Promoted photocatalytic degradation and detoxication performance for norfloxacin on Z-scheme phosphate-doped BiVO4/graphene quantum dots/ P-doped g-C3N4

A novel kind of Z-scheme ternary heterojunctions phosphate-doped BiVO4/graphene quantum dots/P-doped gC3N4 (BVP/GQDs/PCN) were fabricated for the visible light degradation of norfloxacin (NOR), a typical antibiotic. Compared with binary type-II heterojunction phosphate-doped BiVO4/PCN (BVP/PCN), Z-scheme BVP/ GQDs/PCN exhibited promoted interfacial charge transfer efficiency and broadened visible light response range, endowing them with excellent photodegradation activity and mineralization ability in NOR degradation. A high NOR degradation rate of 86.3% with a removal rate of total organic carbon (TOC) of 55.8% can be achieved over BVP/GQDs/PCN for 120 min visible light irradiation, which is an excellent performance compared with ever reported similar photocatalysts. In particular, because of the enhanced redox ability of photogenerated charges and the generation of multiple active species (eg. center dot OH and center dot O2- ) over Z-scheme photocatalytic system, the accumulation of highly toxic degradation intermediates was greatly inhibited, and a better detoxication performance was obtained compared to PCN and BVP/PCN. This work may shed light on the inhibition of highly toxic degradation intermediates of antibiotics by regulating the charge transfer mechanism, photocatalytic active species, and the degradation pathway of antibiotics.

Automated summary

The novel Z-scheme ternary heterojunction BVP/GQDs/PCN demonstrated excellent visible light photocatalytic activity and NOR degradation performance, outperforming traditional binary heterojunctions.