Single-Crystal Metal–Organic and Covalent Organic Framework Hybrids Enable Efficient Photoelectrochemical CO₂ Reduction to Ethanol

Multicarbon alcohols produced through photochemical and electrochemical CO₂ reduction reactions (CO₂RR) are promising alternatives to fossil fuels; however, their selectivity and efficiency remain low due to the high energy barrier for C-C coupling and the competition from hydrocarbon production. Here, we present a strategy to enhance ethanol efficiency and selectivity via cooperative catalysis in porous structures for photoelectrochemical (PEC) CO₂RR. Using a coordination-templated strategy, we synthesized single crystals of MOF-COF (MOCOF) hybrids with metalloporphyrins, with their structures determined by single-crystal 3D electron diffraction. The porous frameworks featuring adjacent confined metalloporphyrins efficiently capture and cooperatively activate CO₂, achieving outstanding PEC CO₂-to-ethanol conversion. Particularly, the Pt-MOCOF delivers a Faradaic efficiency (FE) of 83.5% at -1.0 V with 91.7% carbon selectivity, surpassing state-of-the-art COF or MOF catalysts and ranking it among the top-performing catalysts. The catalyst system displays remarkable stability, maintaining 95% of its activity after 100 h of continuous operation. Experiments and theoretical calculations revealed that the cooperative catalyst enriches and stabilizes intermediates in the channels, guiding the reaction pathway toward ethanol production.