Surfactant-assisted shape evolution of thermally synthesized TiO ₂ nanocrystals and their applications to efficient photoelectrodes

TiO₂ nanocrystals were synthesized via a two-phase thermal process, and the shape of the nanocrystals was controlled from nanospheres to nanorods by the ratio of two surfactants. The shape control of nanocrystals was ascribed to the selective adsorption of the two surfactants. The shape of TiO₂ nanocrystals influenced the photocatalytic performances of the photoelectrodes through two compromising factors: the relative surface area and the electron transport. The photoelectrode composed of nanorods showed a slower charge recombination rate, while it showed a smaller specific surface area, compared to nanospheres. As a result, the photoelectrodes showed the optimal photocatalytic performance when the nanospheres and the nanorods were mixed.