Lysozyme-assisted ultrasonic exfoliation of graphitic carbon nitride into highly stable nanosheets with enhanced bactericidal capacity

Graphitic carbon nitride (g-C3N4) is a visible light-responsive photocatalytic material with important application prospects in many fields. However, the interaction between g-C3N4 monolayers makes it easy to aggregate and precipitate in aqueous solutions, and it is necessary to prepare stable g-C3N4 aqueous dispersions for their applications. Here we propose a facile, green, and low-cost method for the preparation of stable g-C3N4 dispersions by ultrasonicating g-C3N4 in lysozyme (LYZ) solution. The LYZ was adsorbed on the surface of g-C3N4 through non-covalent interactions such as electrostatic interaction, hydrogen bonding and π-cation interaction to prevent the aggregation of g-C3N4 nanolayers. The LYZ/g-C3N4 could quickly re-form a uniform aqueous dispersion solution after freeze-drying, and exhibit good stability. Further, the results of photocatalytic sterilization showed that the assisted dispersion of LYZ enhanced the bactericidal activity of g-C3N4 and exhibited promising application prospects in the field of biomedicine and water disinfection.