New mesostructured porous TiO2 surface prepared using a two-dimensional array-based template of silica particles

Mesoporous photocatalytic titanium dioxide films with periodic structures were prepared by molding from two-dimensionally ordered arrays of monodisperse SiO2 particles. The morphology of the porous structures in these films was dependent upon the annealing temperature. The photocatalytic activity of the films was confirmed, as evidenced by the photodeposition of silver on the textured film surfaces. Attachment of the free-standing films to rigid supports allowed us to locate specific microscopic areas at will and to monitor the progress of the silver photodeposition in these areas using optical. microscopy and scanning electron microscopy, with both secondary electron and backscattered electron detection. However, the repeated electron beam exposure in these selected areas was found to adversely affect the photoreducibility. Although the detailed film morphology did not affect the macroscopic photocatalytic activity, we found subtle differences in the silver nucleation process which depended upon the pore wall thickness.