Enhanced photoelectrocatalytic degradation of bisphenol a by BiVO photoanode coupling with peroxymonosulfate.

Peroxymonosulfate (PMS) was introduced into a photoelectrocatalytic (PEC) system with a bismuth vanadate (BiVO) photoanode to enhance the PEC oxidation of bisphenol A (BPA). With the addition of 5 mM PMS, the degradation efficiency of 10 mg/L BPA was significantly improved from 24.2% to 100.0% within 120 min and the side reaction of O evolution was avoided at a potential as low as 0.25 V. The electron spin resonance and radicals quenching results suggested that photogenerated holes instead of SO and OH were primarily responsible for the BPA degradation. To further explore the role of PMS, a photocatalytic fuel cell with the structure of BiVO (photoanode)|10 mg/L BPA|proton exchange membrane (separator)|5 mM PMS|Pt (cathode) was constructed and demonstrated that PMS played a key role as electrons acceptor instead of the precursor of SO. The PEC tests including open-circuit potential, linear sweep voltammetry and electrochemical impedance spectroscopy indicated that a more efficient separation of photogenerated charges was achieved in the PEC process with the help of PMS, thus generating more photogenerated holes for enhanced BPA degradation. This work may provide a novel way to enhance the separation of photogenerated charges at the photoanode.