Conjugated cobalt-tetraphenylporphyrin hypercrosslinked polymers for efficient CO2 capture and selective photocatalytic reduction to CO

Abstract

The urgent need for sustainable CO₂ utilization drives the development of efficient photocatalytic systems for converting CO₂ into value-added chemicals. We report a novel cobalt-tetraphenylporphyrin-based hypercrosslinked polymer (HCP-CoTPP-DMB) synthesized via Friedel–Crafts alkylation using p-dimethoxybenzene as a conjugated crosslinker. This design yields a microporous architecture with enhanced CO₂ adsorption (10.1 wt% at 273 K) and accessible cobalt catalytic sites, coupled with an extended π-conjugated framework that promotes efficient charge transfer. Under visible-light irradiation with [Ru(bpy)₃]Cl₂ as a photosensitizer, HCP-CoTPP-DMB achieves an exceptional CO production rate of 3666.9 μmol g⁻¹ h⁻¹ with >99% selectivity, outperforming many reported porous organic polymers. The hierarchical pore structure and cobalt coordination synergistically enhance CO₂ capture and conversion, while the conjugated system ensures efficient charge separation. This work provides insights into designing conjugated polymer photocatalysts for selective CO₂ reduction, offering a scalable, cost-effective platform for sustainable CO production as a feedstock for green chemical synthesis.