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Electroreduction of Carbon Dioxide on Copper-Based Electrodes: Activity of Copper Single Crystals and Copper-Gold Alloys

par Christophe, Jennifer ;Doneux, Thomas ;Buess Herman, Claudine
Référence Electrocatalysis, 3, 2, page (139-146)
Publication Publié, 2012

Article révisé par les pairs

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Résumé :

The activity of copper single-crystal and copper-gold alloyed (Au 1Cu 99, Au 10Cu 90, Au 20Cu 80, Au 50Cu 50) electrodes for CO 2 electroreduction has been investigated in aqueous phosphate buffer solutions by cyclic voltammetry and potentiostatic long-term electrolysis. In addition to H 2, four species were identified in the gaseous phase by chromatography after electrolyses: CO, CH 4, C 2H 4 and traces of C 2H 6. At copper electrodes, the major carbon-containing products are CO and CH 4. Analysis of the data indicates that the fraction of methane increases in the order Cu (poly) < Cu (100) < Cu (111), whereas a concomitant decrease of the carbon monoxide fraction is observed. The selectivity of low-index faces towards methane formation is consistent with a mechanism involving CO(ads) and H(ads). Analytical information obtained after potentiostatic electrolyses at copper-gold alloys shows that the CO production increases markedly with the Au content, while the fraction of CH 4 diminishes. Amongst all the examined electrodes, the Au 50Cu 50 alloy appears to be the most efficient substrate for the conversion of CO 2 into carbon-containing gaseous products. © 2012 Springer Science+Business Media, LLC.