Photocatalytic activity of dye-sensitized tin(IV) oxide nanocrystalline particles attached to zinc oxide particles: long distance electron transfer via ballistic transport of electrons across nanocrystallites

A catalyst comprising chains of dye-sensitized SnO(2) nanocrystallites ( 10-15 nm) attached to larger ZnO (similar to 600 nm) particles is found to photogenerate hydrogen from water with visible light in the presence of a hole scavenger. The catalytic activity originates from ballistic injection of energetic electrons generated in sensitization of SnO(2), to the conduction band of ZnO which is above that of SnO(2). Wide charge separation suppresses recombinations, enabling separated charge to participate in chemical reactions. (C) 2001 Elsevier Science B.V. All rights reserved.