Synthesis of TiO2 nanosheet photocatalysts from exfoliation of TiS2 and hydrothermal treatment

TiO 2 nanomaterials with platelet or nanosheet morphologies can offer improved properties for photocatalytic applications, but established methods to produce them typically require structure-directing agents since anatase-phase TiO 2 does not have a layered structure. In the present work, the preparation of TiO 2 nanosheets by the chemical oxidation of TiS 2 nanosheets is demonstrated. Electrochemical exfoliation of bulk TiS 2 into TiS 2 nanosheets, followed by the hydrothermal treatment at 180 °C for 14 h is performed. The results show that polycrystalline TiO 2 nanosheets with the anatase structure are formed, and that the nanosheet morphology can still be maintained after the hydrothermal treatment. The TiO 2 nanosheets show good photocatalytic activity for the degradation of methylene blue, but the performance is negatively affected by the residual carbon black that was needed in the TiS 2 electrode to enable electrochemical exfoliation. These results show that conversion of TiS 2 nanosheets to TiO 2 nanosheets is a promising synthetic strategy but highlights how the interfacial properties of the obtained materials could be affected by ancillary components in the preparation method.