Controllable morphology CoFe2O4/g-C3N4 p-n heterojunction photocatalysts with built-in electric field enhance photocatalytic performance.

CoFe 2 O 4 /g-C 3 N 4 p-n heterojunction photocatalysts have been successfully synthesized. The formation of p-n heterojunction and the unique morphology of g-C 3 N 4 enhanced electron transfer and charge separation, leading to a significant improvement in photocatalytic efficiency. 5-CoFe 2 O 4 /CNS not only had a high photocatalytic hydrogen evolution rate of 18.9 mmol·g−1·h−1, but also possessed an efficient photocatalytic fluoroquinolone antibiotics removal efficiency. A smaller band gap in 5-CoFe 2 O 4 /CNS photocatalyst promoted more light generated electrons under visible light irradiation. An internal electric field at the contact interface accelerated the accumulation of electrons and holes in the valence band of g-C 3 N 4 and conduction band of CoFe 2 O 4 , thereby revealing a higher separation efficiency and noticeable inhibited recombination rate of the photoinduced electrons and holes. Also, improved removal efficiency for fluoroquinolone antibiotics was attained in the self-designed acousto-optic microreactor, which was 7.2 and 30 times higher than quartz glass tube and batch experiment, respectively. [Display omitted] • The formation of p-n heterojunction with internal electric field showed an activity superior to individual constituents. • Photocatalytic activity of CoFe 2 O 4 /g-C 3 N 4 p-n heterojunctions was affected by composition ratio and morphologies. • The formation of p-n heterojunctions was associated with the morphology of g-C 3 N 4. • 5-CoFe 2 O 4 /CNS possessed a larger specific surface area, more photo-generated electrons, excellent separation efficiency • A novel acousto-optic microreactor further improved the removal efficiency with 30-fold higher than the batch experiment. [ABSTRACT FROM AUTHOR]