Uniformly distributed anatase TiO2 nanoparticles on graphene: Synthesis, characterization, and photocatalytic application

• Uniform distributed TiO2 nanoparticles on graphene by a modified method.
• Reduced recombination rate of photogenerated electron–hole pairs.
• Effective charge transfer from TiO2 to graphene.
• Better photocatalytic activity upon UV and visible irradiation.
• A mechanism of bisphenol A degradation process is proposed.

Graphene (GR)/TiO2 nanocomposites are successfully synthesized using a simple and efficient hydrothermal method. Even-sized anatase TiO2 nanoparticles are uniformly distributed on GR. The GR/TiO2 nanocomposites exhibit an extended light absorption range and decreased electron–hole recombination rates. The photocatalytic activity of the as-prepared GR/TiO2 nanocomposites for bisphenol A (BPA) degradation is investigated under UV (λ = 365 nm) and visible (λ ⩾ 400 nm) light irradiation. The results show that GR/TiO2 nanocomposites have significantly higher photocatalytic activity than P25 (pure TiO2). The large increase in photocatalytic activity is mostly attributed to effective charge transfer from TiO2 nanoparticles to GR, which suppresses charge recombination during the photocatalytic process. After five successive cycles, the photodegradation activity of the GR/TiO2 nanocomposites shows no significant decrease, which indicates that the nanocomposites are stable under UV and visible light. X-ray photoelectron spectroscopy (XPS) is used to investigate the chemical bonds of GR/TiO2 nanocomposites before and after degradation to determine the degradation intermediate products of BPA under irradiation. A proposed degradation reaction pathway of BPA is also established. This study provides new insights into the fabrication and practical application of high-performance photocatalysts in wastewater treatment.