Korean Chem. Eng. Res., Vol. 45, No. 2, April, 2007, pp. 124-132 { Sn-modified Platinized Ti n oo l Tim Š k Ç Çmm oq l 305-600 re o v 150 (2006 9o 19p r, 2006 12o 22p }ˆ) Characteristics of Ti Platinization for Fabrication Sn-modified Platinized Ti Electrode Kwang-Wook Kim, Seong-Min Kim and Eil-Hee Lee Korea Atomic Energy Research Institute, 150, Deokjin-dong, Yuseong-gu, Daejeon 305-600, Korea (Received 19 September 2006; accepted 22 December 2006) k h l Ti ql Pt l l kr platinized Ti r p rs p re lp, Snp platinized Ti r p v m pml r r p l l. l Ti q l r Pt l r r p p l qs nk mmop r rp, nk r r p er rp pl. rq platinized Ti r p p r r r rp krrp q p p Sn-modified platinized Ti r l p Sn špp r pl n tn m. r r rp r l p p ll v r p kr s e. l p n v m pmp op rp Sn-modified platinized Ti r p k 30 e p rs n q sk. Abstract This work investigated a fabrication way of stable platinized Ti electrode and evaluated the electrochemical characteristics of the Sn-modified platinized Ti electrode in nitrate solution. A Pt electro-plating way to form some open special clearances within the Pt coating layer on etched Ti substrate was very important to remove effectively the residual contaminate due to plating solution out of the fabricated electrode surface and to maximize the actual electrode surface area contacting solution. Both boiling and electro-cleaning processes of the fabricated electrode was essential to obtain a stable platinized-pt electrode with reproducible and stable surface property which was necessary for the correct evaluation of Sn coverage on the electrode. The electro-cleaning caused a morphology change of the platinized Ti electrode surface with some downy hair-like polyps formed during the deposition disappearing, which made the electrode stable. The Sn-modified platinized Ti electrode in this work showed the best electro-activity for nitrate reduction, when it was fabricated through the Pt electro-plating of about 30 minutes. Key words: Nitrate Reduction, Sn-Adatom, Platinized Ti, Pt Electro-Deposition, Platinization 1. v m pmp o p } o r rp p l p n pp, r p p p r ol l r r kr p p r kl n tn r p n p [1]. v mpmp o o p rp p n Pt, Ni, Ti p r p rpv l, Pt l Sn, Cu, Ge pq submonolayer ˆ e (p adatom) Pt r p p p l l v p [2-5], t To whom correspondence should be addressed. E-mail: nkwkim@kaeri.re.kr l Sn eˆ Pt r p n rp p [6]. Snp Pt r p o q v mpl Ž ~l Snp e l pp, Ptp p l l Pt ~ r p lr n l. p r o rr ql Pt k Ž l Pt r ~ rs rp. Pt o q r r, r, e, kr p Tip rr. Ti p tl d l p ˆ pl rp Ptp Ž l n p k r p p, Ti l Ptp p p p k r qn k Van der Waals šl p r qnl p p k r p [7-9]. 124
