Enhanced visible light response and cytocompatibility of TiO2-TiC shell-core structured S-scheme photocatalyst

To enhance the visible light response of titanium dioxide (TiO₂), titanium carbide (TiC) nanoparticles (NPs) were thermally treated in carbon powder, effectively overcoming the challenges associated with conventional doping methods. During the treatment, a TiO₂ thin shell with oxygen vacancies (OVs) formed around the TiC NPs, creating a shell-core structure S-scheme photocatalyst. Transmission electron microscopy (TEM) and Ultraviolet-visible (UV-vis) spectroscopy confirmed the successful formation of the TiO₂ shell. By optimizing the shell thickness, the TiO2-TiC shell-core structure achieved an ideal shell-core ratio (cHT450), resulting in strong visible light absorption (400-800 nm) and a Rhodamine B (RhB) degradation rate of 0.107 mg/(min·L), which is 2.7 times higher than that of TiO₂ under visible light. In addition, cytocompatibility tests showed that TiC NPs treated at 500 °C for 1 h exhibited improved cell survival, comparable to TiO₂ NPs. The TiO₂-TiC shell-core NPs demonstrated enhanced photocatalytic efficiency under visible light and good cytocompatibility, making them promising candidates for biomedical and photocatalytic applications.