Electrocatalytic conversion of CO2 to added-value chemicals in a high-temperature proton-exchange membrane reactor

Abstract

We have developed a novel gas-phase electrocatalytic system for the conversion of CO2 into added-value chemicals. The system is based on a high-temperature proton-exchange membrane reactor containing a Cu cathodic catalyst supported on carbon nanofibers (CNFs) and an H3PO4-doped polybenzimidazole polymer electrolyte membrane (PBI). The resulting Cu–CNFs/PBI/IrO2 membrane electrode assembly (MEA) allowed the utilization of higher temperatures (110 °C) than has been previously reported. The application of a low current density (−0.8 mA/cm2) permitted the direct transformation of CO2 into various organic compounds in the C1–C3 range, acetaldehyde being the most common product (85% selectivity). The application of a higher current density (−1.6 mA/cm2) increased the overall electrocatalytic activity of the system, producing lighter and more saturated compounds. The novel electrochemical cell proposed in this work allows the conversion of CO2 into valuable products under mild conditions (i.e., room pressure, 110 °C) with no requirement for H2 and using electrical energy that could potentially be obtained from renewable energy sources.