Snp Pt r p Sn šp(coverage)p o r n (charge capacity)p rp n. p r n p Pt r p -ˆ ro mll cyclic voltammogram( rk-r )p llv. p Ž Ti r ~ (platinized Ti)p l l p }l nk p qs, p r mmop qn l -ˆ ro mll r n p rp. p r o l Pt r r(electrolytic cleaning)p n v, p rl -ˆ ro mll p cyclic voltammogram ˆ v rp l r p r l np ppp l l l. r Sn-modified platinized Ti r p o kr platinized Ti r rsm rq r p } p n. Ptl Ptp (platinized Pt)l p l l pp [10], Til Ptp (platinized Ti)l l rp p l pv kp ˆp, p p t n Pt r rs p [9, 11-12]. Iniesta ˆmp o r p rp p Ž Ti r p l mp, platinized Ti r p ~m p p p o r ~ e k l p r r r rp tn p mp, r r r l ˆ r v kk [11]. Hu p Ti r p r r rl rk-r p Pt p Pt oqp place-exchange processl p s(morphology)p l p p l mp l -ˆ ro mll cyclic voltammogramp r v mp, r l ˆ l v p l v p v kk [12]. l Snp Sn-modified platinized Ti r rs o Til Pt v mpm nkl p rq r p r r l l r platinized Ti r rs Sn-modified platinized Ti r p r p l l. 2. Pt Žp o Ti q v 1.5 mm p 1 cmp Ti mpl n m. Ti p p vp r m l pr t o l Ti q Pt rl 90 o Cl 20 wt% oxalic acid (m ) } l } mp, l Ti q l qs oxalate r o l pž } 10, p 10 rp v }p l ~r } l. l Ti l Pt p 1.0 M HCll 0.075M H 2 p n Pt pm nkl tr p silver silver-chloride electrode (SSE) n -0.05 V SSE rrkl l. nkp m m r p r l p pp nkp m 80 o C p l nkp v v l nkp Pt pm ƒv, p nk l l np o eˆ, l l nk m 70 o C r l n m. nkp n Pt pm m r l ˆ sr q n m. Ptp m r pp k o l Pt r Platinized Ti r p rs 125 p m p r p r lp, rq r morphologyp SEM(scanning electron microscopy : JSM- 5200) p v r l. rq Platinized Ti r p v l pr e l l qs m pmp r p -0.21~1.3 V SSE ro l 300 mv/sec t pr r rp mp, p 50 p cyclic voltammogramp Pt o -ˆ ro m r~ ro l 50 mv/sec t cyclic voltammogramp r m. rq platinized Ti r l Snp eˆ o 0.1 M HClO 4 nkl 0.5 mm SnCl 2 p n nkl 10 lp [2, 3, 6, 13], p r p Sn šp(coverage)p o l p -ˆ ro l cyclic voltammogramp r m. v m pm(no 3 )l rq Sn-modified platinized Ti r p p o l 0.05 M NaNO 3 p v 0.1 M HClO 4 nkl linear sweep voltammogramp r l. v m pm nkp vv r kp HClO 4 nkp n po ClO 4 pmp Cl, SO 4 2,PO 4 3 pml l Pt p l NO 3 p qp q rl r NO 3 p r pp p p [14, 15]. l p e p ml lp, n e kp ekp r} lp n m, nkp r }p o p 2 v m pm v(mill-q plus) } r p 18.2 MΩcmp n m. 3. y 3-1. Platinized Ti n oo Pt ~l Pt l l r q k r p p, Til Pt l l rp q k r pv kp ˆp. Snp platinized Ti r l v m pmp r p p k krrp platinized Ti r ~ rs l l r m. Tip d p l ps p p l n p k r pl Tip } tn. e p Pt Tip ˆ Pt p kr l m p p p l. Tip l p Ti p p v p r k l l p s (roughness) pp Pt p p vveˆ rrp m p t, rq r p rp l p. Tip l p m (20 wt%(cooh) 2, 90 o C) l m (30% HCl, 60 o C) l p k r p [16]. p e kl m l p l m l p l p Tip p l p, m l p Ti l vp p TiH 2 p eˆ. TiH 2 p e (1)l p l l n Pt ro(-0.05 V SSE ) p rol d l pm p p l Pt e Pt p kr p l p e p p l l l mv m l p Ti l p n m. Ti+ 2H + + 2e = TiH 2 () s E = 0.66V SSE (1) Korean Chem. Eng. Res., Vol. 45, No. 2, April, 2007
