Nanostructured TiO2 (ns-TiO2) films obtained by supersonic cluster beam deposition possess highly porous, defective structures, and allow efficient incorporation of carbon-containing molecules during thermal treatment. Carbothermal reduction modifies the electronic structure of the ns-TiO2, narrowing the optical gap to 2 eV. This is within the range of visible solar radiation (see Figure), allowing more efficient photoconversion.