Fig. 5. Theoretical atomic models for (a) anatase(112)-twin junction and (b and c) the anatase–rutile phase junction involving the intermediate phase of TiO2-II. The dihedral angle of the planes is denoted in the picture. For clarity, the Ti atoms in anatase, rutile and TiO2-II are represented by gray, blue and cyan, respectively. The inset in (a) shows the HRTEM patterns of anatase(112)-twin from ref. 44 and that in (c) from ref. 45. (d) A scheme showing the macroscopic structure evolution picture for anatase–rutile mixed oxide, containing anatase, rutile and TiO2-II. The concentration of TiO2-II is exaggerated to show clearly the spatial relation of the three phases.
