Efficient visible-light induced electron-transfer in z-scheme MoO3/Ag/C3N4 for excellent photocatalytic removal of antibiotics of both ofloxacin and tetracycline

A novel Z-scheme MoO3/Ag/C3N4 composite catalyst is presented that can be constructed by simple and reliable hydrothermal and borohydride reduction methods. The catalyst exhibits excellent visible-light photocatalytic activity in degrading ofloxacin, as evidenced by more than a threefold increase in the rate of degradation compared to the catalysts with only Ag or MoO3 alone on C3N4. Scavenger reactions suggest that hydroxyl and superoxide radicals are the major reactive species for the catalytic process. The hydroxyl radical generation in the MoO3/Ag/C3N4 catalyst is aided by Ag nanoparticles, acting as a mediator of fast charge transfer through MoO3 and C3N4. The MoO3/Ag/C3N4 catalyst, whose performance in terms of a measure of performance utilized here exceeds that of one of the best photocatalysts for the degradation of ofloxacin, also outperforms one of the best photocatalysts for the removal of the other major type of antibiotic of tetracycline.