Coverage Layer Phase Composition-Dependent Photoactivity of One-Dimensional TiO(2)–Bi(2)O(3) Composites

TiO(2)–Bi(2)O(3) composite rods were synthesized by combining hydrothermal growth of rutile TiO(2) rod templates and sputtering deposition of Bi(2)O(3) thin films. The TiO(2)–Bi(2)O(3) composite rods with β-Bi(2)O(3) phase and α/β-Bi(2)O(3) dual-phase decoration layers were designed, respectively, via in situ radio-frequency magnetron sputtering growth and post-annealing procedures in ambient air. The crystal structure, surface morphology, and photo-absorption performances of the pristine TiO(2) rods decorated with various Bi(2)O(3) phases were investigated. The crystal structure analysis reveals that the crystalline TiO(2)–Bi(2)O(3) rods contained β-Bi(2)O(3) and α/β-Bi(2)O(3) crystallites were separately formed on the TiO(2) rod templates with different synthesis approaches. The morphology analysis demonstrates that the β-Bi(2)O(3) coverage layer on the crystalline rutile TiO(2) rods showed flat layer morphology; however, the surface morphology of the α/β-Bi(2)O(3) dual-phase coverage layer on the TiO(2) rods exhibited a sheet-like feature. The results of photocatalytic decomposition towards methyl orange dyes show that the substantially improved photoactivity of the rutile TiO(2) rods was achieved by decorating a thin sheet-like α/β-Bi(2)O(3) coverage layer. The effectively photoinduced charge separation efficiency in the stepped energy band configuration in the composite rods made from the TiO(2) and α/β-Bi(2)O(3) explained their markedly improved photoactivity. The TiO(2)-α/β-Bi(2)O(3) composite rods are promising for use as photocatalysts and photoelectrodes.