The photosensitized semiconductor catalysts - TiO2 nanotubes - were modified by functionalized supramolecular sensitizers: zinc(II)/copper(II)/cobalt(II) porphyrin-ruthenium(II) polypyridly complexes and photocatalytic activity of the modified TiO2 nanotubes were investigated through the reduction of CO2 aqueous solution as a probe reaction under UV-vis light. The diverse photoreduction properties of the catalysts resulted from the different polypyridly derivatives: 2,2'-bipyridyl, 1,10-phenanthroline, and 2,2'-bipyridyl-4,4'-dicarboxylate. The different central coordinated metal ions in the porphyrin ring influenced the photocatalytic efficiency of the sensitized-TiO2 system at the same time. A possible mechanism for the photocatalytic reduction was also proposed in this paper. (C) 2012 Elsevier B.V. All rights reserved.