Electrochemical Properties of a Porphyrin-Cobalt (II) Adsorbed on Silica–Titania–Phosphate Composite Surface Prepared by the Sol–Gel Method

✍ Scribed by Ana M. Castellani; Yoshitaka Gushikem

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 139 KB
• Volume: 230
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2000.7091

✦ Synopsis

SiO 2 /TiO 2 /phosphate was obtained by the sol-gel processing method, having the following characteristics: specific surface area S BET = 800 m 2 g -1 , Ti = 14.8 wt% and P = 1.5 wt%, and ion exchange capacity of 0.58 mmol g -1 . The tetrakis(1-methyl-4-pyridyl) porphyrin ion, H 2 TmPyP 4+ , was immobilized on the matrix surface by an ion exchange reaction and then metallated in situ with Co(II), resulting in SiO 2 /TiO 2 /phosphate/CoTmPyP material. The amount of CoTmPyP incorporated to the matrix was 35.0 µmol g -1 . Cyclic voltammetry studies and rotating disk electrode experiments using a carbon paste electrode made with the material were carried out. The immobilized complex catalyzed O 2 reduction to H 2 O at -0.22 V in 1 mol L -1 KCl solution at pH 6.8. The cathodic current intensities plotted against O 2 concentrations, between 1 and 11 ppm, showed a linear correlation.