Electrocatalytic conversion of CO sub(2) to produce solar fuels in electrolyte or electrolyte-less configurations of PEC cells

• Published in: Faraday discussions 2015-12, Vol.183, p.125-145
• Main Authors: Ampelli, C, Genovese, C, Marepally, B C, Papanikolaou, G, Perathoner, S, Centi, G
• Format: Article
• Language: English
• Subjects: Carbon black; Carbon dioxide; Electrodes; Electrolytes; Electrolytic cells; Liquids; Productivity; Reduction (electrolytic)
• ISSN: 1359-6640; 1364-5498
• DOI: 10.1039/c5fd00069f

The electrocatalytic reduction of CO sub(2) is studied on a series of electrodes (based on Cu, Co, Fe and Pt metal nanoparticles deposited on carbon nanotubes or carbon black and then placed at the interface between a Nafion membrane and a gas-diffusion-layer electrode) on two types of cells: one operating in the presence of a liquid bulk electrolyte and the other in the absence of the electrolyte (electrolyte-less conditions). The results evidence how the latter conditions allow productivity of about one order of magnitude higher and how to change the type of products formed. Under electrolyte-less conditions, the formation of >C2 products such as acetone and isopropanol is observed, but not in liquid-phase cell operations on the same electrodes. The relative order of productivity in CO sub(2) electrocatalytic reduction in the series of electrodes investigated is also different between the two types of cells. The implications of these results in terms of possible differences in the reaction mechanism are commented on, as well as in terms of the design of photoelectrocatalytic (PEC) solar cells.