  The synthesis of nanocomposite materials combining titanate nanofibers (TNF)
with nanocrystalline ZnS and Bi2S3 semiconductors is described in this work.
The TNF were produced via hydrothermal synthesis and sensitized with the
semiconductor nanoparticles, through a single-source precursor decomposition
method. ZnS and Bi2S3 nanoparticles were successfully grown onto the TNF's
surface and Bi2S3-ZnS/TNF nanocomposite materials with different layouts were
obtained using either a layer-by-layer or a co-sensitization approach. The
samples' photocatalytic performance was first evaluated through the production
of the hydroxyl radical using terephthalic acid as probe molecule. All the
tested samples show photocatalytic ability for the production of this oxidizing
species. Afterwards, the samples were investigated for the removal of methylene
blue. The nanocomposite materials with best adsorption ability for the organic
dye were the ZnS/TNF and Bi2S3ZnS/TNF. The removal of the methylene blue was
systematically studied, and the most promising results were obtained
considering a sequential combination of an adsorption-photocatalytic
degradation process using the Bi2S3ZnS/TNF powder as a highly adsorbent and
photocatalyst material.