126 në Ëpp Pt Ž e Ž p kr p o l r p v k rkl p tn, l m v p n tn p e p l m. o r kp nkp s l p rr rr k l p Pt p m. r Pt rkp Pt nk l Tip o p voltammogram rp r l. Pt p e (2)m e (3)} Pt(+4) Pt(+2) Pt(0)p ~ pl p k r p [9-11]. 2- + 2e - 2- = PtCl 4 + 2Cl - E = 0.503V SSE 2- PtCl 4 + 2e - = Pt S + 4Cl - E = 0.648V SSE Fig. 1l Pt nkl l Tim Ptl linear sweep voltammogramp ˆ p. Ptl Pt np Fig. 1(A) l +0.1 V SSE l ~ -0.15 V SSE l w ˆ p r (limiting current) e (2)m e (3)p o l p p. ~ w t m w t p voltammogramp p p p p. Til Pt np Fig. 1(B)l k -0.05 V SSE l (2) (3) ~ p w -0.15 V SSE l ˆ e (2) p pl o Pt ql p rkp n p p. wm w t voltammograml Ptl Pt p e (2) p ~ w +0.1 V SSE l ˆ voltammogram rp l r v k r p lt. p p }p Til e (2)p rkp p -0.05 V SSE p v Pt(+2) Ti l Pt p v l e (2)l rkp r tl Ptl } p p. Til p o rkp +0.2~0.0 Vp ro Pt q l d Pt r p, Til Pt Ž p q v k. e (2)p rp pl -0.05 V SSE (+0.15 V SHE ) p ˆ lk Til Ptp p o eq r r r v p pl. Tip n voltammograml r p p 70 o C m v n kp l p r l nk o p. l l Til Ptp p Pt p p l v k rop -0.05 V SSE n l p m. Pt rl n Pt p d lv p pl. p p Pt rl Pt p v n Pt l p p Pt p p l p. Fig. 2l -0.05 V SSE l l Til Pt nm Ptm pll Pt n e l r ˆ p. Ptm Til n mr e -r ˆ p. Ptl n rr (charging current)l p r p r kr l nk v k p pr e -r p. Tip n e -r p p eq o r v k 5 r l pr r p p e or v pr v p pl. p p Tip r e (2)m (3)p Pt pmp 2 o rl p p. e, p Ti l Pt v l Pt(+4) Pt(+2)m Pt(0) o rkp kvp f o r v. p v p r l Pt o v Fig. 1. Linear voltammograms of etched Ti and Pt in 0.07 M H 2 solution. o45 o2 2007 4k Fig. 2. Chronoamperogram of platinization of etched Ti at 0.05 V SSE at 70 o C.
Platinized Ti r p rs 127 Fig. 3. Relation between Pt coating weight and total electricity for platinizing etched-ti. p Pt(+2) l r l Pt(+2) p lv nk p rp v l r l Pt(+2) v v pr l Pt o r pr ˆ. p Ti p n Pt v l o r e v Ti p p Pt pl r pr. Fig. 3l -0.05 V SSE l Til Ptp n r l Ptp p ˆ p. Pt r e l p rp p p. Pt p 4rq pp l Fig. 3p llv n r pp k 62.3%pl. p r p p l ˆ p p [8, 17]. v kpl r pp 100% v p Pt(+4) Pt(0) l o v k Pt(+2) ~ Pt(0) o r p p p Pt(+4)p Pt(+2) v eˆ n l p. Fig. 4l m l l Tim p q l -0.05 V SSE l e p 15, 30, 60 p platinized Ti r p SEM vp ˆ p. Til Pt rp l p p p Ti l p pl p k s p tep v 7-8 µm r p p kp (cauliflower) l ˆ Pt q l p p. e p v l r Ti p p Pt l or srp r~ p l e ˆ v p p. l p p n ˆp l pp p p e p lv p n kv p p. Tip tl d p l p v p l e Fig. 4 p Tip Pt p l Ti l q Pt l p r l p p. 3-2. Platinized Ti n Š p rq platinized Ti r p rp Pt r p p lk Pt r p n p. v, m r Fig. 4. SEM photographs of oxalic acid-etched Ti substrate and platinized Ti electrodes with plating times of 15, 30, and 60 minutes at -0.05 V SSE in 0.075 M H 2 solution. o l Pt r p m oqp -ˆ lk. p p Pt r p ˆl. p ˆ ov lk Pt l Sn p pq eˆ pp k Pt l Sn pqp špp r p. Pt p o nkp hexachloroplatinic acid (H 2 ) n Pt r p m pmp l p mmp. m pmp r l n l l p } p r v k [11, 14]. p mm p r rl p r p. p rp r p m ro l r rp p f r p