Anodic Fabrication of Highly Ordered ${\rm TiO}_{2}$ Nanotube Arrays and Its Hydrogen Sensing

In this paper, highly ordered
${\rm TiO}_{2}$
nanotube arrays are fabricated via electrochemical anodization of high purity Ti foil in fluorine containing electrolytes. The field emission scanning electron microscopy measurements show that the morphology of
${\rm TiO}_{2}$
nanotube arrays is affected by the two-step anodization process and the polar solvent containing electrolytes. With two-step anodization, the surface morphology of
${\rm TiO}_{2}$
nanotube arrays is orderly and uniform. Moreover, the pore diameter is stupendously homogeneous. The structural parameters of
${\rm TiO}_{2}$
nanotube arrays were improved by the addition of polar solvent, water, to electrolytes. After annealing treatment and Pd nanoparticle doping, the hydrogen sensing characteristics of
${\rm TiO}_{2}$
nanotube arrays were analyzed by measuring its electric resistance response in different
${\rm H}_{2}$
concentrations. The results demonstrate that
${\rm TiO}_{2}$
nanotube arrays have high hydrogen sensitivity at room temperature.