Table of Contents
Laser Chemistry
Volume 3, Issue 1-6, Pages 293-305

Redox Properties of Cobalt Tetraphenyl Porphyrin Adsorbed on Semi-Conductor Oxides Studied by Photoacoustic Spectroscopy

1ERA 167 Photophysique et Photochimie moléculaire Université de Bordeaux 1, Talence Cedex F33405, France
2ENSCPB, Université de Bordeaux I, France
3ICSN, Gif-sur-Yvette F91190, France

Copyright © 1983 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Photoacoustic spectroscopy has allowed to show that physisorbed CoIITPP is ground state monooxidized into (CoIIITPP)+ when adsorbed on Nb2O5, TiO2, SrTiO3, ZnO, SnO2. A double oxidation is observed when the porphyrin is adsorbed on WO3. On the contrary when it is adsorbed on ZrO2 and SiO2, oxidation only occurs if the porphyrin has been driven by irradiation in its excited state. It remains in the reduced form when adsorbed on Ta2O5. This behavior has been correlated with the band positions of these various oxides and has allowed to roughly position the oxidation potential of CoTPP in adsorbed state ∼0.8 V higher than in solution (0.5 V/SCE or 5.3 V/vacuum) that is 4.5 V/vacuum.