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Study of the impedance of a platinum electrode in a redox system.
A2
Journal of Electroanalytical Chemistry
VOL. 1
1. FUNDAMENTAL E L E C T R O C H E M I S T R Y
[1] MECHANISM OF E L E C T R O L Y T I C DEPOSITION AND DISSOLUTION OF METALS. H. F i s c h e r . ( M a x - P l a n c k - I n s t i t u t fiir M e t a l l f o r s c h u n g , Stuttgart, G e r m a n y . ) A n a l . C h e m . , 31 (1959) 33. T h e o r e t i c a l p r i n c i p l e s and r e c e n t d e v e l o p m e n t s in the methodology of r e l a t i v e l y s i m p l e e l e c t r o d e r e a c t i o n s a r e d i s c u s s e d . Some data on c o m p l e x ion d i s c h a r g e and f o r m a t i o n and d i s s o l u t i o n of solid m e t a l s a r e given. KI. Gr. [21 ON THE MECHANISM OF E L E C T R O L Y T I C DEPOSITION AND DISSOLUTItgN'OF SILVER. W. Mehl and J. O ' M . B o c k r i s . (John H a r r i s o n L a b o r a t o r i e s , U n i v e r s i t y ¢)t P en n s y l v an i a, Philadelphia, U. S. A. ) Can. J. Chem. , 37 (1959) 190. Ag e l e c t r o d e s w e r e t r e a t e d a c c o r d i n g to the method of Conway et al. (J. Sci. I n s t r . . 3?, (1956) 400) to produce a p o l y c r y s t a l l i n e s u r f a c e s i m i l a r to " t h e r m a l c tchin,~' . The e x p e r i m e n t s w e r e c a r r i e d out in 1.0 N HC104 with c o n c e n t r a t i o n s of .\gCltJ4 of 0.2 - 0.01 M. S h o r t - t i m e p o l a r i z a t i o n was investigated by the galvanost~ttic method of R o j t a r et al. (Acta P h y s i c o c h i m . U . R . S . S . , 10 (1935) 389, 845) at constant c u r r e n t . S e v e r a l c l e c t r o m i c r o g r a p h s of the etched s u r f a c e s a r e shown. The study indicated that in the m e c h a n i s m of deposition at low o v e r p o t e n t i a i s , the s u r f a c e diffusion of the anions was the p r i n c i p a l r a t e - d e t e r m i n i n g step. At high o v e r p o t e n t i a l s the t r a n s f e r of ions f r o m solution to the e l e c t r o d e was the r at ~ . -d ct er m i n i n g step. The deposition p r o c e s s c o r r e s p o n d e d m o r e c l o s e l y to a model c o n s i s t i n g of s e v e r a l c o n s e c u t i v e s t e p s taking place g e n e r a l l y o v e r the entire s u r f a c e of the e l e c t r o d e r a t h e r than a m o d el w h e r e the ions p a s s e d d i r e c t l y i r o m the solution to local active c e n t e r s on the e l e c t r o d e s u r f a c e . D. S..Ru.
