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

• A TiO2–TiC shell–core S-scheme photocatalyst was synthesized via thermal treatment of TiC in carbon powder, forming a TiO2 shell with oxygen vacancies around TiC nanoparticles. • The optimized shell–core structure (cHT500) exhibits strong visible-light absorption (400–800 nm) and a RhB degradation rate constant of 0.0687 min⁻¹, 20.8 times higher than pristine TiO2 under visible light. • Cytocompatibility assays show cHT500 has favorable cell viability comparable to TiO2 NPs, overcoming the poor biocompatibility of TiC for biomedical use. • The work provides a strategy to engineer TiO2-based photocatalysts with enhanced visible light response and biocompatibility for photocatalytic and biomedical applications.