Abstract
In this study, TiO 2 /SnO 2 -Pd heterostructures with enhan-ced photocatalytic activity were synthesized by the sensitization and activation of TiO 2 nanotubes with SnO 2 -Pd nanoparticles. The growth of the SnO 2 -Pd nanoparticles was dominated by the crystal structures of the TiO 2 nanotubes and the sensitization time. On 450 °C annealed anatase TiO 2 nanotubes, grown SnO 2 -Pd nanoparticles were uniformly stacked in a layer with specific structural orientations of Pd(111)-anatase TiO 2 (200) and SnO 2 (110)- anatase TiO 2 (101). In contrast, on as-anodized amorphous TiO 2 nanotubes, SnO 2 -Pd nanoparticles were randomly packed. The deposited rutile SnO 2 nanoparticles induced the crystallization of amorphous TiO 2 into a rutile phase with specific lattice correlations of Pd(111)-rutile TiO 2 (101) and SnO 2 (110)- rutile TiO 2 (110) during late-stage annealing at 450 °C. The rutile TiO 2 -SnO 2 -Pd heterostructures had a lower photocatalytic efficiency in the degradation of methylene blue than did the anatase heterostructures but had a higher efficiency than the bare TiO 2 nanotubes. © 2011 American Chemical Society.