fig15
![Solid-state NMR of active sites in TiO<sub>2</sub> photocatalysis: a critical review](https://image.oaes.cc/aee4ec06-4c22-4959-90f1-d08b90ca3a45/cs4012.fig.15.jpg)
Figure 15. (A) 15N MAS NMR spectra of 15N-doped TiO2 prepared by sol-gel methods; (B) 15N MAS NMR spectra of 15N-doped TiO2 monolayer and powders by direct nitridation. Reproduced with permission from[200]. Copyright 2007, American Chemical Society. MAS: Magic angle spinning; NMR: nuclear magnetic resonance.