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 Original Research Article

A catalyst comprising chains of dye-sensitized SnO2 nanocrystallites (10–15 nm) attached to larger ZnO (∼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 SnO2, to the conduction band of ZnO which is above that of SnO2. Wide charge separation suppresses recombinations, enabling separated charge to participate in chemical reactions.