kr q p rk-r p lp p. rq platinized Ti r p l p } r rl p d kr v kk Sn eˆ Sn šp o cyclic voltammogram rp v m nkl r p o linear sweep voltammogram r e r p p v rp l p r p r ll. p opp } p platinized Ti r p n pl tn. rq platinized Ti r p r rp l r -rk p v rp p pl. v, r rp v l m p p -ˆ r cyclic voltammogram q~ r~rp r t l p l. Fig. 5l 15, 30, 60 k Pt r p -0.22~1.3 V SSE ro l 300 mv/sec t 50 r rp 0.5 M nkl r cyclic voltammogramp ˆ p. Korean Chem. Eng. Res., Vol. 45, No. 2, April, 2007
128 në Ëpp Fig. 5. Changes of cyclic voltammograms of platinized titanium electrodes with different plating times with electro-cleaning cycles. l voltammogram rp 3 rp l 3 w llv p. Voltammogram rl }p 1-2 r r r l p o (cathodic polarization)p l r p p }or e lv 1-2 cyclic voltammogramp r r p kr [18]. r cyclic voltammogram p e l m p pp p. 15 p n p m } 50 r p r rl p q m p -ˆ p, p p r p rpp p. r rp v l v rp -ˆ m -ˆ p pp ov o45 o2 2007 4k tl 500 r p r rp p p lp kr p p. r~rp e p lv r l m m ˆ r rk p p. p -ˆ m o ˆ p, r pt (electric double layer) ro m lp t l p non-faradic r r ƒvp pp, p m o pl p p. 30 Žp n r rp l m p -ˆ r p p pp 15 Žl m p p r rp l m p -ˆ v kp r~rp cyclic voltammogram v rp p p. 60 Žp n 15 n r rp j p l Ptp m p -ˆ p v ˆ l pv k. rq platinized Til p r -rk p p p p opl p l p p. Fig. 4(B)-(D)l p e p v q Ž p k nkl m m pmp r l q p m p -ˆ p m p o p p. Fig. 4(E)m (F)l p e p v Pt l p p p p p p krrp oq Pt l ˆ rp t r (transient state step). Pt e, r l d l s p ˆm s v Pt hydrous oxidep, p oxide vp Fig. 5(B)m (C)l o ro l ˆ ˆp o l p k r p. Fig. 5l p r rp v l r~rp rk-r t l p r} rl Pt l v rk l p place-exchange process qnl p r p morphology l p p [12, 19, 20]. v, r p p n ~ v Pt p rp tl p p. Fig. 6l 60 Pt p eˆ r p r r r l SEM vp ˆ p. r r rl s p v Pt p r rp 800 p v p p. p p rl l t kr p(meta-stable) Pt-adatom p r r rl place-exchange process qnl p krrp ˆp s q l l p [12, 21]. r r r nk r evrp r rp tl p. e p 30 60 p n p -ˆ p m p Pt l k p m pml p p p p o l r Pt mpl 0.5 M nkl r r e p -ˆ q, p v 0.5 M nk 100 ppmp m pmp v 0.5 M nk cyclic voltammogram r m, Fig. 7l ˆ p. k 1.2 Vl m p - op p p p, Fig. 5(B)m (C)l m p -ˆ v Pt m Pt o m r tl p p. p Fig. 4l p
Platinized Ti r p rs 129 Fig. 6. SEM photographs of Ti electrode platinized for 60 minutes before and after electro-cleaning. Fig. 7. Cyclic voltammograms of Pt electrode in 0.5 M H 2 SO 4 solutions with and without chloride ions. l Tip y l Pt l p q Ti p p n, p Pt l pm Ti qp r p p sq l l m pmp nkp platinized Ti r p r p e mmop qn p p. p l m pm nkp k p p p p o 30 60 r p r p Fig. 8l ˆ Fig. 8. SEM photographs of cross-sections of Ti electrodes platinized for 30 and 60 minutes. p. ˆ l qp p sq p p. 15 } ˆ r Pt l p l v k rp sq nl r rs l p l p d r l qs nkp r pp Fig. 5(A)l p wp r rl p d Pt r p p. p 30 nm mr p 60 n }p r rl p l sq