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 TiO2 (N,S‐TiO2) nanoparticles and nanosheets were synthesized via facile sol–gel and hydrothermal methods, respectively. The photocatalytic activities of N,S‐TiO2 catalysts were evaluated by degradation of non‐steroidal anti‐inflammatory drugs, ibuprofen (IBP) and naproxen (NPX), under simulated solar irradiation. Results The N,S‐TiO2 nanoparticle is a well‐developed mesoporous structure that contains both anatase and rutile phases and a large BET surface area (132 m2 g−1). N,S‐TiO2 nanosheets contain a complete anatase phase with a larger mesoporous structure and a smaller BET surface area (64 m2 g−1). The results showed that at catalyst loading of 2.0 g L−1 and pH 6, N,S‐TiO2 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‐TiO2 nanosheets in this study. Conclusion The high photocatalytic activity of N,S‐TiO2 may be due to synergistic effects of nitrogen and sulfur co‐doping into TiO2, resulting in better separation of photogenerated electrons and holes and higher‐visible light adsorption. Reusability tests of N,S‐TiO2 showed that it could retain its catalytic activity even after six cycles. © 2015 Society of Chemical Industry