Enhanced Generation of Hydroxyl Radicals on a Facet Engineering Bi2Fe4O9 Photocatalyst for Efficient Fungal Inactivation

The fungicidal efficacy of hydroxyl radicals (•OH) on fungal biosynthetic pathways and metabolic processes has been well-documented, but the precise modulation of •OH generation remains a significant challenge. Herein, we engineered a dual-cocatalyst-modified Bi₂Fe₄O₉ (BFO) system by loading Au nanoparticles on (010) facets and MnO_x nanosheets on (100) facets. Au/MnO_x/BFO demonstrates a 4.2-fold enhancement in antifungal activity compared to pristine BFO. Field application studies reveal that complete prevention of Curvularia lunata infection was achieved when Au/MnO_x/BFO was sprayed on the corn leaves. Spectroscopic analyses elucidate that the MnO_x nanosheets facilitate efficient hole transport, while Au nanoparticles enhance electron transfer and subsequent •OH generation onto the MnO_x surface. RNA sequencing reveals that Au/MnO_x/BFO induces fungal inactivation by disrupting critical metabolic pathways, ultimately leading to fungal cell death. These findings demonstrate the potential of facet engineering on semiconductor photocatalysts against fungal pathogens in plant protection for the development of sustainable agriculture.