Abstract:
The effect of water content in the electrolyte solution during annealing process in the synthesis and
modification of titania nanotube arrays (TNTAs) by anodic oxidation process has been investigated.
Variations in annealing technique that leading to some specific properties of the TNTAs produced have
been examined. Doped-TNTAs were obtained by the in-situ anodic oxidation method in glycerol containing fluoride solution followed by annealing to induce crystallization. FESEM and SEM results indicated that TNTAs with inner diameters of 49e80 nm, wall thicknesses from 28 to 42 nm and lengths from
1407 to 1570 nm were synthesized. At water content of 25 v% in the electrolyte solution, self-organized
with vertical, ordered of TNTAs with relatively uniform diameter was observed. Suitable morphology of
TNTAs such as well developed tubes, vertically oriented, highly ordered, long with optimal diameter and
wall thickness of TNTAs could suppress recombination of electronseholes and, therefore, increase
photoelectrochemical properties. Annealing with H2/Ar is found to be efficient for introducing dopant C
and N into the lattice of TNTAs to form TieOeC and NeTieO (FTIR analysis). Therefore, the reducing band
gap can be obtained (UVeVis DRS analysis). Annealing under H2/Ar of as-synt TNTAs with water content
of 25 v% in the electrolyte solution produced anatase phase (XRD analysis) and showed optimal condition
in producing the highest photocurrent density
