Effect of light upon electroreduction of 4,4′-bipyridyl and methyl viologen in aqueous solutions

摘要: The limiting current for the polarographic electroreduction of 4,4′-bipyridyl or methyl viologen to corresponding dihydrobipyridyl increases when electrode is irradiated by light wavelengths between 300 and 400 nm. This photoeffect interpreted qualitatively as a catalytic process in solution surrounding electrode, consisting ejection an electron from photoexcited subsequent radical thus formed back dihydrobipyridyl, net chemical result being reduction water photoejected electron. At negative potentials increase photocurrent occurs; this explained at surface under action atomic hydrogen secondary product photoprocess.