Multipolar Donor-Acceptor Conjugated Hypercrosslinked Polymers for Enhanced Visible-Light Photoreduction of CO₂ to CO

Multipolar donor-acceptor (D-A) hypercrosslinked polymers provide well-defined charge-transfer pathways that enable efficient and selective CO₂ photoreduction under visible light. While such systems hold promise for CO₂ conversion, achieving high activity, long-term stability, and product selectivity remains challenging. Here, we present HCP-CoTPP-Cz-1, a multipolar D-A hypercrosslinked conjugated polymer synthesized via Scholl coupling. HCP-CoTPP-Cz-1 exhibits a high CO₂ adsorption capacity of 9.71 wt% at 273 K, which is associated with cobalt-containing units incorporated within the polymer network. In addition, the extended π-conjugated D-A framework promotes efficient charge separation and charge-carrier transport. Under photocatalytic conditions employing [Ru(bpy)₃]Cl₂ as the photosensitizer and triethanolamine as the hole-sacrificial agent, HCP-CoTPP-Cz-1 achieves a CO evolution rate of 4402.5 µmol g^-1 h^-1 with an apparent quantum yield of 0.51% at 450 nm, representing a 37.5% enhancement compared with the non-D-A polymer HCP-CoTPP-s. Both catalysts maintain CO selectivity  >99%. Mechanistic studies reveal that the multipolar D-A architecture facilitates charge separation and transfer, suppresses electron-hole recombination, and enhances both CO₂ capture capacity and catalytic stability. By demonstrating a rational polymer design that enables efficient and stable CO₂ photoreduction, this work presents a feasible strategy to convert CO₂ into CO within green chemical production pathways.