|
| Technique | Characterization | Evidence | References |
|
| Colour of the materials | Different from pristine TiO2 | The defects maybe exist | [123] |
| High-resolution transmission electron microscopy (HR-TEM) | The atomic lattice is blurred | Maybe exists | [72, 123] |
| Ultraviolet-visible spectroscopy (UV-vis) | An optical absorption band above 400 nm | Maybe exists | [30] |
| Photoemission spectroscopy (PL) | The emission position and intensity | Type, relative concentration of defects | [124] |
| Raman spectroscopy | Variation in vibration of O and Ti-related region | Type of defects | [30, 38, 72] |
| X-ray photoelectron spectroscopy (XPS) | Valence state variation | Type of defects mainly Ti3+ | [30, 37, 72, 89] |
| Electron paramagnetic resonance (EPR) | factor calculated from the position of the sharp signal | Type of paramagnetic defects | [35, 123, 125, 126] |
| Positron annihilation lifetime spectroscopy (PALS) | The lifetime of the positrons | Size, type, and relative concentration of defects | [68] |
| Scanning tunneling microscopy (STM) | Light dot in pictures | The type, position of defects | [31, 113, 120] |
| Atomic force microscopy (AFM) | Comparison of pictures | The type, position of defects | [38] |
| Temperature programmed deoxidation (TPD) | A narrow peak related to partial oxygen loss according to temperature. | Rough concentration of oxygen defects | [112, 123, 125] |
| Electron energy loss spectroscopy (EELS) | Energy loss | Electronic change in defects | [112] |
| Synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS) | Peak position | Geometrical structure of active sites | [127] |
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