Nafion modified TiO2 electrodes: photoresponse and sensitization by Ru(II)-bipyridyl complexes

✍ Scribed by Ladislav Kavan; Michael Grätzel

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 775 KB
• Volume: 34
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(89)85029-7

✦ Synopsis

Rutile single crystal and anatase polycrystalline electrodes were modified by a cation-exchanging NAFION polymeric film. The photoelectrochemical properties of TiO,/NAFION/(H+/Li+) system are comparable with that of pure TiO,. A TiO,/NAFION/Ru(bpy)i + system shows relatively weak sensitized photocurrents with a maximum at 450 nm. A RuL, (L = 2,2'-bipyridyl-4,4'-dicarboxylic acid) complex can be incorporated in the NAFION film at pH values when the carboxylic groups are protonated, ie the RuL, complex is positively charged. At higher pH values, when RuL, is charged negatively, a NAFION film blocks the transport of RuL,. This effect was used for protecting the adsorbed layer of RuL, on TiO, against desorption. Electrodes sensitized with adsorbed RuL, and protected with NAFION show stable currents of photoelectrochemical hydroquinone oxidation at pH 67.