An electrochemical and spectroelectrochemical study of pentacoordinated CoTPP on glassy carbon electrode

详细信息    查看全文

• 作者：Hé ; loï ; se H. De Paz ; Christelle Mé ; dard ; Mario Morin ; ^{morin.mario@uqam.ca}
• 关键词：Oxygen reduction reaction ; Catalyst ; Carbon surface modification ; Porphyrins ; Spectroelectrochemistry
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2010
• 出版时间：1 October 2010
• 年：2010
• 卷：648
• 期：2
• 页码：163-168
• 全文大小：417 K

文摘

A glassy carbon electrode (GCE) modified with a monolayer of 4-aminothiophenol (4-ATP) and 5,10,15,20-meso-tetraphenylporphyrin cobalt (CoTPP) was prepared and used to examine the electroreduction of oxygen. Cyclic voltammetry showed that CoTPP chemisorbed on carbon via a 4-ATP monolayer (GCE/4-ATP¨CCoTPP) displayed a catalytic effect similar to that of physisorbed CoTPP on a GCE (GCE/CoTPP). UV¨Cvisible spectra recorded in solution and on chemisorbed layers showed that pentacoordination of the cobalt and a cobalt oxidation state +II were required to facilitate the complexation with oxygen. A stable oxygenated intermediate (4-ATP¨CCo^(II)TPP¨CO₂) was identified both in solution and on a carbon substrate. Finally, UV¨Cvisible reflectance (UVDRS) spectra recorded at different potentials revealed the relation between this oxygenated intermediate and the production of peroxide. Based on these data a catalytic mechanism is proposed.