文档介绍：Craig A. Grimes l Gopal K. Mor
TiO2 Nanotube Arrays
Synthesis, Properties, and Applications
Photoelectrolysis Using Anionic and Cationic Doped TiO2 Nanotubes 173
array structure. The photocurrent action spectra recorded at 2 V Ag/AgCl for an
NH3-treated (at 600C) sample in M Na2SO4 showed significantly higher
photocurrents in the visible range than the undoped samples. It was evident that
N-doping also enhanced the UV light photoresponse.
For making N, B, or F doped TiO2 nanotubes [94–96], Su et al. first anodized Ti
foil at 20 V for 1 h in M C2H2O42H2O containing wt% NH4F, dried in a
stream of dry nitrogen at 300C for 30 min. The sample was then annealed, 400C
or 600C, while exposed to a compositional gas stream, nitrogen passing a ( wt%
NaF wt% H3BO3 solution heated at 80C) at a rate of 3,300 mL/min. To make
fluorineþ doped samples, a precursor solution containing wt% NaF was used; for
B-doped sample, a wt% H3BO3 solution was used as the precursor. Experiments
were carried out under visible light irradiation (300 W Xe lamp) using a UV filter
[97, 98] in M Na2SO4 electrolyte. N-F doped TiO2 nanotubes made at 600C
showed modestly improved photocurrents. Chen et al. reported fabrication of P-F
doped TiO2 nanotubes by anodizing the Ti foil in M H3PO4 containing a small
amount of HF ( wt%) [99].
Beranek and co-workers reported nitrogen and carbon surface-modified
TiO2 nanotubes by heating TiO2 in a gaseous atmosphere of urea pyrolysis
products at 400C[100]. The TiO2 nanotube array samples were made using
1MH2SO4 M HF, glycerol/water (50:50 vol%) M NH4F, glycerol
M NHþ F, and EG M NH F electrolytesþ and then annealed at
þ 4 þ 4
450C for 3 h in air. For surface modification [101, 102], the electrodes were
placed into a 170 mL Schlenk tube connected via an adapter with a 70 mL
round bottom flask containing 1 g of urea and hea