Interface-Engineered AgMOF/Cu₂O Pyramids for Enhanced C₂H₄ Selectivity in Electrochemical CO₂ Reduction

Cu-based catalysts are widely explored for electrochemical CO₂ reduction (eCO₂RR), but their application is limited by high overpotentials, poor selectivity, and stability issues. To address these challenges, we report the design of AgMOF/Cu₂O pyramid heterostructure catalysts with (111) lattice fringes, engineered lattice distortions, and abundant oxygen vacancies that effectively anchor Cu𝛿⁺ domains. Structural features at the AgMOF/Cu₂O interface provide rapid electron transfer pathways, as confirmed by in situ ATR-FTIR measurements and theoretical simulations, thereby enhancing catalytic efficiency without requiring sacrificial agents. Moreover, the asymmetric interfacial sites with distinct charge distributions promote C-C coupling by stabilizing the ^*COCO intermediate, which drives the selective conversion of CO₂ into ethylene (C₂H₄). Density Functional Theory (DFT) calculations further demonstrate that the heterostructure enhances CO₂ adsorption and lowers the energy barriers for key intermediates, establishing a favorable thermodynamic landscape for multi-step reduction. Consequently, the optimized AgMOF/Cu₂O catalyst achieves a remarkable Faradaic efficiency of 61% for C₂H₄ production at -1.1 V vs. RHE. These findings highlight that the synergistic interface engineering and charge-polarized metal sites in AgMOF/Cu₂O heterostructures provide a promising strategy for advancing efficient CO₂ electrolysis toward valuable multi-carbon products.