Analysis of carbon dioxide-to-methanol direct electrochemical conversion mediated by an ionic liquid

• An intensified CO2 capture and electro-conversion process was proposed and analyzed.
• An Ionic Liquid (IL) was synthesized and used as absorption media and electrolyte.
• The IL gives high ionic conductivity and acts as charged intermediate stabilizer.
• Specific electrochemical energy consumption was estimated to be 8.683 kWh kg (CO2)−1.

An intensified process for carbon dioxide capture and conversion is proposed and analyzed, considering an electrochemical parallel plate reactor which processes a CO2-charged stream from an absorption unit at 40 °C and atmospheric pressure and where the target product of the conversion is methanol.The task-specific ionic liquid 1-(3-aminopropyl)-3-methylimidazolium bromide was selected, synthesized and characterized. This ionic liquid has shown a good absorption capacity, high ionic conductivity, high chemical–electrochemical stability and acts as a charged intermediate (CO2*−) stabilizer, enabling the electrochemical reduction of absorbed CO2.The electrical energy in the electrochemical reactor was estimated to be 8.683 kWh kg (CO2)−1 or 115.16 g (CO2) kWh−1, too high to ensure the environmental sustainability of the process. A low concentration of carbon dioxide in the liquid phase, at ambient conditions, implies the need for a high electrode area for the process and is a major hindrance to improving the economy of the process.