[.~l STUDY OI: TIlE IMPEDANCE OF A PLATINUM E L E C T R O D E IN A REDOX SYSTEM. J . L l o p i s , J . F e r n a n d e z - B i a r g e and M . P S r e z F e r n a n d e z . (Institutode Q u i m i c a Visiea, Madrid, S p a i n . ) E l e c t r o c h i m . Acta, 1 (1959)130. The c f i e c t of adsorption p r o c e s s e s on a Pt e l e c t r o d e in the p r e s e n c e of a r ed o x s y s t t m is m a t h e m a t i c a l l y t r e a t e d , and an e x p r e s s i o n f o r the f a r a d a i c i m p ed an ce is round. ()n this b a s i s , tim s y s t e m s F e 2 ÷ /F e a+(HClaq ) and I2/I-(H2SO4aq) a r e e x p e r i , ~ ntaily studied, by m e a n s of a technique p r e v i o u s l y d e s c r i b e d , tentative e q u i v a It n'. c i r c u i t s a r e dcduced. This is p o s s i b l e only o v e r a l i m i t ed field. N e v e r t h e l e s s , t ,- s s i b l e r e a c t i o n m e c h a n i s m s , which need to be c o n f i r m e d by much m o r e e x t e n . i , , ' work I a r e p r e d i c t e d and G e r i s h e r ' s theory of the i m p o r t a n c e oi a d s o r p t i o n [~Hcnonlcna s e e n l s supported. Visitor's results on active areas are partially confirmed, and the suppositions of' Randlcs on the equivalent circuit are found to be inadequate. Ca. Cas. [4] RED(gXV(gR~ANGE AN GERMANIUM-ELEKTRODEN. F.Beck und 'H. Gerischer. (Max-|4anck-Institut filr Metallforsehung Stuttgart, Germany.) Z. Elektrocnem., 63 (1959) 943. Un t er Verwendung yon G e r r n a n i u r r i - E le k t r od en w e r d e n Redox.reaktionen in den Systemen: C e r s u l f a t in s e h w e f e l s a u r e r LiSsung, K a l i u m h e x a c y a n o f e r r a t ( I I I ) in a l k a l i s c h e r LiSsung, K a l i u m p e r m a n g a n a t in s c h w e f e l s a u r e r LiSsung, Eisen(III)Sulf a t - C h l o r i d e - P e r e h l o r a t in den e n t s p r e c h e n d e n Sliure-LiSsungen, S a u e r s t o f f und W a s s e r s t o f f p e r o x y d in a l k a l i s c h e r Lbsung, K3[Fe(CN)6]/K4[Fe(CN) 6] in s a u r e r LSsung, sowie Vanadium(II)Sulfat in s c h w e f e l s a u r e r Lbsung u n t e r s u c h t . E s wird gefundcn, class a l l e R e d o x - R e a k t i o n e n tiber den V a l e n z b a n d m e c h a n i s m u s ablaufen
Journal of Electroanalytical Chemistry
VOL. 1
1. FUNDAMENTAL E L E C T R O C H E M I S T R Y
[1] MECHANISM OF E L E C T R O L Y T I C DEPOSITION AND DISSOLUTION OF METALS. H. F i s c h e r . ( M a x - P l a n c k - I n s t i t u t fiir M e t a l l f o r s c h u n g , Stuttgart, G e r m a n y . ) A n a l . C h e m . , 31 (1959) 33. T h e o r e t i c a l p r i n c i p l e s and r e c e n t d e v e l o p m e n t s in the methodology of r e l a t i v e l y s i m p l e e l e c t r o d e r e a c t i o n s a r e d i s c u s s e d . Some data on c o m p l e x ion d i s c h a r g e and f o r m a t i o n and d i s s o l u t i o n of solid m e t a l s a r e given. KI. Gr. [21 ON THE MECHANISM OF E L E C T R O L Y T I C DEPOSITION AND DISSOLUTItgN'OF SILVER. W. Mehl and J. O ' M . B o c k r i s . (John H a r r i s o n L a b o r a t o r i e s , U n i v e r s i t y ¢)t P en n s y l v an i a, Philadelphia, U. S. A. ) Can. J. Chem. , 37 (1959) 190. Ag e l e c t r o d e s w e r e t r e a t e d a c c o r d i n g to the method of Conway et al. (J. Sci. I n s t r . . 3?, (1956) 400) to produce a p o l y c r y s t a l l i n e s u r f a c e s i m i l a r to " t h e r m a l c tchin,~' . The e x p e r i m e n t s w e r e c a r r i e d out in 1.0 N HC104 with c o n c e n t r a t i o n s of .\gCltJ4 of 0.2 - 0.01 M. S h o r t - t i m e p o l a r i z a t i o n was investigated by the galvanost~ttic method of R o j t a r et al. (Acta P h y s i c o c h i m . U . R . S . S . , 10 (1935) 389, 845) at constant c u r r e n t . S e v e r a l c l e c t r o m i c r o g r a p h s of the etched s u r f a c e s a r e shown. The study indicated that in the m e c h a n i s m of deposition at low o v e r p o t e n t i a i s , the s u r f a c e diffusion of the anions was the p r i n c i p a l r a t e - d e t e r m i n i n g step. At high o v e r p o t e n t i a l s the t r a n s f e r of ions f r o m solution to the e l e c t r o d e was the r at ~ . -d ct er m i n i n g step. The deposition p r o c e s s c o r r e s p o n d e d m o r e c l o s e l y to a model c o n s i s t i n g of s e v e r a l c o n s e c u t i v e s t e p s taking place g e n e r a l l y o v e r the entire s u r f a c e of the e l e c t r o d e r a t h e r than a m o d el w h e r e the ions p a s s e d d i r e c t l y i r o m the solution to local active c e n t e r s on the e l e c t r o d e s u r f a c e . D. S..Ru.
