Atomic Zn–N₄ Site-Regulated Donor–Acceptor Catalyst for Boosting Photocatalytic Bactericidal Activity

Reactive oxygen species (ROS)-mediated photocatalytic antibacterial materials are emerging as promising alternatives for the antibiotic-free therapy of drug-resistant bacterial infections. However, the overall efficiency of photocatalytic sterilization is restricted by the rapid recombination of the charge carriers. Herein, we design an in-plane π-conjugated donor-acceptor (D-A) system (g-C₃N₄-Zn-NC), comprising graphitic carbon nitride (g-C₃N₄) as the donor and Zn single-atom anchored nitrogen-doped carbon (Zn-NC) as the acceptor. Experimental and theoretical results reveal that the introduction of Zn-NC induces the formation of an intermediate band in g-C₃N₄-Zn-NC, extending the spectral absorption range and facilitating charge carrier transfer and separation. Additionally, the synergistic effects of the dual sites, the N═C-N sites of the g-C₃N₄ "donor" and the atomic Zn-N₄ sites of the Zn-NC "acceptor", boost ROS production. Consequently, the biocompatible g-C₃N₄-Zn-NC effectively kills methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) under visible-light irradiation and promotes the healing of MRSA-infected wounds on mouse skin.