Hydrothermal synthesis of Step-scheme layer g-C3N4/columnar ZnZrO3 heterojunction photocatalyst toward efficient norfloxacin degradation under solar light

Based on the current sewage dilemma caused by the abuse of broad-spectrum antibiotics, how to remove these antibiotic pollutants (such as Norfloxacin) reasonably and effectively in natural waters is urgent. Herein, a novel Step-scheme g–C3N4–ZnZrO3 (S-scheme, CN-ZZO) heterojunction photocatalysts were synthesized by ultrasonic assisted hydrothermal method, and g-C3N4 (CN) as a self-sacrificing material provides the anchoring platform for ZnZrO3 (ZZO). All the samples were tested toward photocatalytic activity of Norfloxacin (Nor) degradation, and g–C3N4–30%ZnZrO3 (CN-30ZZO) was identified as the finest catalyst to effectively degrade 96 % norfloxacin after 180 min of solar light exposure and stably operate at pH = 7.0 within 5 consecutive runs. Finally, by compared the difference of charge transfer paths and synergistic effect between the heterojunction interfaces of CN and ZZO in the type-ii scheme mechanism and S-scheme, and verified the quenching experiment results (h+-dominated role), it is deduced that CN-ZZO heterojunction belongs to the S-scheme mechanism with stronger photo-redox performance, longer carriers’ lifetime, and more feasible migration pattern. The efficient photocatalytic degradation of Norfloxacin by g-C3N4–ZnZrO3 photocatalyst attributed to the S-scheme heterojunction. [Display omitted] •A Step-scheme layer g-C3N4/columnar ZnZrO3 heterojunction photocatalyst was prepared by ultrasonic hydrothermal route.•The g–C3N4–30%ZnZrO3 heterojunction photocatalyst exhibited splendid photocatalytic activity of norfloxacin under solar light.•Synergistic catalytic effect between layer g-C3N4 and columnar ZnZrO3 has been explained.•Two possible type-ii scheme mechanism and S-scheme for g–C3N4–ZnZrO3 heterojunction were deduced to prove that the S-scheme carriers transfer mechanism with improved photoactivity is reasonable and excellent.