CO2 conversion to synthetic fuels using flow cell reactor over Cu and Ag based cathodes

Abstract

As a result of electrochemical conversion of carbon dioxide (CO₂), value-added chemicals like as synthetic fuels and chemical feedstocks can be produced. In the current state of the art, copper-based materials are most widely used being the most effective catalysts for this reaction. It is still necessary to improve the reaction rate and product selectivity of CuOx for electrochemical CO₂ reduction reaction (CO₂RR). The main objective of this work was synthesized and evaluate the copper oxide electrocatalyst combined with silver (CuO 70% Ag 30%) for the conversion of carbon dioxide into synthetic fuels. The catalysts have been prepared by the oxalate method and assessed in a flow cell system. The results of electrochemical experiments were carried out at room temperature and at different potentials (-1.05 V–0.75 V vs. RHE in presence of 0.1 M KHCO₃) and gas and liquid chromatographic analysis are summarized. The CuOx-based electrodes demonstrated the selective of ~ 25% at -0.55 V for formic acid (HCOOH) and over CuO -Ag and selective of ethylene at ~ 20% over CuOx at -1.05 V. Other products were formed as ethylene, ethanol, and propanol (C₂H₄, EtOH, PrOH) at more positive potentials. On the other hand, carbon monoxide, acetate, ethylene glycol, propinaldehyde, glycoaldehyde and glyoxal (CO, CH₃COO, C₂H₆O₂, C₃H₆O, C₂H₄O₂, C₂H₂O₂) have been formed and detected. Based on the results of these studies, it appears that the formation of synthetic fuels from CO₂ at room temperature in alkaline environment can be very promising.