Synergistic effects of monolayer Bi2MoO6 layered heterojunctions configuration and surface “Bi–O” vacancy defects of in enhanced photocatalytic antimicrobial performance

Developing efficient catalytic antimicrobial materials is crucial for mitigating air microbial pollution. In this study, a monolayer Bi₂MoO₆ with a unique [BiO]⁺–[MoO₄]²⁻–[BiO]⁺ interlayer substructure and “Bi–O” vacancy defects was synthesized through a simple exfoliation method using cetyltrimethylammonium bromide. These monolayers are chemically bonded to form a layered heterojunction. Under solar irradiation, holes are generated in the [BiO]⁺ layer, while electrons are produced in the [MoO₄]²⁻ layer, thereby facilitating efficient direct electron–hole separation. Additionally, the abundant “Bi–O” vacancy defects in the [BiO]⁺ layer result in crystal structure distortion, electron redistribution, and changes in the band gap energy of Bi₂MoO₆. The combination of layered heterostructures and vacancy defects significantly enhances solar light utilization and promotes photogenerated carrier separation, leading to excellent photocatalytic antimicrobial performance. Antibacterial tests reveal that after 20 min of irradiation, the monolayer Bi₂MoO₆ (0.20 mg/mL) deactivates 96.7 % of Escherichia coli and 74.5 % of Staphylococcus aureus. Notably, the antibacterial efficiency of the monolayer Bi₂MoO₆ is 1.9 and 2.7 times that of its multilayer counterpart for Escherichia coli and Staphylococcus aureus, respectively. This study provides novel insights and strategies for designing layered heterojunction Bi₂MoO₆ with enhanced photocatalytic antibacterial efficiency and tailored surface defects.