Studies on Degradation of Copper Nano Particles in Cathode for CO2 Electrolysis to Organic Compounds

• Cu nano particles used as cathode for CO2 gas electro-reduction to organics.
• Overall faradaic efficiency is 39.6% and HER suppressed to 4.5%.
• Faradic efficiency decreases due to cathode degradation after 50 min electrolysis.
• Cu particle depletion from cathode is the reason for reduced efficiency.

In the present work, copper nanoparticles are used in cathode electrode and Pt/C in anode electrode of an electrolysis cell for gas phase electroreduction of CO2 using Nafion 117 as electrolyte. The product analysis of electro-reduction process carried out in HPLC and mass spectroscope reveals formation of carbon monoxide, methane, methanol and ethane along with hydrogen as the major product and traces of C2, C3 alcohols and ketones. Overall faradaic efficiency corresponding to CO2 reduction product is 39.6%, whereas hydrogen production is suppressed to 4.5% till the ERC operation of 50 minutes. Thereafter efficiency of ERC decreases and hydrogen evolution increases. SEM, EDS and XRD studies of cathode electrodes points out that depletion of CO2 reduction to CO and CH4 products with time may be due to dissolution of Cu nano particles from the cathode electrode.