Thermal stability of two-dimensional Ti2C nanosheets

Two-dimensional Ti2C nanosheets were prepared by exfoliation of Ti2AlC powders in HF solution at room temperature. The thermal stability and structural changes during heating of the as-prepared Ti2C nanosheets were studied. The graphene-like layered structure of the as-prepared Ti2C nanosheets was confirmed by SEM, TEM and XRD. Crystal defects were discovered in the as-prepared Ti2C nanosheets. TG–DSC analysis and EDX results suggest that the surface group OH and F could be eliminated by heat treatment. When heated to 500 K, anatase TiO2 forms in the Ti2C nanosheets, which then transforms to rutile TiO2 at higher temperature. Twinning transformation induced by heat treatment is found in the as-prepared Ti2C nanosheets, which can be attributed to the existence of stacking faults.