Conjugated polymer dots/graphitic carbon nitride nanosheet heterojunctions for metal-free hydrogen evolution photocatalysis

Abstract

Graphitic carbon nitride (g-C₃N₄)-based heterojunctions have been widely applied to photocatalytic hydrogen evolution. However, most of the g-C₃N₄-based heterojunctions still require the incorporation of noble metal co-catalysts for hydrogen evolution. Based on the excellent prolonged excited state lifetime, tunable optical properties, appropriate bandgap of conjugated polymer dots (Pdots) and unique few-layered g-C₃N₄ nanosheets with porous structures, in this study, polyfluorene Pdots are facilely coupled with g-C₃N₄ nanosheets to form organic heterojunctions. The poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) Pdots/g-C₃N₄ nanosheet heterojunctions can significantly extend the light-absorption range and promote the electron–hole pair separation, leading to an enhanced hydrogen evolution rate up to 929.3 μmol h⁻¹ g⁻¹ with an apparent quantum yield of 5.7% at 420 nm without any metallic co-catalyst. This approach can provide a facile and operable fabrication technique for high performance photocatalysts, optical sensors and photoelectric devices in a sustainable way.