi h a ea a ios o
1:0.24:0.14 and 1:0.45:0.19 o samples B and C, espec i ely. Despi e some con o e sy in he
li e a u e conce ning he assignmen o hese h ee componen s [40] a a he accep ed consensus is
ha he wide band a ound 396.2 eV is associa ed wi h diamagne ic N(III) species subs i u ing O(II)
si es. Meanwhile, he N1s peaks a a ound 398.8 and 401.2 eV ha e been assigned o in e s i ial N
species [41-43], possibly bound o la ice oxygen in a kind o NO-like uni s. The di e ence be ween
hese wo la e s a es seems o be he ype o in e s i ial cen e occupied by he ni ogen in he TiO2
s uc u e [37].
The su ace mo phology o he ilms was highly a ec ed by he ion implan a ion: Figu e 3 shows he
a omic o ce mic oscopy (AFM) images o he h ee in es iga ed samples. These images we e
collec ed in an AFM dimension 3100 om Digi al Ins umen in apping mode using high equency
le e s, and p ocessed wi h he WSxM ee a ailable so wa e om Nano ec [48]. Roughness o he
ilms, exp essed as he oo mean squa e (RMS) alue o he su ace heigh s, has been calcula ed om
he images by using his so wa e. This analysis concluded ha sample A possesses a g anula
s uc u e wi h a RMS o 1.9 nm [34], whe eas sample B (whe e he ion implan a ion ook place a
oom empe a u e) shows an almos la su ace opog aphy wi h an es ima ed alue o he RMS
a ound 0.2 nm. This is consis en wi h he ield emission scanning elec on mic oscopy (FESEM)
cha ac e iza ion o hese samples, which indica es ha hey p esen a sponge-like mic os uc u e
unde nea h, capped by a qui e la su ace [38]. Meanwhile, sample C, wi h a RMS alue o 4.7 nm, is
cha ac e ized by a il ed nano od mic os uc u e ha has been a ibu ed o he N+ implan a ion a 400
⁰C, and whose o igin was explained elsewhe e [38].
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By aking in o accoun he p e ious analysis, a easonable schema ic ep esen a ion o he
composi ion p o iles o samples A, B and C is p esen ed as inse s in Figu e 1: sample A is ully
s oichiome ic, while samples B and C p esen h ee di e en zones: i) ew su ace laye s wi h a TiO2
s oichiome y and some ni ogen species, ollowed by ii) a zone deple ed in oxygen whe e, in
ag eemen wi h p e ious s udies [38], ni ogen is mos ly in he chemical o m o ni ide species, and
iii) a hi d zone ha co esponds o he egion o he ilm no a ec ed by he N+ ions, and whose
composi ion is again s oichiome ic TiO2. Acco ding o his laye dis ibu ion, samples B and C
possess e y di e en su ace oughness bu e y simila mo phological and chemical s uc u es: he
wo ilms sha e a simila su ace composi ion (N-doped TiO2) and p esen a second laye unde nea h
deple ed in oxygen ha ex ends along he dep h whe e a Scho ky Ba ie is ypically o med.
The pho o-ac i i y o samples A-C was i s e alua ed by acking he change in he WCA upon
isible and UV ligh i adia ion. The eco e y o he WCA in da kness a e illumina ion
complemen ed hese es s. In pa allel, he pho o-ca aly ic ac i i y o hese samples was es ed by
ollowing hei capabili y o decolo ize a solu ion wi h a dye [23,33]. In he i s place, measu emen s
o wa e con ac angle (WCA) o samples A, B and C we e ca ied ou by he Young me hod by
dosing small d ople s o deionized and bidis illed wa e on he su ace o he samples illumina ed o
inc easing pe iods o ime. Du ing he expe imen s, a me al oil ac ing as a shu e was used o close
and open he lamp ou pu . The epo ed esul s co espond o samples ha we e s o ed in da k in a
desicca o , a leas o wo mon hs, be o e es ing hei pho o-ac i i y. Illumina ion o he samples was
ca ied ou wi h a Xe discha ge lamp wi h pho on in ensi y a he posi ion o he samples o 2 W cm-2
o he comple e spec um. An in a ed il e (i.e. a wa e ba h) was kep be ween he lamp and he
samples o p e en any possible hea ing by he in a ed adia ion. On he o he hand, dye deg ada ion
expe imen s unde isible and UV illumina ion we e ca ied ou in a home-made expe imen al se -up
consis ing o a small cell made o qua z ( o al olume 3 cm3) whe e 2 cm3 o a 3.5 × 10-5 M solu ion
o me hyl o ange dye was placed oge he wi h a piece o a silicon subs a e (1 × 0.8 cm2) wi h he
hin ilm deposi ed on i s su ace. The in ensi y o he UV + isible adia ion a he posi ion o he cell
was 1.8 W (i.e., app oxima ely 0.3 W cm-2 o pho ons wi h λ < 380 nm). Visible illumina ion was
ca ied ou by placing a il e (i.e., λ >380 nm) be ween he Xe discha ge lamp and he eac ion essel.
