Cathodic carboxylation of gold in thick {Au-CO2}n layers. A model for reversible electrochemical sequestration of CO2 - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Electrochemistry Communications Année : 2015

Cathodic carboxylation of gold in thick {Au-CO2}n layers. A model for reversible electrochemical sequestration of CO2

Résumé

Catalytic redn. of CO2 (satd. in org. polar solvents, e.g. N,N-dimethylfomamide, contg. Me4NX or NaBF4) was achieved at smooth gold electrodes and at glassy carbon electrodes galvanostatically capped with a thin layer of gold. Under these quite explicit conditions, very sharp redn. steps were obsd. near - 1.5 V vs. With small cations listed above, an unexpected behavior was obsd., a progressive electrode inhibition occurring upon several scans or after a fixed-potential electrolysis at E \textless - 1.7 V. This phenomenon could be attributed to the insertion of CO2 into gold, leading to the formation of a thick iono-metallic multi-strata layer (less conducting than pure metal) that grows with the electrode charge. The formation of this new interface is due to the concur of three elements: transient CO2 anion radical, the metal, and rather small-sized cations (M+ = Na+ or TMA+), the three possibly assocd. in a form \Au-CO-2,M+\ apparently very reactive with oxygen, moisture, and with some org. π-acceptors. Upon multi-scans up to - 2.2 V, the thickness of formed layer progressively increases reaching more than 10- 7 to 10- 6 mol cm- 2. Such multi-layers undergo decompn. in the anodic domain at about + 1.7 V liberating CO2 beforehand trapped in Au. Coulometric analyses demonstrated that insertion (cathodic) and release (anodic) steps are quite equiv., which permits to consider this process as chem. reversible sequestration of carbon dioxide.
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Dates et versions

hal-01188187 , version 1 (25-11-2015)

Identifiants

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Viatcheslav Jouikov, Jacques Simonet. Cathodic carboxylation of gold in thick {Au-CO2}n layers. A model for reversible electrochemical sequestration of CO2. Electrochemistry Communications, 2015, 59, pp.40--42. ⟨10.1016/j.elecom.2015.06.020⟩. ⟨hal-01188187⟩
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