Ultra-stabilized Cu2 + sites in conductive MOF/t-Cu2O interface for benchmark CO2 reduction

Developing and retaining the highly charged copper (Cu) site during electrochemical CO₂ reactions (CO₂RR) is critical but challenging. Herein, ultrastable Cu²⁺ sites in conductive metal-organic framework (cMOF)/t-Cu₂O heterostructure are reported to boost the selectivity and stability for CO₂RR towards C2 products. Due to the epitaxial conjugated cMOF with strong electron acceptor property, the accumulation of electrons is evacuated during CO₂RR timely, tightly confining and protecting the highly charged Cu²⁺ site at the cMOF/t-Cu₂O interface. In-situ spectra and theoretical calculations verify that Cu²⁺ sites at the interface facilitate a more favorable hydrogenated route from *COH to *CO*COH with the low-energy pathway. Semi-situ X-ray absorption spectroscopy and high-angle annular dark-field imaging confirm the ultra-long stability of the highly charged Cu²⁺ sites during CO₂RR. Optimized cMOF/t-Cu₂O achieves significant Faradaic efficiency (FE) for C2 products of 79.3 % with current density of −440 mA·cm⁻² and demonstrates ultra-long stability over 40 hours in flow cell, which is superior to nearly all reported MOFs and Cu₂O-based catalysts, ranking it one of the best-performing Cu-based catalysts.