The in ensi y o he isible adia ion a he cell posi ion was 160 mW cm-2. Addi ional de ails abou
his expe imen can be ound in a p e ious publica ion [23].
The dye deg ada ion expe imen s showed ha sample A was able o decolo ize he dye solu ion upon
i adia ion wi h a ull ange lamp (i.e. emi ing in he UV and isible ange) [23], while samples B and
C did no induce any pho o-ca aly ic deg ada ion unde simila condi ions ( esul no shown). By
con as , he illumina ion o he samples wi h ei he UV o isible ligh ende ed a clea change in
hei WCA. Figu e 4 shows he ime e olu ion o he WCA o hese samples ha we e i s i adia ed

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wi h isible ligh (zone 1), hen wi h UV ligh (zone 2) and inally le in he da k (zone 3). The h ee
samples p esen ini ially a WCA highe han 90º, hus depic ing a hyd ophobic beha io . Fu he mo e,
we link he high ini ial WCA o sample C (130⁰) o he high oughness o he ilm (4.7 nm) in
ag eemen wi h he p emises o he Wenzel model o su ace we ing [44]. Mos ema kable in
Figu e 4 is ha samples B and C expe ienced a con inuous dec ease in WCA when hey we e
i adia ed wi h isible ligh , a ea u e ha mus be linked wi h he inco po a ion o ni ogen wi hin a
s oichiome ic TiO2 la ice a he ou mos su ace laye s o ma e ial. I is wo h no ing ha a e
con ac ing he su ace o samples A, B o C wi h wa e , he XPS spec a aken a e d ying did no
show any signi ican di e ence wi h espec o he o iginal samples, excep o a b oadening in he
shape o he O1s spec a in he high BE side ha we a ibu e o some addi ional hyd oxyla ion o he
su ace.
In line wi h p e ious esul s [11, 23, 33, 46], he desc ibed expe imen s con i m ha WCA ligh
induced-changes and pho o-ca aly ic ac i i y a e no necessa ily equi alen o es ing he pho o-
ac i i y o TiO2. Acco ding o he schemes in Figu e 1, he ou mos su ace laye s o all samples (i.e.
wi hin he pene a ion ange o he XPS echnique) p esen a TiO2 s oichiome y, wi h samples B and
C con aining a ce ain concen a ion o N-O-like species. The WCAs o he h ee samples espond o
he illumina ion o ligh , UV (sample A) and UV and isible (samples B and C). Ye , only sample A,
wi h a TiO2 s ochiome y h oughou he whole sample hickness, p esen s pho o-ca aly ic ac i i y
owa ds he deg ada ion o dye molecules. Acco ding o p e ious in es iga ions in ou labo a o y,
hese esul s con i m ha he e is a TiO2 pho o-ac i a ed su ace mechanism esponsible o changing
he su ace we abili y beha io , e en when he ilm do no show any no iceable esponse when
pe o ming dye decolo a ion es s [23]. In his ega d, he absence o pho o-ca aly ic ac i i y in
samples B and C mus be ela ed wi h he ac ha hei inne laye s a e sub-s oichiome ic and,
he e o e, p esen a high concen a ion o oxygen acancies. Unde hese condi ions, i seems ha he
elec on-hole pho o-exci a ion p ocesses a e no e icien and ha mos ca ie s mus ecombine a he
la ice de ec s, so hey do no each he su ace. We en a i ely called Scho ky Ba ie D i en Pho o-
ac i i y he ype o pho o-ca aly ic ac i i y ha equi es he mig a ion o pho o-gene a ed elec on-
hole pai s om he in e io o he ma e ial up o he su ace as. The e o e, ou esul s he e con i m
ha pho o-induced WCA a ia ions only in ol e mechanisms a he e y i s ou mos monolaye s o
he ma e ial [33], a esponse ha we en a i ely call shallow pho o-ac i i y.
