Study of orientation mode of cobalt-porphyrin on the surface of gold electrode by electrocatalytic dioxygen reduction

✍ Scribed by Guofang Zuo; Huiqing Yuan; Jiandong Yang; Ruixue Zuo; Xiaoquan Lu

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 682 KB
• Volume: 269
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/j.molcata.2006.11.041

✦ Synopsis

Three orientation modes of self-assembled monolayers (SAMs) of cobalt-porphyrins on the surface of gold electrode have been prepared and tested in the electroreduction of dioxygen, such as cobalt-5-(4-aminophenyl)-10,15,20-triphenylporphyrin binding covalently to 3-mercaptopropionic acid pre-assembled on gold (Co-ATP-MPA); cobalt-tetra-[p-(3-mercaptopropyloxy)-phenyl]-porphyrin (Co-TMPP) and cobalt-tetraphenyl-porphyrin axially attached with 4-mercaptopyridine SAMs pre-assembled on gold (Co-TPP-4MPY). A cyclic voltammetric investigation was carried out in an attempt to elucidate the net reaction to the dioxygen reduction. These modes were all active in electrocatalytic reduction of dioxygen through a two-electron mechanism with hydrogen peroxide produced. By combining imidazole axial with Co-TPP and the above cobalt-porphyrin SAMs and together with by testing the multilayer cobalt-porphyrin films by reduction dioxygen, the study confirmed that the electrocatalytic properties of metalloporphyrin was directly related with the structure or orientation of porphyrin ring on the surface of the electrodes.