CO2 -Triggered Switchable Hydrophilicity of a Heterogeneous Conjugated Polymer Photocatalyst for Enhanced Catalytic Activity in Water

Abstract

Water compatibility for heterogeneous photocatalysts has been pursued for energy and environmental applications. However, there exists a trade-off between hydrophilicity and recyclability of the photocatalyst. Herein, we report a conjugated polymer photocatalyst with tertiary amine terminals that reversibly binds CO₂ in water, thereby generating switchable hydrophilicity. The CO₂ -assisted hydrophilicity boosted the photocatalytic efficiency in aqueous medium with minimum dosage. When CO₂ was desorbed, the photocatalyst could be simply regenerated from reaction media, facilitating the repeated use of photocatalyst. Hydrophilicity/hydrophobicity control of the polymer photocatalyst was successfully showcased through a variety of organic photoredox reactions under visible-light irradiation in water.

Keywords: carbon dioxide; conjugated polymers; heterogeneous catalysis; photocatalysis; photoredox chemistry.