Photoelectrocatalytic CO₂ Reduction to Methanol by Molecular Self-Assemblies Confined in Covalent Polymer Networks

Inspired by the porous structures of photosynthetic organelles, we report here a new type of photoelectrode based on a standalone macroporous conjugated polymer network (MCN) that converts sunlight into high-energy electrons for CO₂ reduction to CH₃OH. The MCN provides supramolecular cavities with sufficient functional groups that control the structures of photocatalytic assemblies, which circumvents the geometric limitations of traditional inorganic counterparts. Stabilized interfacial contact between MCN and photocatalysts is achieved by strong chemical linkages throughout the network. Solar irradiation of MCN with a cobalt-based catalyst generates highly reducing electrons for the reduction of CO₂ to CH₃OH at a conversion efficiency of 70%. Production of CH₃OH sustains for at least 100 h, with a small decrease in yield rates. Scaling up the photoelectrode from 1 to 100 cm² results in photocurrent generation stabilized at 0.25 A and continuous CH₃OH production at a conversion efficiency of 85%, demonstrating the scalability and high performances.