Advanced MnNi-P/ZIF8@CNT electrocatalyst for CO2 reduction: Achieving high efficiency, stability, and low energy demand

The electrochemical reduction of CO₂ into valuable products is a potential approach to reduce carbon emissions and meet energy concerns. Herein, we report the synthesis and use of MnNi-P/ZIF8@CNT, a composite electrocatalyst with high activity, selectivity, and stability for reducing CO₂ to CO. Structural and morphological characterizations using SEM, XRD, and Raman spectroscopy demonstrated that MnNi-P and ZIF8 are uniformly integrated on CNTs. Electrochemical techniques, including linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry, confirmed its high catalytic activity. MnNi-P/ZIF8@CNT exhibited a low onset potential of −355 mV (vs. RHE) and an overpotential of −616 mV at −8 mA cm⁻² in a 0.5 M KHCO₃ solution saturated with CO₂, outperforming ZIF8@CNT and MnNi-P@CNT. It achieved a high faradaic efficiency for CO (FE_CO) of over 93 % at −0.8 V (vs. RHE), surpassing many catalysts reported in the literature. Stability tests showed that MnNi-P/ZIF8@CNT maintained a stable current over 24 h without remarkable performance loss (<2 %), compared to 4.6 % and 8.4 % losses for ZIF8@CNT and MnNi-P@CNT, respectively. This work highlights the synergistic effects of MnNi-P and ZIF8, providing a robust platform for designing efficient, durable, and scalable catalysts for CO₂ electroreduction.