Three-Dimensional CdS-Sensitized Sea Urchin Like TiO2-Ordered Arrays as Efficient Photoelectrochemical Anodes

We demonstrate the fabrication of a 3D ordered sea urchin like TiO 2 structure by combining colloidal spheres template, atomic layer deposition (ALD), and hydrothermal growth method. The 3D sea urchin like TiO 2 arrays as photoanode present improved photoelectrochemical performance in contrast to 2D TiO 2 hollow microspheres and 1D TiO 2 nanowires arrays. With CdS quantum dots sensitization, the sea urchin like TiO 2 array photoanode yields a photocurrent of 5.4 mA cm –2 at 0 V vs Ag/AgCl. The performance improvement is attributed to the increased specific surface area and porosity, light trapping effect by multiscattering of the hierarchical structure, as well as direct charge transportation paths from the nanorods to the microspheres.