Synergic Effect on Oxygen Reduction Reaction of Strapped Iron Porphyrins Polymerised around Carbon Nanotubes
Résumé
In the context of the development of new bio-inspired catalysts, MN4 complexes exhibit a great potential for small molecules activation in. In particular, metallated porphyrins and phthalocyanines combined with carbon nanotubes have been tested for the oxygen reduction reaction electrocatalytic systems and these nanotube/MN4 hybrids demonstrated promising properties. Here, a series of hybrid materials made of multi-walled carbon nanotubes (MWNTs) coated with strapped porphyrins have been fabricated. Iron porphyrin derivatives have been polymerized around the nanotubes via Hay-coupling and the resulting materials have been fully characterized. Two porphyrins have been probed; both are strapped with the same skeleton and differ only by the prensence or not of overhung carboxylic acids. In the porphyrin, the carboxylic acid group can possibly act as a proton relay between the medium and the catalyst. Whereas the presence of the carboxylic acid groups (acting as intramolecular proton relays) does not exhibit a significant influence on the catalytic properties, the combination of both components-MWNTs and porphyrin-leads to a better catalytic activity than those of the nanotubes or the porphyrins taken separately. The synergic affect is due to MWNTs which ensure the availability of electrons to the porphyrin catalysts and allow the ORR to occur via the 4-electron pathway, avoiding the production of hydrogen peroxide.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
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