Liquid-phase exfoliation of titanium disulfide nanosheets in aqueous ionic liquid solutions for highly efficient CO2 electroreduction

Titanium disulfide nanosheets (TiS 2 NSs) have attracted considerable research interest due to their eco-friendliness and outstanding electrical transport properties. However, the large scale preparation of TiS 2 NSs usually is plagued by the employ of poisonous solvents and low production. Herein, we develop a green, highly efficient and scalable tactic to exfoliate bulk TiS 2 powders in aqueous ionic liquids solutions under ambient conditions. This result shows that the exfoliation yield can reach 57.6 %, which surpasses the most values for the liquid-phase exfoliation of TiS 2 reported in literatures. The thickness of TiS 2 NSs is mainly in the range of 1 nm to 2 nm, and the lateral dimension is up to a few hundreds of nanometers. The molecular geometry and anionic alkalinity of the ionic liquids play key roles in the delamination and stability of TiS 2 NSs. In addition, TiS 2 NSs have been used as catalysts in the electrocatalytic CO 2 to CO conversion with the faradaic efficiency of 68.7 %, which is six times that by the bulk TiS 2 powder. Thus, the liquid phase delamination approach reported in this work has a great potential in manufacturing 2D layer materials for high activity electrocatalysis.