Visible-Light Photodegradation of Dye on Co-Doped Titania Nanotubes Prepared by Hydrothermal Synthesis

Table 1

Surface characteristics of Co-TiO₂ nanotubes determined from N₂ physisorption at −196°C.

Materials	𝐶^aCo	𝑆^bBET	𝑉t^c	Pore size distribution
type	(ions/cm^3)	(m^2/g)	(cm^3/g)	𝑉^dmicro (%)	𝑉^emeso (%)
P25	—	45.8	0.121	0.016 (16)	0.102 (84)
TNT	0	376	0.929	0.118 (13)	0.811 (87)
Co-1-TNT	1.90×10^20	379	0.934	0.117 (13)	0.816 (87)
Co-3-TNT	4.31×10^20	350	0.975	0.118 (12)	0.857 (88)
Co-5-TNT	5.59×10^20	341	0.932	0.117 (12)	0.815 (88)
Co-7-TNT	7.31×10^20	289	0.685	0.118 (17)	0.567 (83)

^a𝐶_Co: cobalt atomic concentration determined from EDS analysis.
^b𝑆_BET: specific surface area computed using BET equation.
^c𝑉_𝑡: total pore volume estimated at a relative pressure of 0.98.
^d𝑉_micro: micropore volume determined from DR equation.
^e𝑉_meso: mesopore volume determined from the subtraction of micropore volume from total pore volume.