mmop d r l ovp k p. pr l l p l p Pt Ti r p l r p Pt l m pmp r k Pt p q p (stress)p r l t [11]. r s r p m pmp r p p o l r s platinized Ti r p v r p n l p nk tp m pm r m Fig. 9 l ˆ p. 15 n 1e p p p lp 30 60 n p e p v l m pm v l, 30 Žp n k 4e r l k 13 ppm r l pr 60 Žp n 6e r l k 24 ppm r l p pr. p Pt e p v srp Pt Ž l qs m pmp p sq p p p. Pt r p pr e l p r p s SEMp Korean Chem. Eng. Res., Vol. 45, No. 2, April, 2007
130 në Ëpp Fig. 9. Concentration changes of chloride ions in the solutions during boiling the platinized Ti electrodes in water. ll. Fig. 9p Pt r p p p r mm vp rp r ppp k p. Fig. 10 l Pt r p 10e p l l m pmp r r rp l pv kp np cyclic voltammogram ˆ p. p e p o l p r pv kp r p rp l n mp er r rl p pl r vrr p -ˆ p p n. 15 n Pt p r rs l p rl d m pmp r s r l p r p qlp l p -ˆ m p lp, e p lv p r} l n r p p r} l t nl l p e kp r rl l p -ˆ ˆ p p. Fig. 10l p ˆ Pt r (polycrystalline Pt electrode)p cyclic voltammogram, e p lv ˆ p k ro p p p l vp p (s -ˆ p p p o Fig. 11 s). p p Ptm r p Ti pp rl p rk (ohmic drop) k, Pt r j p rp v platinized Ti r l p Pt-H -ˆ l p k r r nkp ph l p rop p [11]. p l Til Pt e p lv rq r p l l r l sq m r rp tn, Pt p r p mr n rq r p p r r rp Pt p r p l p k p. p p platinized Ti r p r p v Pt r p v r p o l Til n Pt Ž p p m p p. 3-3. Sn y platinized Ti n m s i mj k v m pmp r op o Sn-modified platinized Ti r o45 o2 2007 4k Fig. 10. Changes of cyclic voltammograms of platinized Ti and Pt electrodes with different pretreatments. Fig. 11. Cyclic voltammograms of Pt wire and 15 minute platinized- Pt electrodes before and after Sn-adsorption on the electrodes.
p rs platinized Ti r p l p r pr e k r rp Sn nkl 10 rq m. rq r p l p } r rp lp n l. Fig. 11l 15 platinized Tir Pt mpl r p -ˆ ro mll p Sn r p cyclic voltammogramp ˆ p. Sn špp cyclic volatmmogram p rp r n (charge capacity)p v, ˆ p p l l [2-5, 11, 15]. Pt mplp n p 46% Snp lp, 10 Platinized Pt k 17% r l ppp pl. 30 60 platinized Pt Snp 9%, 2% j l pl. r rp platinized Ti r p n n rl krr voltammogramp lp pl. rq platinized Ti r p l } r rp r} v k n, -ˆ p m l p Sn špp rp e ll. Fig. 12 l Ti, 15 platinized Ti, Sn-modified platinized Ti, Pt, Sn-modified Pt r p v m nk rnk(background) l r voltammogramp ˆ p. v m pm nkp Pt l Snp sq o r n v p p, p p Snp Pt r l qn p p p. Platinized Ti r p Pt r j or p p p platinized Ti r p Pt r r rp p. v mp l rnkl l Snp sq o rol p m p tv k p pp, v m nkl Snp Pt r l sq p rkp v p p. pl po Snp Pt l s Ptm Snp r qnl p l v m pm p Pt r Snp Pt r l l p p p r l pmp p p Snp Pt r l l rkp d p p [15]. Fig. 12l v m n kl p Ti r p ˆ p. Ti r l Platinized Ti r p rs 131 l rkp Pt r l l n k k 1.2 V SSE l p pl, r l Sn sq o l rk l p m p tv kpp p. Ti q~ v m pml l r p ppp pp, platinized Ti r l l k 0.5 V p p p p rol v m pm l r p ˆ pp p. p Snp Ptmp qnl r vp ˆ, Sn