Electrolytic CO₂ Reduction in Tandem with Oxidative Organic Chemistry

Abstract

Electrochemical reduction of CO2 into carbon-based products using excess clean electricity is a compelling method for producing sustainable fuels while lowering CO2 emissions. Previous electrolytic CO2 reduction studies all involve dioxygen production at the anode, yet this anodic reaction requires a large overpotential and yields a product bearing no economic value. We report here that the cathodic reduction of CO2 to CO can occur in tandem with the anodic oxidation of organic substrates that bear higher economic value than dioxygen. This claim is demonstrated by 3 h of sustained electrolytic conversion of CO2 into CO at a copper–indium cathode with a current density of 3.7 mA cm–2 and Faradaic efficiency of >70%, and the concomitant oxidation of an alcohol at a platinum anode with >75% yield. These results were tested for four alcohols representing different classes of alcohols and demonstrate electrolytic reduction and oxidative chemistry that form higher-valued carbon-based products at both electrodes.

CO2 reduction on gas-diffusion electrodes and why catalytic performance must be assessed at commercially-relevant conditions

“…More importantly, the reaction will not be hindered by a deficit of CO 2 , even at higher local pH conditions. While single-carbon CO 2 reduction products such as CO, 89 HCOOH 90,91 and CH 4 92 can reach relatively high selectiv-…”

“…targeting lower overall cell potentials by improving other parts of the conversion unit, [2][3][4][5] while looking to more efficiently integrate electrochemical CO 2 conversion units with upstream and downstream processes. 6 Future devices will also need to demonstrate stable long-term operation (420 000 hours) at substantial current densities (4200 mA cm À2 ) to minimize the capital-expenditure of a conversion unit to economicallycompelling levels.…”

Visible Light–Driven Cascade Carbon–Carbon Bond Scission for Organic Transformations and Plastics Recycling

“…Plastics based on the polyethylene backbone, such as polypropylene and polystyrene, have unfortunately proliferated and become recalcitrant wastes that pollute the oceans. [64][65][66] As a model substrate for polyethylene, we selected a long-chain alcohol, 1-hexadecanol (36). Due to its poor solubility in acetonitrile at room temperature, 36 had to be heated to 55 °C during the reaction to allow full dissolution.…”

“…This concept had been pioneered by Meyer and co-workers, who demonstrated its potential for chloride [25] and benzyl alcohol oxidation with simultaneous H 2 evolution. [26] Others, including Sun and co-workers, [27][28][29][30] Meyer and co-workers, [31][32][33][34][35] Berlinguette and co-workers, [36][37][38] Reisner and co-workers, [14,[39][40][41] and Lei and co-workers, [42][43][44] have subsequently shown that the gap between AP and radical catalysis can potentially be bridged via the valorization of biomass, functionalization of amines, oxidation of other halides, photo-electrochemical reduction of CO 2 , and even photoreforming of plastics.…”

“…Cascade CC bond cleavage in macromolecular hydroxyl functionalized biodegradable(34)(35)(36) and non-biodegradable (37 and 38) polymers. In all the polymeric substrates, the sites of CC bond cleavage are highlighted in red, with multiple red colored CC bonds indicating the cascade shortening of the polymer chain.…”