Electrochemical reduction of 2,6-diphenylpyrylium cations by spin-polarized electrons. The Hedvall effect

✍ Scribed by A.D. Modestov; V.E. Kazarinov

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 393 KB
• Volume: 206
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)85572-6

✦ Synopsis

The influence of transition from fewmagnetism to paramagnetism on the activity of metal catalysts (the Hedvall effect ) is explained on the basis of induced spin-polarization of adsorbed radicals. This assumption was verified using the electrochemical reduction of 2,6diphenylpyrylium cations as a model. This reduction leads to formation of uncharged radicals that undergo fast dimerization in the bulk of the solution. Cations were reduced by spin-polarized electrons that have been generated in the conduction band of a pGaAs photocathode, illuminated under conditions of optical orientation. When electron spin-polarization was "switched on" an inhibition of the reduction rate was observed.