p Ti l r p pv k p p p. p p Pt ~ r, rrp r, p rp v platinized Ti r l Snp e v m pmp ol p p Pt r l Snp e n r pp k p. Fig. 13(A)l 15, 30, 60 k platinized Ti r l l Sn p Sn-modified platinized Ti r p v m pm nk rnkl p voltammogramp ˆ p. Sn p l platinized Ti r p v m nkl l p r p sq p p, p p 60 p p r l p ƒvp pp, Fig. 5m Fig. 10l p e p lvl Pt l qs m p Fig. 12. Linear voltammograms of Pt, platinized Ti and etched Ti electrodes with and without modification by Sn in 0.1 M HClO 4 solution with and without 0.05 M NaNO 3. Fig. 13. Linear voltammograms of platinized Ti electrode (A) and Snmodified platinized Ti electrode (B) in 0.1 M HClO 4 solution with and without 0.05 M NaNO 3. Korean Chem. Eng. Res., Vol. 45, No. 2, April, 2007
132 në Ëpp m p l p r r p ƒvp p. Fig. 13(B)l p e p Sn-modified platinized Ti r p v m nkl o r i 60 min (~32 ma/cm 2 ) i 30 min (~30 ma/cm 2 ) i 15 min (~27 ma/cm 2 )p e p r p v m pmp o r ˆ, rnkl p r o r i 30 min (~27 ma/cm 2 ) i 15 min (~26 ma/cm 2 ) i 60 min (~22 ma/cm 2 ) m 30 r p q p r p p. 30 r l q p o r p p p r p er r pl p p. Fig. 4l p Pt p Ti r p mr p n nkl Pt r p 2 or rp p, 15 p 30 p n} Pt pl p sq n r p 3 or p r rp v. 15 n p v kk 30 n r~rp nkl r rp qp p. platinized Ti r rs e, r rp, Pt k r }p np p r e p sq p k p, l p n e p 30 r r p k p. 4. l Til Pt p l l p s Ti p tep p p Pt q rp p lr. Pt l r p sq p p rq Pt r l sq qs nkp r np lp, nk r r p rp n tn m. Snp platinized Ti r p Sn šp rs platinized Ti r p pr e p r rp rp kr eˆ m. rs r p r r rp r l p ll v s k eˆ r p kr e. v m p mp op rp Sn-modified platinized Ti r p k 30 e p rs n q n m. y 1. Greenwood, N.G N. and Earnshaw, A., Chemistry of the Elements, Perggamon Press, Oxford(1984). 2. Lamy-Pitara, E. and Barbier, J., Platinum Modified by Electrochemical Deposition of Adatoms, Applied Catalysis A: General, 149, 49-87(1997). 3. Kerkeni, S., Lamy-Pitara and E., Barbier, J., Copper-Platinum Catalysts Prepared and Characterized by Electrochemical Methods for the Reduction of Nitrate and Nitrite, Chemical Today, 75, 35-42(2002). 4. Gootzen, J.GF.GE., Peeters, P.GG.GJ.GM., Dukers, J.GM.GB., Lefferts, L., Visscher, W. and van Veen, J.G A.G R., The Electrocatalytic Reduction of Nitrate on Pt, Pd, and Pt+Pd Electrode Activated with Ge, J. Electroanal. Chem., 434, 171-183(1997). 5. de Vooys, A.GC.GA., van Santen, R.GA. and van Veen, J.GA.GR., Electrocatalytic Reduction of Nitrate on Palladium/Copper Electrodes, J Molecular Catalysis A; Chemical, 154, 203-215 (2002). 6. Shimazu, K., Goto, R. and Tada K., Electrochemical Reduction of Nitrate ions on Tin-modified Platinum and Palladium Electrodes, Chemistry letters, 2, 204-205(2002). 7. Hayfield, P. C. S., Platinized Titanium Electrode for Cathodic Protection, Platinum Metals Reviews, 27(1), 2-8(1983). 