Sulfur-induced electronic coupling in g-C3N4/Ti3C2Tx-MXene 2D/2D heterojunction enables highly efficient solar-driven disinfection

Two-dimensional (2D/2D) heterojunction photocatalysts hold great promise for solar-driven antibacterial disinfection owing to their unique interfacial architectures and tunable electronic properties. However, insufficient interfacial electronic coupling and ineffective charge separation still hinder their practical performance. Here, a sulfur-doped g-C 3 N 4 /Ti 3 C 2 Tx-MXene (SCN/MXene) 2D/2D heterojunction is rationally designed to enable efficient charge separation and transfer, delivering superior solar-driven antibacterial activity with remarkable stability. Combined experimental and theoretical analyses reveal that sulfur doping modulates the electronic structure of g-C 3 N 4 , elevates its Fermi level, and strengthens interfacial electronic coupling with Ti 3 C 2 Tx-MXene, thereby enhancing the built-in electric field and facilitating charge transfer across the interface. Moreover, S-doping induces interfacial charge redistribution, enhancing O 2 adsorption and activation at Ti sites and thereby accelerating the generation of reactive oxygen species (ROS). Consequently, SCN/MXene achieves nearly complete inactivation of Escherichia coli , Staphylococcus aureus , and methicillin-resistant Staphylococcus aureus within 60 min under solar irradiation, outperforming most of the state-of-the-art photocatalysts.