Electrochemical reduction of CO₂ to methanol over MWCNTs impregnated with Cu₂O

This study evaluated the reduction of CO₂ to methanol in the presence of effective and stable MWCNTs impregnated with Cu₂O. A preliminary DFT study shows that the incorporation of Cu₂O in MWCNTs improves the electronic properties of the electrocatalyst. The surface morphology and structural interaction between Cu₂O and MWCNTs at different Cu₂O loadings (10-50 wt%) were characterized by SEM, TEM, EDX, XRD, BET, TGA, and Raman spectroscopy. Characterization results show that the Cu₂O particles are incorporated at defect sites in the MWCNT matrix. However, higher lodgings (40 and 50 wt%) result in the agglomeration of Cu₂O particles and crystallite size growth. Electrochemical evaluation of the catalyst for CO₂ reduction was conducted in a two-component polycarbonate electrochemical cell. Linear sweep voltammetry results show that the 30% Cu₂O-MWCNTs catalyst gives the highest current density in the entire potential range, and a faradaic efficiency of 38% was achieved at -0.8 V for the reduction of CO₂ to methanol. The study shows that the impregnation of Cu₂O on MWCNTs affects the structural and electronic properties of the electrode, which in turn improves both the activity and stability of the catalyst as confirmed by chronoamperometry.