Toward next-generation antimicrobial technologies: g-C₃N₄ photocatalysts for sustainable disinfection under visible light

The rapid rise of antimicrobial resistance (AMR) and increasing microbial contamination in water, air, and surface environments call for sustainable and effective disinfection strategies beyond traditional chemical treatments. Visible-light-driven photocatalysis has emerged as a green alternative; however, most traditional photocatalysts suffer from drawbacks such as high cost, instability, and limited visible-light utilization. Among the various photocatalysts examined, graphitic carbon nitride (g-C 3 N 4 ) has attracted considerable attention as a next-generation disinfection material due to its metal-free structure, tunable electronic structure, low-cost synthesis, and strong stability under visible light. This review uniquely consolidates recent advances in g-C 3 N 4 -based antimicrobial photocatalysts by highlighting how structural modifications such as elemental doping, vacancy engineering, morphology tailoring, and heterojunction formation address these intrinsic limitations. Unlike previous reports, these emphasize the mechanistic pathways of microbial inactivation, linking charge transfer processes with oxidative stress, membrane rupture, and genetic material degradation. Furthermore, the critical assessment of the translation of these laboratory-scale findings into photocatalytic applications in water purification, surface sterilization, and air treatment outlines performance benchmarks and environmental safety concerns. Key challenges, including charge carrier recombination, limited light absorption, and environmental durability, are addressed alongside emerging solutions. By identifying unresolved knowledge gaps and emerging design principles, this work provides new insights into the rational engineering development of g-C 3 N 4 -based photocatalysts and their practical distribution in scalable antimicrobial technologies. GRAPHICAL ABSTRACT Visible-light-driven g-C 3 N 4 photocatalysts generate reactive oxygen species (ROS) that disrupt microbial cells through oxidative stress, offering a sustainable and metal-free approach for water, air, and surface disinfection.