Snow-like BiVO4 with rich oxygen defects for efficient visible light photocatalytic degradation of ciprofloxacin

Abstract

The overuse of ciprofloxacin (CIP), causing serious environment pollution, has drawn great attentions. To provide alternative solution to this problem, we synthesized a snow-like BiVO4 with rich oxygen vacancy by adjusting the amounts of cetyltrimethyl ammonia bromide (CTAB) surfactant. Various characterizations were performed to investigate the morphology and surface properties of the synthesized BiVO4. Interestingly, both the morphology and the amount of oxygen vacancy were related to the concentration of additional CTAB, and the most oxygen vacancies were generated when specific amount of CTAB (molar ratio of CTAB to Bi3+ of 0.2) was introduced. Photoluminescence and photoelectrochemical tests demonstrated that the presence of oxygen vacancy significantly enhanced the separation efficiency of photo-generated carriers in BiVO4. Subsequently, CIP photodegradation was significantly enhanced in the presence of snow-like BiVO4. Both quenching experiments and EPR tests demonstrated that photogenerated holes and •O2− were the main active species contributing to CIP degradation. Furthermore, CIP transformation pathway was proposed based on the identified transformation products. Our study developed a novel method to synthesize a BiVO4 material with snow-like morphology and abundant oxygen vacancy by simply varying the amount of surfactant. This study would shed light on designing the next generation photocatalyst with the assistant of surfactant to control the surface properties.