Molecular assembly of carbon nitride-based composite membranes for photocatalytic sterilization and wound healing.

Polymeric carbon nitride (pCN) has attracted increasing interest as a metal-free photocatalyst because of its high efficiency in reactive oxygen species (ROS) generation. However, due to poor solubility, compounding pCN at the molecular level into more advanced nanocomposites remains a challenge. Herein, we report the dissolution of pCN in polyphosphoric acid (PPA) for the first time and fluid-phase assembly with carbon nanotubes (CNTs) into a flexible free-standing membrane. Mechanism and generality studies disclosed that the coordination of the acidity, viscosity, and adsorption energy of the solvents led to the successful dissolution of pCN. Interestingly, the pCN/CNTs molecular composite membrane exhibited not only superior mechanical properties and cycling performance as a result of strengthened π-π interfacial interaction, but also outstanding inactivation of E. coli and S. aureus in sterilization and wound healing for laboratory mice via photogenerated oxygen radicals. It would open a new era of pCN for biomedical applications in molecular composite membranes, beyond the traditional solar fuel applications in powders.