The S-Scheme heterojunction design offers a promising pathway to enhance the photocatalytic activity of semiconductors for antibiotic degradation in aquatic environments. Graphitic carbon nitride (g-C₃N₄) stands out due to its robust visible light absorption, exceptional charge separation efficiency, and abundant active sites, rendering it an ideal candidate for sustainable and energy-efficient photocatalysis. This review delves into the potential of g-C₃N₄-based S-Scheme heterojunctions in antibiotic degradation, with a particular emphasis on the photocatalytic principles, inherent advantages, and application prospects. We discuss various semiconductor materials, including metal oxides, multicomponent metal oxides, magnetic oxides, multicomponent magnetic oxides, metal sulfides, and multicomponent metal sulfides, which can be paired with g-C₃N₄ to fabricate S-Scheme heterojunctions. Furthermore, we explore common preparation techniques for synthesizing g-C₃N₄-based S-Scheme heterojunction composites, such as the hydrothermal method, solvothermal method, calcination method, self-assembly method, in situ growth, etc. Additionally, we summarize the applications of these g-C₃N₄-based S-Scheme heterojunctions in the degradation of antibiotics, focusing specifically on quinolones and tetracyclines. By providing insights into the development of these heterojunctions, we actively contribute to the ongoing exploration of innovative technologies in the field of photocatalytic antibiotic degradation. Our findings underscore the vast potential of g-C₃N₄-based S-Scheme heterojunctions in addressing the challenge of antibiotic contamination in water sources.

Photodynamic therapy (PDT) holds considerable promise for advancing anticancer treatment, owing to its precision and minimally invasive nature. In this study, we successfully synthesized a series of titanium carbide (Ti₃C₂, TC)/graphitic carbon nitride (g-C₃N₄, CN) nanocomposite through a synergistic approach combining electron beam irradiation and 2D/2D composite formation. According to the results, 1TC/200-CN (1TC, which TC was 1, referred to the mass ratio; 200-CN, which CN was 200 kGy, referred to the irradiation metering) displayed a 94% degradation rate of methylene blue (10 mg/L) in 100 min. Furthermore, the proliferation rate of CAL-27 cells was suppressed to just 23.3% at a concentration of 320 μg/mL of 1TC/200-CN. Notably, the group treated with this concentration exhibited the largest residual scratch area, accompanied by a notable decrease in mitochondrial membrane potential. These enhanced effects were attributed to the efficient transfer of electron-hole pairs facilitated by the TC/CN composite. Our findings not only contribute to the development of efficient and stable nanocomposites for PDT applications but also provide valuable insights into the utilization of nanomaterials in the biomedical field, thereby paving the way for potential breakthroughs in cancer treatment.

Photodynamic antibacterial therapy presents a promising strategy for combating bacterial infections due to its non-invasive nature and low potential for inducing resistance. In this work, we developed a series of electron beam-modified graphitic carbon nitride (g-C₃N₄, CN) and titanium carbide (Ti₃C₂, TC) nanocomposites, which were subsequently incorporated into polyvinyl alcohol/sodium alginate (PVA/SA) hydrogels through physical cross-linking. The optimized 200CN/1TC composite hydrogel (where 200CN denotes 200 kGy irradiation dose, and 1TC represents 1 wt% TC content) maintained excellent biocompatibility with cell viability exceeding 80% even at the highest nanomaterial loading (8% 200CN/1TC). Notably, the 8% 200CN/1TC composite hydrogel displayed substantial antibacterial activity, forming inhibition zones of 12.3 mm and 10.8 mm against Staphylococcus aureus and Escherichia coli, respectively. The improved performance may be explained by the combined effects of enhanced electron transfer between the component materials and the unique two-dimensional structure of the nanocomposites, though further investigation is required to fully elucidate the underlying mechanisms. This study provides a feasible approach for developing efficient antibacterial hydrogel systems and offers valuable perspectives on the design of nanomaterial-based biomedical materials for wound healing and infection control applications.