[.~l STUDY OI: TIlE IMPEDANCE OF A PLATINUM E L E C T R O D E IN A REDOX SYSTEM. J . L l o p i s , J . F e r n a n d e z - B i a r g e and M . P S r e z F e r n a n d e z . (Institutode Q u i m i c a Visiea, Madrid, S p a i n . ) E l e c t r o c h i m . Acta, 1 (1959)130. The c f i e c t of adsorption p r o c e s s e s on a Pt e l e c t r o d e in the p r e s e n c e of a r ed o x s y s t t m is m a t h e m a t i c a l l y t r e a t e d , and an e x p r e s s i o n f o r the f a r a d a i c i m p ed an ce is round. ()n this b a s i s , tim s y s t e m s F e 2 ÷ /F e a+(HClaq ) and I2/I-(H2SO4aq) a r e e x p e r i , ~ ntaily studied, by m e a n s of a technique p r e v i o u s l y d e s c r i b e d , tentative e q u i v a It n'. c i r c u i t s a r e dcduced. This is p o s s i b l e only o v e r a l i m i t ed field. N e v e r t h e l e s s , t ,- s s i b l e r e a c t i o n m e c h a n i s m s , which need to be c o n f i r m e d by much m o r e e x t e n . i , , ' work I a r e p r e d i c t e d and G e r i s h e r ' s theory of the i m p o r t a n c e oi a d s o r p t i o n [~Hcnonlcna s e e n l s supported. Visitor's results on active areas are partially confirmed, and the suppositions of' Randlcs on the equivalent circuit are found to be inadequate. Ca. Cas. [4] RED(gXV(gR~ANGE AN GERMANIUM-ELEKTRODEN. F.Beck und 'H. Gerischer. (Max-|4anck-Institut filr Metallforsehung Stuttgart, Germany.) Z. Elektrocnem., 63 (1959) 943. Un t er Verwendung yon G e r r n a n i u r r i - E le k t r od en w e r d e n Redox.reaktionen in den Systemen: C e r s u l f a t in s e h w e f e l s a u r e r LiSsung, K a l i u m h e x a c y a n o f e r r a t ( I I I ) in a l k a l i s c h e r LiSsung, K a l i u m p e r m a n g a n a t in s c h w e f e l s a u r e r LiSsung, Eisen(III)Sulf a t - C h l o r i d e - P e r e h l o r a t in den e n t s p r e c h e n d e n Sliure-LiSsungen, S a u e r s t o f f und W a s s e r s t o f f p e r o x y d in a l k a l i s c h e r Lbsung, K3[Fe(CN)6]/K4[Fe(CN) 6] in s a u r e r LSsung, sowie Vanadium(II)Sulfat in s c h w e f e l s a u r e r Lbsung u n t e r s u c h t . E s wird gefundcn, class a l l e R e d o x - R e a k t i o n e n tiber den V a l e n z b a n d m e c h a n i s m u s ablaufen