Chemical Structure of TiO₂ Nanotube Photocatalysts Promoted by Copper and Iron

Table 1

Speciation data of the TNT, Cu-TNT, and Fe-TNT studied by EXAFS.

	Shells	Coordination number	Bond distance (Å)	Debye-Waller factor (𝜎^2 (Å^2))
TNT	Ti–O	4.2	1.87	0.01
	Ti–(O)–Ti	4.7	3.10	0.01
Cu-TNT	Ti–O	5.0	1.89	0.01
	Ti–(O)–Ti	4.1	3.14	0.01
	Cu–O	3.2	1.94	0.01
Fe-TNT	Ti–O	4.1	1.88	0.01
	Ti–(O)–Ti	6.7	3.15	0.01
	Fe–O	5.4	1.96	0.01