Strategies to activate conjugated polymers by molecular catalysts for light-driven CO2 conversions

Photocatalytic small-molecule conversion by harnessing sunlight energy is of interest because of its potential to achieve artificial photosynthesis. This review explores the potential of conjugated polymers as CO 2 reduction photocatalysts and highlights their unique molecular-level designs. Following the basic design principles of conventional metal complexes and semiconductor photocatalysts, the specific photocatalyst designs developed for conjugated polymers are summarized. This review further covers intermolecular hybridization with metal complexes and built-in approaches for site-selective catalyst incorporation, highlighting the importance of precisely tuning the energy levels for direction-selective photoinduced charge transport within both intermolecular and built-in hybrid photocatalysts to improve photocatalytic efficiency. Understanding and utilizing the characteristic features of molecular-based photocatalyst materials, including conjugated polymers, that enable molecular-level functional integration will facilitate the development of artificial photosynthetic reactions. • The potentials of conjugated polymers as CO 2 reduction photocatalysts are explored. • The basic principles of photocatalyst materials and important notes for evaluating their photocatalytic performance are briefly summarized. • The design principles of intermolecular hybridization and built-in approaches to incorporate metal complex catalysts in conjugated polymers were highlighted.