Ou esul s also e eal ha a shallow pho o-ac i e esponse a ec ing he WCA can be induced by
illumina ing N-doped TiO2 wi h isible ligh , wi h WCA s eady-s a e alues a ound 50° and 20° o
samples B and C, espec i ely, whe eas supe hyd o ilici y is a ained wi h UV ligh . The eco e y in
he da k o he WCA o he h ee samples con i ms he ull e e sibili y o his ans o ma ion.
Recen ly, he isible pho o-ac i i y o N-doped TiO2 has been ela ed wi h he p esence o he N1s
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species a a ound 400 eV o binding ene gy (in ou case he N1s peaks a a ound 398.8 and 401.2 eV),
a ibu ed o N-O like species [33,45-47]. Ou WCA pho o-ac i i y esul s con i m his p e ious
a ibu ion and sus ain ha hese species can be in ol ed in he isible ligh su ace ac i a ion o TiO2.
Fu he mo e, since samples B and C p esen simila concen a ion o ni ogen, he di e en inal s a e
o WCA a e isible ligh i adia ion mus be a ibu ed o hei di e en oughness: acco ding o he
Wenzel model, he WCA o ei he hyd ophobic o hyd ophilic samples expe ience an addi ional
inc ease (hyd ophobici y) o dec ease (hyd ophilici y) wi h espec o he WCA o a la su ace o
equi alen composi ion. The e o e, he endency in he WCA o he o iginal samples be o e
i adia ion (i.e., WCA (Sample A) < WCA (Sample B) < WCA (Sample C)) and o samples B and C
a e isible i adia ion (WCA (Sample B)>WCA (Sample C) mus be linked wi h he p og essi e
inc ease in su ace oughness om sample A o C.
In summa y, he expe imen s abo e con i m ha N-doped TiO2 p esen s su ace pho o-ac i i y when
illumina ed wi h isible ligh e en i i is pho o-ca aly ically ine unde bo h isible o UV ligh
illumina ion. Mo eo e , ou esul s ha e also shown ha he changes in he WCA can be uned by
modi ying he su ace oughness. The implica ions o hese wo ea u es o mic o luidic applica ions
o o he ab ica ion o sel -cleaning su aces in in e io s (i.e., in he absence o UV ligh ) a e ob ious
and should pe mi he ab ica ion o sma esponsi e su aces wi h a con ollable su ace we ing.
O e all, we demons a e ha shallow and Scho ky ba ie d i en pho o-ac i i ies a e no equi alen
and ha , consequen ly, hey mus be s udied sepa a ely.
ACKNOWLEDGMENT:
(P ojec s P09-CTS- 5189, TEP5283 and FQM-6900) and he
Minis y o Science and Inno a ion (P ojec s CONSOLIDER CSD2008-00023, MAT2010-21228,
MAT2010-18447) o inancial suppo . We also acknowledge he Ins i u e o Ion Beam Physics and
Ma e ials Resea ch a he Fo schungszen um D esden-Rossendo .
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REFERENCES:
1 Hu um, D.C.; Ag ios, A. G.; G ay, K. A., J. Phys. Chem. B 2003, 107, 4545-4549.
2 Huang, W.X.; Deng, W.; Lei, M.; Huang, H., Appli. Su . Sci. 2011, 257, 4774-4780.
3 Wang, R.; Hashimo o, K.; Fujishima, A.; Chikuni, M.; Kojima, E.; Ki amu a, A.;
Shimohigoshi, M.; Wa anabe, T., Na u e 1997, 388, 431-432.
4 Be ancu R.,Ma ınez-O e o A., Elias X., Rome o-Gomez P., Colod e o S., Miguez
H.,Ma o ell J., Sol. Ene gy Ma e . Sol. Cells 2012, 104, 87–91.
5 Chen, X.; Mao, S.S., Chem. Re . 2007, 107, 2891-2959.
6 Asahi, R.; Mo ikawa, T.; Ohwaki, T.; Aoki, K.; Taga Y., Science 2001, 293, 269-271.
7 Sak hi el, S.; Jancza ek, M.; Ki sch, H. J., Phys. Chem. B 2004, 108, 19384.
8 Diwald, O.; Thompson, T. L.; Zubko , T.; Go alski, E. G.; Walck, S. D.; Ya es, J. T., J. Phys.
Chem. B 2004, 108, 6004.
9 Nosaka, Y.; Ma sushi a, M.; Nasino, J.; Nosaka, A. Y., Sci. Technol. AdV. Ma e . 2005, 6,
143-148.
