Bi2Sn2O7/BiOCl heterojunction photocatalysis for hydroxyl radical generation and inactivation of marine microorganisms

To address the issue of high electron–hole recombination rate in conventional catalysts used for the photocatalytic treatment of ballast water, this work designed and synthesized a Bi 2 Sn 2 O 7 /BiOCl heterojunction photocatalyst via a simple hydrothermal method. After 30 min of simulated sunlight irradiation, it exhibited outstanding inactivation efficiency against marine bacteria. The Bi 2 Sn 2 O 7 /BiOCl-0.6 heterojunction achieved an inactivation efficiency of up to 92%, 2.4 times higher than that of pure Bi 2 Sn 2 O 7 . Performance experiments and electrochemical analysis demonstrate that the heterojunction optimizes electron transfer pathways, enhances electron–hole separation efficiency, and promotes the generation of hydroxyl radicals, thereby significantly improving photocatalytic performance. This study offers novel insights for developing highly efficient photocatalytic ballast water treatment materials suitable for complex marine environments. Graphical abstract