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.