A kinetic and in situ infrared spectroscopic study of the Fe(CN) 63−/Fe(CN) 64− couple on platinum single crystal electrodes

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 456; no. 1; pp. 113 - 120
• Main Authors: Kitamura, Fusao, Nanbu, Noritoshi, Ohsaka, Takeo, Tokuda, Koichi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.1998; Elsevier Science
• Subjects: Chemistry; Electrochemistry; Electrode kinetics; Electrodes: preparations and properties; Exact sciences and technology; General and physical chemistry; Hexacyanoferrate; Other electrodes; Platinum single crystal electrodes; Hexacyanoferrate; Electrode kinetics; Platinum single crystal electrodes; Oxidation reduction; Fourier transformation; Crystal orientation; In situ; Electron transfer; Transition metal; Experimental study; Single crystal; Infrared spectrometry; Medium effect; Platinum; Electrode reaction; Strontium Chlorides; Kinetics; Electrochemical reaction; Potassium Hexacyanoferrates; Disk electrode; Electrical impedance; Potassium Perchlorates
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/S0022-0728(98)00166-1

Rate constants of the redox-electrode reaction for the Fe(CN) 6 3−/Fe(CN) 6 4− couple at platinum (111), (100) and (110) single crystal electrodes in 0.1 M KClO 4 solution were obtained by ac impedance measurements. The rate constants were found to be largely dependent on the surface orientation, and increased along the series of (110)<(100)<(111). The results strongly suggest that the electron transfer process for the couple would not obey a simple outer-sphere mechanism. An in situ IR spectroscopic observation of each electrode surface in the solution containing 1 mM K 4Fe(CN) 6 clearly indicated the presence of adsorbates ascribable to the cyanide group on every surface, and the spectral features on the (111) surface were found to be different from those on (100) and (110). The dependence of the rate constant at the (111) surface on the substrate concentration and the electrolyte cation was also investigated.