Antibacterial Performance of Copper-loaded Mesoporous C₃N₆

Copper-loaded mesoporous nitrogen-rich carbon nitride (xCu-mC₃N₆) was synthesized using a mesoporous silica SBA-15 hard template. While low-angle XRD data and transmission electron microscopic images confirm the periodic hexagonal porous texture of the synthesized material, the nitrogen adsorption-desorption isotherms revealed high specific surface areas with an average pore diameter of ∼4.9 nm. CHN analysis established the formation of C₃N_6, and near-edge X-ray absorption Fine Structure (NEXAFS) measurements confirmed N─C═N in the C₃N₆ framework. The copper-based nanoparticles are anchored onto the CN framework within the mesochannels of C₃N₆. The inhibition zones revealed that Cu-mC₃N₆ exhibited a stronger antibacterial effect compared to mC₃N_6, and interestingly. Gram-positive Bacillus subtilis (B. subtilis) performs better than gram-negative Escherichia coli (E. coli) bacteria. Further, the colony-counting method quantitatively confirmed the superior antibacterial performance of xCu-mC₃N₆, compared to mC₃N₆. Cu-mC₃N₆ also achieved an 87% increase in intracellular reactive oxygen species (ROS) production in B. subtilis and 71% for E. coli-treated cells, implying ROS-mediated cell death in Cu-mC₃N₆, while mC₃N₆ exhibited a lower level of ROS owing to weak electrostatic interactions with bacteria, resulting in lower antibacterial effects. The present study provides insight into the synthesis of nitrogen-rich nanocomposites for disinfection.