Unusual synthesis of safflower-shaped TiO2/Ti3C2 heterostructures initiated from two-dimensional Ti3C2 MXene

Unusual synthesis of microscale safflowers consisting of TiO2/Ti3C2 heterostructure nanorods was developed. This unique structure was realized by the sequential in-body transformation, starting from two-dimensional Ti3C2Tx MXene. For the transformation, hydrothermal oxidation and alkalization, ion exchange, and heat treatment were elaborately combined in a stepwise manner. Undergoing those steps, the layer-structured MXene flakes were broken into nanoparticles, and TiO2/Ti3C2 nanorods grew radially from the nanoparticles. It was revealed that the heat treatment conditions had a significant effect on the morphology, structural components, and properties of the heterostructures. Unlike Ti3C2Tx MXene, the TiO2/Ti3C2 heterostructures synthesized at optimal conditions behaved like a semiconductor. The superb photocatalytic efficiency of the heterostructures was also demonstrated.