Interfacial Engineering of ZIF‐67@Ti 3 C 2 T x MXene Hybrids for Selective Electrochemical CO 2 Reduction to C 1 Products

ABSTRACT Electrochemical CO 2 reduction (CO 2 RR) enables conversion of CO 2 into fuel‐relevant products using renewable electricity, but aqueous systems are often limited by hydrogen evolution reaction (HER) and mass‐transport constraints. Here, a ZIF‐67@Ti 3 C 2 T x MXene hybrid electrocatalyst is prepared via in situ growth of cobalt‐based ZIF‐67 nanoparticles on conductive Ti 3 C 2 T x sheets synthesized using a mild LiF/HCl etching route. The catalytic performance is systematically evaluated in both H‐cell and gas‐fed flow‐cell configurations. Among the investigated compositions (15, 30, and 45 wt.%), ZIF(30%)@Ti 3 C 2 T x provides the most favorable balance between conductivity and accessible catalytic site density. Under gas‐fed flow‐cell operation, ZIF(30%)@Ti 3 C 2 T x reaches its highest CO 2 RR selectivity at −0.8 V vs RHE, delivering ∼84% total Faradaic efficiency toward carbon‐containing products (dominated by methane and methanol) while maintaining stable performance over 10 h of continuous electrolysis. In comparison, ZIF‐67 requires a more negative potential to reach its best performance and exhibits lower carbon‐product selectivity due to stronger competition from HER. These results highlight how MOF–MXene interfacial engineering, together with a flow‐cell configuration, can improve charge transport and active‐site utilization to enhance aqueous CO 2 electroreduction selectivity and stability.