N,S co‐doped TiO₂ nanoparticles and nanosheets in simulated solar light for photocatalytic degradation of non‐steroidal anti‐inflammatory drugs in water: a comparative study

Background In this study, highly visible‐light photoactive nitrogen and sulfur co‐doped TiO 2 (N,S‐ TiO 2 ) nanoparticles and nanosheets were synthesized via facile sol–gel and hydrothermal methods, respectively. The photocatalytic activities of N,S‐ TiO 2 catalysts were evaluated by degradation of non‐steroidal anti‐inflammatory drugs, ibuprofen ( IBP ) and naproxen ( NPX ), under simulated solar irradiation. Results The N,S‐ TiO 2 nanoparticle is a well‐developed mesoporous structure that contains both anatase and rutile phases and a large BET surface area (132 m 2 g −1 ). N,S‐ TiO 2 nanosheets contain a complete anatase phase with a larger mesoporous structure and a smaller BET surface area (64 m 2 g −1 ). The results showed that at catalyst loading of 2.0 g L −1 and pH 6, N,S‐ TiO 2 nanoparticles can degrade 85% and 99.3% of IBP and NPX . At the same conditions, 71.6% of IBP and 99.1% of NPX were degraded by N,S‐ TiO 2 nanosheets in this study. Conclusion The high photocatalytic activity of N,S‐ TiO 2 may be due to synergistic effects of nitrogen and sulfur co‐doping into TiO 2 , resulting in better separation of photogenerated electrons and holes and higher‐visible light adsorption. Reusability tests of N,S‐ TiO 2 showed that it could retain its catalytic activity even after six cycles.