Electro-Assisted Reduction of CO _\textrm2 to CO and Formaldehyde by (TOA) _\textrm6 [α-SiW _\textrm11 O _\textrm39 Co(\₎] Polyoxometalate: Electro-Assisted Reduction of CO _\textrm2 to CO and Formaldehyde
Résumé
We report here on the multiproton-multielectron electrochemical reduction of CO2 in homogeneous solution by using (TOA)6[α-SiW11O39Co(_)] (TOA = tetraoctyl ammonium; _ = vacant position in the coordination sphere of Co) as an electrocatalyst. First, the electrochemical behavior of (TOA)6[α-SiW11O39Co(_)] was analyzed in detail by cyclic voltammetry in dichloromethane, studying the influence of the presence of protons and/or CO2. These preliminary results were further used to optimize the conditions of electrolysis in terms of reduction potentials. Analysis of the electrolysis products in the gas and liquid phases show the formation of CO and HCHO without formation of H2. Our results tend to show that the (TOA)6[α-SiW11O39Co(_)] polyoxometalate is a catalyst for CO2 electroreduction, with unique selectivity.