8. Evans, S. A. G., Terry, J. G., Plank, N. O. V., Walton, A. J., Keane, L. M., Campbell, C. J., Ghazal, P., Beattie, J. S., Su, T.-J., Crain, J. and Mount, A. R., Electrodeposition of Platinum Metal on TiN Thin Films, Electrochem. Commun., 7, 125-129(2005). 9. Pazer, J. F. II, Yao, S. A. and Wolfson, S. K. jr., Platinized Titanium Electrodes for Urea Oxidation Pat 1. Demonstration of Efficacy, J. Molecular Catalysis, 70, 217-230(1991). 10. Feltham, A. M. and Spiro, M., Platinized Platinum Electrode, Chemical Reviews, 71(2), 177-193(1971). 11. Iniesta, J., Garcia, J. G., Fernandez, J., Montiel V. and Aldaz, A., On the Voltammetric Behavoir of a Platinzed Titaniuim Surface with Respect to the Specific Hydrogen and Anion Adsorption and Charge Transfer Process, J. Materials Sci., 9, 3141-3145(1999). 12. Hu,G C.-C. and Liu, K.-Y., Voltammetric Investigation of Platinum Oxide. I. Effect of Ageing on Their Formation/reduction Behavior as well as Catalytic Activities for Methanol Oxidation, Electrochimica Acta, 44, 2727-2738(1999). 13. Shimazu, K., Goto, R. and Tada, K., Preparation of Binary Metal Electrocatalysts by Self-assembly of Precursor Ionic Species on Gold a Reduction of Nitrate ions, J. Electroanal. Chem., 529, 20-27(2002). 14. Horanyi, G. and Rizmayer, E. M., Role of Adsorption Phenomena in the Electrocatlytic Reduction if Nitric Acid at a Platinized Platinum Electrode, J. Electroanal.Chem., 140, 347-366(1982). 15. Tada, K. and Shimazu, K., Kinetic Studies of Reduction of Nitrate Ions at Sn-modified Pt Electrodes Using a Quartz Crystal Microbalance, J. Electroanal.Chem., 577, 303-309(2005). 16. Kim, K. W., Lee, E. H., Kim, J. S., Shin, K. H. and Kim, K. H., Effect of an Etching Ti Substrate on a Catalytic Oxide Electrode, J. Electrochem. Soc., 148, B111-B115(2001). 17. Baumgartner, M. E. and Raub, Ch. J., The Electrodeposition of Platinum and Platinum Alloys, Platinum Metals Rev., 32(4), 188-197(1988). 18. Bakos, I. and Horanyi, G., Influence of Deposition Potential on the Voltammetric Behavior of Potentiostatically Formed Platinized Electrodes, J. Electroanal. Chem., 397, 105-100(1995). 19. Burke, L. D., Casey, J. K. and Morrisey, J. A. E., An Investigation of Some of the Variables Involved in the Generation of an Unusual Reactive Site of Platinum, Electrochimica Acta, 38(7), 897-906(1993). 20. Burke, L. D. and Murphy, M. M., Effect of Solution ph on Hydrous Oxide Growth and Reduction of Polycrystalline Platinum, J. Electroanal. Chem., 305, 301-312(1991). 21. Takasu, Y., Fujii, Y., Yasuda, K., Iwanaga, Y. and Matusuda, Y., Electrocatalytic Properties of Ultrafine Platinum Particle for Hydrogen Electrode Reaction in an Aqueous Solution of Sulfuric Acid, Electrochimcia Acta, 34, 453-458(1989). o45 o2 2007 4k