The behaviors of anatase and TiO2(B) phase coexisting nanosheets under high pressure

• High pressure behaviors of TiO2 and TiO2(B) coexisting nanosheets were investigated.
• The anatase phase existed and TiO2(B) phase almost cannot be observed upon compression.
• The unique high pressure behaviors were discussed.
• The coexistence nanosheet has high incompressibility.

High pressure behaviors of anatase TiO2 and TiO2(B) coexisting nanosheets were investigated using in situ synchrotron X-ray diffraction and Raman Spectroscopy. The X-ray diffraction revealed that upon compression an α-PbO2 phase appeared at 11.4 GPa, and then the baddeleyite phase appeared at 23.6 GPa. Upon decompression the anatase phase still existed obviously and TiO2(B) phase almost cannot be observed. The Raman spectrum at ambient pressure presented the typical curve of anatase TiO2, however the pressure dependence for compression and decompression did not show the common phase transion from anatase to α-PbO2 or to baddeleyite. This is different from high pressure behaviors of other TiO2 nanostructures and could be attributed to the existence of small amount of TiO2(B) at the starting materials. The pressure relationship of the Raman frequencies shift slope indicated the coexistence nanosheet has high incompressibility compared with other TiO2 nanomaterials and corresponding bulks.