Dual electron reservoirs: Synergistic photocatalytic degradation of antibiotics by oxygen vacancy-rich BiOBr nanoflowers and magnetic carbon nanotubes

Abstract

Rational modulation of surface oxygen vacancies (OVs) and efficient charge separation are important factors for improving solar energy conversion efficiency. However, the synergistic relationship between OVs and magnetic carbon nanotubes (The magnetic carbon nanotubes in this paper are abbreviated as CNFe) is still unclear. As a result, oxygen vacancy-rich BiOBr/CNFe photocatalysts were created in this study by in situ growing OVs-BiOBr on bamboo-shaped CNFe. The formation of oxygen vacancies introduced a defect band where electrons could directly transition to the oxygen vacancies for storage, suppressing the recombination of photoinduced charge carriers. Meanwhile, CNFe acted as an electronic bridge to rapidly transfer electrons from the conduction band of BiOBr to CNFe, thus retaining the powerful redox-capable photogenerated carriers and significantly improving the photocatalytic activity. As a result, the synthesised OVs-BiOBr/CNFe (O-BCN) photocatalyst exhibited 80.8 % degradation of lomefloxacin hydrochloride within 3 h, with an apparent rate constant 4.4 times higher than BiOBr. This work provides new insights into the preparation of efficient photocatalysts by regulating surface defects and bridging effects.