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

CoFe2O4/g-C3N4 p-n heterojunction photocatalysts have been successfully synthesized. The formation of p-n heterojunction and the unique morphology of g-C3N4 enhanced electron transfer and charge separation, leading to a significant improvement in photocatalytic efficiency. 5-CoFe2O4/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-CoFe2O4/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-C3N4 and conduction band of CoFe2O4, 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.