In recent years, human activities have led to an unprecedented rise in atmospheric CO2 levels, causing significant environmental challenges. To combat this issue, there’s growing interest in the conversion of CO2 into valuable chemicals. This study reports the synthesis and electrocatalytic evaluation of CexOy/ZIF-zni catalysts for CO2 reduction. The catalyst exhibited remarkable selectivity to CO, achieving excellent Faradaic efficiency (FE) of 87.7 % at an overpotential of 170 mV. The findings revealed that by adjusting the applied potential during electrolysis, it was possible to tune the catalyst's electronic properties. This resulted in a reduced overpotential and a lower CO onset potential of − 300 mV. Density functional theory (DFT) calculations revealed that the synergistic interaction between the oxygen of CexOy and the Zn ion of the ZIF-zni, exposes cerium as the active site for CO2 activation. This interaction also stabilizes the crucial *COOH intermediate, facilitating the electrochemical CO2 reduction reaction.