10 G acia F.; HolgadoJ. P.;Caballe oA.;Gonzalez-ElipeA. R., J. Phys. Chem. B, 2004, 108,
17466–17476.
11 Rome o-Gomez P.; Hamad S.;Gonzalez J. C.;Ba anco A.; J. P.;Co ino J.; Gonzalez-
Elipe A. R., J. Phys. Chem. C, 2010, 114, 22546–22557
12 Di Valen in, C.; Pacchioni, G.; Selloni, A.; Li aghi, S.; Giamello, E., J. Phys. Chem. B 2005,
109, 11414-11419.
13 Diwald, O.; Thompson, T. L.; Go alski, E. G.; Walck, S. D.; Ya es, J. T., J. Phys. Chem. B
2004, 108, 52-57.
14 Ya es, H. M.; Nolan, M. G.; Sheel, D. W.; Pemble, M. E., J. Pho ochem. Pho obiol. A: Chem.
2006, 179, 2013-223.
15 Li aghi, S.; Paganini, M. C.; Giamello, E.; Selloni, A.; Di Valen in, C.; Pacchioni, G., J. Am.
Chem. Soc. 2006, 128, 15666-15671.
16 Lu, JW.; Su, Fl.; Huang, Zq.; Zhang, CX. ; Liu, Y.; Ma, XB.; Gong, JL., RSC Ad . 2013, 3, 3,
720-724.
17 Ba olo, G. ; Li aghi, S.; Chiesa, M.; Paganini, MC.; Giamello, E., J. Phys. Chem. C. 2012,
116, 20887-20894.
1
2
3
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
53
54
55
56
57
58
59
60
61
62
63
64
65
9
18 Pelaez, M.; Nolan, NT.; Pillai, SC.; See y, MK.; Fala as, P.; Kon os, AG.; Dunlop, PSM.;
Hamil on, JWJ.; By ne, JA.; O'Shea, K.; En eza i, MH.; Dionysiou, DD., Appl. Ca . B-En .
2012, 125, 331-349.
19 Sel am, K.; Balachand an, S.; Velmu ugan, R.; Swamina han, M., Appl. Ca A Gen. 2012,
413,213-222.
20 Huang, D.; Miyamo o, Y.; Ding, J.; Gu, J.; Zhu, S.; Liu, Q.; Fan, T.; Guo, Q.; Zhang, D., Ma .
Le . 2011, 65, 326-328.
21 Li aghi, S.; Paganini, M. C.; Giamello, E.; Selloni, A.; Di Valen in,C.; Pacchioni, G., J. Am.
Chem. Soc. 2006, 128, 15666-15671
22 Huang, T.; Huang, W.; Zhou, C.; Si u, Y.; Huang, H., su . coa . echnol 2012, 213, 126-132.
23 Rico, V.; Rome o, P.; Hueso, J.L.; Espinos, J.P.; Gonzalez-Elipe, A.R., Ca al. Today, 2009,
143, 347-354.
24 Zubko , T.; S ahl, D.; Thompson, T. L.; Panayo o , D.; Diwald, O.; Ya es, J. T., J. Phys.
Chem. B 2005, 109, 15454-15462.
25 Thompson, T. L.; Ya es, J. T., Chem. Re . 2006, 106, 4428.
26 Nakajima, A.; Koizumi, S.; Wa anabe, T.; Hashimo o, K., Langmui 2000, 16, 7048-7050.
27 Sun, W.; Zhou, S.; Chen P.; Peng, L., Chem. Commun. 2008, 5, 603–605
28 Sahoo, M.; Ma hews, T.; An ony, R.P.; K ishna, D. N.; Dash, S.; Tyagi, A. K., Ma e .
In e aces, 2013, 5, 3967–3974.
29 Bo as, A.; Ba anco, A.; Gonzalez-Elipe, A.R., Langmui , 2008, 24, 8021–8026.
30 Fujishima, A; Zhang, XT., Comp es Rendus Chimie, 2006, 9, 750-760.
31 Rengi o-He e a, Julian A.; Pie zchała K.;Sienkiewicz A.; L.;Kiwi J.; Mose Jacques E.;
Pulga in C., J. Phys. Chem. C, 2010, 114, 2717–2723.
32 Bo as,A.; Gonzalez-Elipe, A.R., Langmui 2010, 26,15875–15882.
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Figu e 3

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Figu e 4