fig18

Figure 18. (A) 1D ²⁷Al MAS NMR spectra of TiO_2-xF_x(001) and Al–TiO_2-xF_x(001) catalysts; (B) 2D ²⁷Al 3Q MAS NMR spectrum of the Al–TiO_2-xF_x(001) sample; (C) 1D ¹⁹F MAS NMR spectra of various of TiO_2-xF_x(001) and Al–TiO_2-xF_x(001) catalysts; (D) 2D ¹⁹F–²⁷Al D-HMQC spectrum of the Al–TiO_2-xF_x(001) catalyst. Reproduced with permission from^[225]. Copyright 2022, American Chemical Society. 1D: One-dimensional; MAS: magic angle spinning; NMR: nuclear magnetic resonance; 2D: two-dimensional; D-HMQC: dipolar heteronuclear multiple-quantum coherence.