Enhanced tetracycline degradation and electricity generation by persulfate in a photocatalytic fuel cell with a ternary Z-scheme photoanode

The practical application of a photocatalytic fuel cell (PFC) is usually limited by its long pollutant degradation period. Here, two strategies were adopted to improve the PFC performance. On one hand, a ternary Z-scheme heterojunction photocatalyst (Bi2O4/Bi2WO6/C3N4qds) was used as the photoanode to promote the separation of photo-generated charge carriers, thereby improving the photocatalytic process. On the other hand, CuFe2O4 was used as the photocathode to activate persulfate (PS) to further enhance pollutant degradation and electricity generation. The results indicated that, under visible light irradiation (45 min), the degradation efficiency of tetracycline by the coupling system of Bi2O4/Bi2WO6/C3N4qds-CuFe2O4 + PS (PFCps) reached to 94.5%. The corresponding first-order kinetic constant was 8.13, 3.40, 3.34, and 1.89 times that of PS, Bi2O4/Bi2WO6/ C3N4qds + PS, CuFe2O4 + PS, and Bi2O4/Bi2WO6/C3N4qds-CuFe2O4, respectively. The highest maximum power density of the PFCps system was 37.0 mu W center dot cm 2, which was 1.89 times that of the PFC of Bi2O4/Bi2WO6/C3N4qdsCuFe2O4. The reactive species capturing experiments verified that center dot OH, center dot O2- , h+, and center dot SO4- had positive effects on the tetracycline degradation. In addition, the mechanism involved in the PFCps system was proposed. This work provided a novel idea for the development of coupling technologies to treat antibiotic wastewater.