Efficient Crystallization of Conjugated Microporous Polymers to Boost Photocatalytic CO2 Reduction

Abstract

The use of conjugated microporous polymers (CMPs) in photocatalytic CO₂ reduction (CO₂RR), leveraging solar energy and water to generate carbon-based products, is attracting considerable attention. However, the amorphous nature of most CMPs poses challenges for effective charge carrier separation, limiting their application in CO₂RR. In this study, we introduce an innovative approach utilizing donor π-skeleton engineering to enhance skeleton coplanarity, thereby achieving highly crystalline CMPs. Advanced femtosecond transient absorption and temperature-dependent photoluminescence analyses reveal efficient exciton dissociation into free charge carriers that actively engage in surface reactions. Complementary theoretical calculations demonstrate that our highly crystalline CMP (Py-TDO) not only greatly improves the separation and transfer of photoexcited charge carriers but also introduces additional charge transport pathways via intermolecular π–π stacking. Py-TDO exhibits outstanding photocatalytic CO₂ reduction capabilities, achieving a remarkable CO generation rate of 223.97 μmol g⁻¹ h⁻¹ without the addition of chemical scavengers. This work lays pioneering groundwork for the development of novel highly crystalline materials, advancing the field of solar-driven energy conversion.