Synergistic activation of photocatalysis and peroxymonosulfate via Fe2O3/Bi2O3 p-n heterojunction for enhanced degradation of tetracycline

In this study, Fe 2 O 3 /Bi 2 O 3 p-n heterojunction photocatalysts were fabricated to remove tetracycline (TC). The Fe 2 O 3 /Bi 2 O 3 /Vis/PMS system achieved the complete degradation of TC within 80 min, with a reaction rate constant of 0.0553 min −1 , which was 34.5 and 5.8 times higher than individual photocatalytic process and PMS-AOPs, respectively. This superior catalytic performance of Fe 2 O 3 /Bi 2 O 3 is primarily attributed to two key aspects. Firstly, forming a heterojunction promotes efficient segregation of photogenerated electron–hole pairs, wherein holes (h + ) directly activate PMS. Secondly, PMS simultaneously functioned as an electron acceptor to generate SO₄• − , accelerating the Fe 3+ /Fe 2+ redox cycle while inhibiting electron-hole recombination. This study confirmed the dual advantages of enhanced radical generation through PMS-assisted photocatalysis synergistic effects and improved charge separation via heterojunction engineering.