Fabrication mechanism of compact TiO₂ nanotubes and their photo-electrochemical ability

Ternary Ti–Mo–Fe Nanotubes as Efficient Photoanodes for Solar-Assisted Water Splitting

“…Besides, the E g bands originate essentially from the vibration of symmetric stretching from O–Ti–O in TiO 2 , and the B 1g mode originates from the vibration of symmetric bending from O–Ti–O in TiO 2 . Moreover, the A 1g band appeared as a result of the antisymmetric bending vibration from Ti–O–Ti, in agreement with the literature. , Furthermore, the strongest active mode at 141.87 cm –1 could be a reflection on the successful external symmetric vibration of Ti–Ti, confirming the anatase phase with long-range order, in agreement with the XRD results . Noticeably, the intensity of the peaks for the 8 h-31 sample was higher than that of 16 h-55 counterpart owing to the lower content of Ti in the latter.…”

“…The 16 h-55 sample showed the distinguished anatase peaks with some notable shifts in the bands compared to the 8 h-31 sample. This shift may be ascribed to the higher content of Mo and Fe in the 16 h-55 sample. , Moreover, the Raman peaks of the 8 h-31 sample exhibited a redshift when compared with several pure anatase TiO 2 reported in the literature. − Notably, this shift decreases as the concentration of Fe and Mo increases, which clearly appeared in the 16 h-55 sample, indicating a blueshift. Furthermore, introducing Fe and Mo into the TiO 2 crystal structure, as in the case of 8 h-31, the Ti–O bond length slightly increases along with increasing the crystal size; thus, the frequency of the interacting phonons was minimized.…”

“…The characteristic anatase bands of 8 h-31 and 16 h-55 samples were observed (Figure ). The peaks obtained at ∼141.87, 196.5, 391.64, 512.42, and 631.13 cm –1 could be assigned to the E g(1) , E g(2) , B 1g , A 1g , and E g(3) modes, respectively, confirming the existence of anatase phase (space group D 4 h 19 ). − Furthermore, the Raman active modes at 141.87 and 196.5 cm –1 correspond to the Ti–Ti metallic interaction, while the active vibrational modes ranging from 242 to 347 cm –1 can be ascribed to the O–O covalent interactions. Besides, the E g bands originate essentially from the vibration of symmetric stretching from O–Ti–O in TiO 2 , and the B 1g mode originates from the vibration of symmetric bending from O–Ti–O in TiO 2 .…”

“…59,64 Furthermore, the strongest active mode at 141.87 cm −1 could be a reflection on the successful external symmetric vibration of Ti−Ti, confirming the anatase phase with longrange order, in agreement with the XRD results. 59 Noticeably, the intensity of the peaks for the 8 h-31 sample was higher than that of 16 h-55 counterpart owing to the lower content of Ti in the latter. The 16 h-55 sample showed the distinguished anatase peaks with some notable shifts in the bands compared to the 8 h-31 sample.…”

Portable shifted excitation Raman difference spectroscopy for on‐site soil analysis

“…Raman signals from anatase located at 513 and 636 cm −1 are attributed to the antisymmetric bending vibration of Ti–O–Ti and the symmetric stretching vibration of O–Ti–O, respectively. [ 34 ] Moreover, the Raman signal at 513 cm −1 could also indicate the presence of feldspar with its additional contribution from the strong vibrational mode of the four‐membered ring of TO 4 tetrahedra. [ 35 ] The Raman signal indicated at 356 cm −1 corresponds to an additional A 1 mode of quartz.…”