A computational study of the mechanism of hydrogen evolution by cobalt(diimine-dioxime) catalysts. - Laboratoire de Chimie des Processus Biologiques Accéder directement au contenu
Article Dans Une Revue Chemistry - A European Journal Année : 2013

A computational study of the mechanism of hydrogen evolution by cobalt(diimine-dioxime) catalysts.

Résumé

Cobalt(diimine-dioxime) complexes catalyze hydrogen evolution with low overpotentials and remarkable stability. In this study, DFT calculations were used to investigate their catalytic mechanism, to demonstrate that the initial active state was a Co(I) complex and that H2 was evolved in a heterolytic manner through the protonation of a Co(II)-hydride intermediate. In addition, these catalysts were shown to adjust their electrocatalytic potential for hydrogen evolution to the pH value of the solution and such a property was assigned to the presence of a H(+)-exchange site on the oxime bridge. It was possible to establish that protonation of the bridge was directly involved in the H2-evolution mechanism through proton-coupled electron-transfer steps. A consistent mechanistic scheme is proposed that fits the experimentally determined electrocatalytic and electrochemical potentials of cobalt(diimine-dioxime) complexes and reproduces the observed positive shift of the electrocatalytic potential with increasing acidity of the proton source.

Dates et versions

hal-01063045 , version 1 (11-09-2014)

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Citer

Anirban Bhattacharjee, Eugen S Andreiadis, Murielle Chavarot-Kerlidou, Marc Fontecave, Martin J Field, et al.. A computational study of the mechanism of hydrogen evolution by cobalt(diimine-dioxime) catalysts.. Chemistry - A European Journal, 2013, 19 (45), pp.15166-74. ⟨10.1002/chem.201301860⟩. ⟨hal-01063045⟩
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