Molecular to Porous-Polymeric Translation of Cobalt-Terpyridine Motif Enables Charge-Carrier Engineering for Highly Selective CO ₂ Photoreduction

Designing efficient catalysts from molecular precursors remains a fundamental issue in photoassisted CO2 reduction. Herein, we demonstrate that polymerization of a presynthesized cobalt-terpyridine complex yields a π-conjugated porous polymer (Co@Te-POP) that exhibits a 3500 μmol g−1 CO production with notable selectivity, outperforming both the molecular analogue and metal-free polymer. It has been observed that polymerization of the well-defined ligand complex benefits the material with enhanced light harvesting, extended charge delocalization, prolonged carrier lifetimes, and accelerated interfacial electron transfer, thereby boosting the photocatalytic performance. Femtosecond transient absorption spectroscopy analysis reveals noticeably prolonged charge-carrier lifetimes upon polymerization, establishing a kinetic basis for efficient electron transfer to Co sites. Operando surface-enhanced Raman spectroscopy provides insights into CO2 activation and key reaction intermediate formation, while density functional theory studies highlight the preferential carbon dioxide reduction reaction (CO2RR) pathway. These findings establish molecular-to-polymeric translation as an effective strategy for charge-carrier engineering and provide fundamental insight into structure−property performance relationships and their underlying mechanisms in heterogeneous CO2RR.