Soluble Polyfluorene Dots as Photocatalyst for Light-Driven Methylene Blue Degradation and Hydrogen Generation

Recently, polymer dots (Pdots) possess conjugated structures have attracted the attention of researchers as photocatalysts for H2 evolution reaction. Herein, a soluble Pdots (ca. 30 nm) based on the semiconducting polymer poly(9, 9-dioctylfluorene) (PFO) were introduced as a photocatalyst towards photodegradation activity and light-driven hydrogen generation by nanoprecipitation method. Through the photodegradation activity study of this Pdots (PFO-Pdots) with methylene blue (MB), it showed good degradation ability to MB in aqueous solution under simulated light. Moreover, the PFO-Pdots exhibited a good hydrogen production rate up to 1.20 ± 0.04 mmol h-1 g-1 without platinum or rhodium as a cocatalyst. According to the I-V curves and transient photocurrent response study, it was obvious that the significant photocurrent of the PFO-Pdots was generated under light irradiation. The low recombination rate of photogenerated carriers and shortened charge diffusion path led to the good photocatalytic H2 evolution rate. These phenomena suggested that the conjugated polymers dots only composed of C, H, and O elements had good photocatalytic activity, and it was a powerful supplement to the existing polymer photocatalytic system. Moreover, PFO-Pdots had better photocatalytic activity in water than pure PFO. This study shows that PFO-Pdots or conjugated polymer dots may be a promising candidate in the field of photocatalysis in the future.