Soluble polyfluorene dots as photocatalyst for light-driven methylene blue degradation and hydrogen generation

Abstract

Recently, polymer dots (Pdots) possessing conjugated structures have attracted the attention of researchers for use as photocatalysts for H₂ evolution reactions. Herein, soluble Pdots (ca. 30 nm) based on the semiconducting polymer poly(9,9-dioctylfluorene) (PFO) were introduced as a photocatalyst for photodegradation activity and light-driven hydrogen generation by a nanoprecipitation method. A photodegradation activity study of these Pdots (PFO-Pdots) with methylene blue (MB) showed a good ability to degrade MB in aqueous solution under simulated light. Moreover, the PFO-Pdots exhibited a good H₂ 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 a significant photocurrent of the PFO-Pdots was generated under light irradiation. The low recombination rate of the photogenerated carriers and shortened charge diffusion path led to a good photocatalytic H₂ evolution rate. These phenomena suggested that the conjugated Pdots only composed of C, H, and O elements had good photocatalytic activity, and it was a powerful supplement to existing polymer photocatalytic systems. Moreover, PFO-Pdots had better photocatalytic activity in water than pure PFO. This study shows that PFO-Pdots or conjugated Pdots may be promising candidates in the field of photocatalysis in the future.