Visible light photocatalysis by a titania transition metal complex

Chemisorption of H2[PtCl6] onto high surface anatase powder leads to formation of the surface complex {[Ti]OPtCl4L}n-, L=H2O, OH-, n=1, 2, in which titania acts as a ligand. Depending on the coverage, the chloroplatinate group induces an anodic shift of the band edges by up to 260 mV, thus changing the photoredox properties of the semiconductor substantially. Efficient charge separation upon visible light excitation most likely occurs through initial PtCl bond homolysis followed by fast electron injection into the titania conduction band. The resulting spatial separation of the charges should disfavor recombination. This novel semiconducting surface metal complex is an excellent photocatalyst for the mineralization of various pollutants by artificial visible and even natural indoor daylight. © 2004 Elsevier Inc. All rights reserved.