A Type-II CQDs regulating FeOOH decorated BiVO4 photoelectrode for highly efficient photoelectrochemical degradation of tetracycline

[Display omitted] •A type-II FeOOH-CQDs/BiVO4 photoelectrode was successfully fabricated.•FeOOH-CQDs/BiVO4 exhibited excellent PEC degradation performance towards TC.•The type-II heterojunction facilitated the charge separation over BiVO4.•CQDs would regulate the growth of FeOOH and mediate the charge transfer.•The PEC degradation mechanism of TC over FeOOH-CQDs/BiVO4 was revealed. Bismuth vanadate (BiVO4) photoelectrode is of great potentials to be used for photoelectrochemical (PEC) removal of antibiotic pollutant. However, it still suffers from lower efficiency. Herein, a type-II FeOOH-CQDs/BiVO4 photoelectrode was fabricated via the in-situ growth of FeOOH nanoparticles over BiVO4 using Carbon quantum dots (CQDs) as mediator. Benefiting from the type-II heterojunction between BiVO4 and FeOOH, as well as the excellent charger transfer assisted by CQDs, FeOOH-CQDs/BiVO4 exhibited excellent PEC degradation performance towards a typical antibiotic- tetracycline (TC). In a typical PEC process, FeOOH-CQDs/BiVO4 photoelectrode (2 cm × 2 cm) yielded a high removal ratio of ∼ 99 % toward TC within 120 min at an applied potential of 0.6 V (vs. Hg/Hg2Cl2). Moreover, the PEC configuration was verified to be used for TC degradation in actual waters, such as tap water and lake water, with > 90 % of removal ratio. The radical trapping experiments revealed holes and superoxide radical dominated in the TC degradation process. This work provides an insight on the type-II heterojunction photoelectrode to enhance the PEC degradation of TC, which would help for the treatment of antibiotic wastewater.